Hello
In this thread you can find a great number of animals with description
Good luck
:rambo:
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Hello
In this thread you can find a great number of animals with description
Good luck
:rambo:
The unusual mammal called the aardvark was named by South Africans in the early 19th century. In the local language, Afrikaans, “aardvark” means “earth pig.” This name aptly describes a large, heavily built animal with thin hair and short, stumpy legs. The aardvark can reach a length of 6 feet (1.8 meters). Its head has huge donkeylike ears, a long snout, and drooping eyelids with long lashes
Aardvarks, which are also called ant bears, live in dry places in Africa south of the Sahara Desert. During the day they sleep in underground burrows. At night they dig underground for their favorite food, termites. Aardvarks use their sensitive snouts to detect these insects. They break open the termites' nests with their massive, flattened claws and suck up the insects with their long tongues. Although they are not aggressive animals, aardvarks can defend themselves by lashing out with their claws. They can also dig very quickly to bury themselves
Female aardvarks give birth to one baby per year. After a few weeks the baby begins to follow its mother around. It feeds and travels with her for about six months until it becomes more independent.
Scientists classify aardvarks in a group called the Tubulidentata, meaning “tube-toothed.” The tubular teeth have no enamel or roots. The scientific name of the aardvark is Orycterops afer
The ocean bird called the albatross is known for its ability to fly long distances with very little effort. There are more than a dozen species, or kinds, of albatrosses. They belong to the family of birds called Diomedeidae.
Where albatrosses live
Albatrosses are birds of the open sea. They have no need to visit land except to nest. Most species, including the wandering albatross and the sooty albatross, nest on remote southern islands and fly over the surrounding oceans. Other albatrosses, however, nest on tropical Pacific islands and fly over the North Pacific Ocean.
Physical features
Albatrosses are among the largest of flying birds. They can weigh as much as 25 pounds (11 kilograms). The wandering albatross has a longer wingspread than any other bird, measuring more than 11 feet (3 meters) across. Albatrosses have big heads, stout bills, and webbed toes that are used for flight control as well as for swimming.
Most adult albatrosses have white bodies. The wings may be a combination of black, brown, and white. Young birds are generally darker and take five years or more to develop adult coloring. A few species, such as the black-footed albatross and the sooty albatross, are brown all over. The most colorful part of an albatross is its large yellow bill.
Behavior
Albatrosses use their long wings to soar and glide on air currents. They can stay in the air for hours without flapping their wings. When they get hungry, they land on the water and fish with their bills. Squid is their favorite food, but they catch fish as well. They also eat scraps cast to sea from passing ships. Like other seabirds, albatrosses drink seawater and get rid of excess salt through a special gland. At sea, albatrosses sleep on the surface of the water.
Albatrosses are majestic in the air but clumsy on dry land. They often land heavily, and they have to run and flap their wings to take off. Sailors sometimes call them gooney birds because of their comical movements. Another common nickname for albatrosses is mollymawk, from the Dutch words for “foolish gull.”
Life cycle
Albatrosses nest in groups on remote islands. Males and females attract each other with dances and displays. Once formed, a male-female pair usually breeds together year after year. The female lays a single large egg in a nest on the ground. Both parents tend the egg, which takes an unusually long time—often more than 70 days—to hatch. The parents care for the chick for three to ten months, until it is ready to fly. The young albatross then goes out to sea until it is ready to mate, about 5 to 10 years later. Because the growth process takes so long, population growth among albatrosses is slow. Albatrosses have few natural enemies, however, and may live more than 30 years.
Albatrosses and humans
With their habit of following ships, albatrosses have captured the human imagination for centuries. Superstitious people once associated the birds with the spirits of drowned sailors. Killing an albatross was thought to be bad luck. Nevertheless, the birds were killed in large numbers, often for their feathers and meat.
Closely related to crocodiles, alligators are large lizard-like animals with long, rounded snouts and powerful tails. They are found in only two countries, the United States and China.
Where alligators live
Only two species of alligator exist on Earth. The larger of the two species is the American alligator. The scientific name of the American alligator is Alligator mississippiensis. It is found in the southeastern United States from North Carolina to Florida and west to the lower Rio Grande. The Chinese alligator (A. sinensis) lives in China in the Yangtze River and its tributaries.
Alligators usually live in slow-moving rivers. They also live along the edges of large bodies of water, such as lakes and swamps. Large adults can stay underwater for over an hour without breathing. Alligators do not have salt glands to remove salt from their body. Because of this, they cannot stay in salty water, such as the ocean, for long.
Although alligators are most comfortable in the water, they are also able to travel on land by sliding on their bellies, stepping with their legs extended, or galloping awkwardly. Alligators dig burrows to escape from danger. They also sleep in these burrows through the winter.
Physical features
The male American alligator grows to an average length of 11 feet (3.4 meters) and can weigh about half a ton. The female American alligator can grow up to 8 feet (2.5 meters). Young American alligators are black with yellow banding on the tail. The adults are brown with dark stripes on the tail.
The Chinese alligator normally grows to a length of 5 feet (1.5 meters). It is blackish with faint yellowish markings.
Alligators have a thick skin composed of close-set, overlapping bony plates called scutes, or osteoderms. They have four short legs. The front legs have five toes, but the back legs have only four. Alligators swim with snakelike movements. Their flat, muscular, oarlike tails provide powerful swimming strokes and are effective weapons as well. Their eyes, ears, and nostrils are located on top of their long head. These can be spotted above the water when alligators are floating at the surface, as they often do.
Although they resemble crocodiles, alligators display some distinctive features. Alligators have a rounded snout, while the snout of most crocodiles is narrow and pointed. When alligators close their jaws none of their teeth can be seen because the fourth tooth in the lower jaw fits into a socket in the upper jaw. The fourth tooth of crocodiles always sticks out at the side of their mouth.
Behavior
Like crocodiles, alligators are basically carnivores, meaning that they eat meat. Young alligators eat worms and insects. As they mature, they add frogs, tadpoles, and fish to their diet. Adult alligators feed mainly on fish, small mammals, and birds, but they may sometimes kill prey as large as deer or cattle. They hunt mainly in water by swallowing their small prey whole. Larger animals are dragged underwater, drowned, and then eaten.
Life cycle
At the time of mating, which is usually in the spring, male alligators give bellowing roars. These roars help establish breeding territories and attract the females. When the time comes to lay eggs, the female builds a mound nest of mud and grass. In this nest, she lays from 20 to 60 hard-shelled, oval, white eggs. They are ready to hatch after about 65 days.
At hatching time the baby alligators start making feeble squeaks. The mother digs the eggs out of the nest. The babies are born with a sharp spike on their noses that they use to break their way through the eggshell. Mother alligators are noted for taking good care of their young. They stay around to protect the eggs and guard the young for as long as a year.
Newborn alligators are about 8 to 10 inches (20 to 25 centimeters) long and face danger from many predators, including fish, birds, and larger alligators. They grow about 1 foot (0.3 meter) in length per year for the first three to four years. After that time, their growth continues more slowly.
Ecological issues
Both the American and Chinese alligator have been killed for their hide, or skin. Their hide is used as leather for handbags, luggage, shoes, belts, and other items. They have also been hunted in order to protect domestic animals and humans. The young of the American alligator have been sold in large numbers as pets. Because of these things, the American alligator has disappeared from many areas where it was once abundant.
The Chinese alligator has become so scarce that it is considered endangered by the International Union for Conservation of Nature and Natural Resources (IUCN).
Allosaurus was a fierce dinosaur that roamed the Earth before the similar but more well-known Tyrannosaurus rex appeared. The name Allosaurus means “other lizard.” This dinosaur had bony ridges above each of its eyes. It also had a ridge of bone running down the center of its face between its eyes to the tip of its snout. Allosaurus is a member of the group of dinosaurs known as theropods. The theropods were meat-eating dinosaurs that walked on their two back legs.
Where and when Allosaurus lived
Allosaurus lived about 163 to 144 million years ago, during the period of the Earth's history known as the Jurassic. Most Allosaurus fossils, or remains, have been found in North America, in Colorado, Utah, New Mexico, Montana, South Dakota, and Wyoming. Remains also have been discovered in Africa and Australia. Allosaurus, like most other dinosaurs, was a land animal. It most likely lived near areas with thick plant life, close to the plant-eating dinosaurs that it preyed upon.
Physical features
Allosaurus was a large dinosaur that stood and walked on its two muscular hind legs. It reached up to 39 feet (12 meters) in length, stood about 15 feet (4.5 meters) tall, and weighed up to 2 tons. The massive head of Allosaurus measured about 3 feet (1 meter) long and was supported by a short, thick neck. Large, open spaces in the skull made its head fairly light. The sharp teeth of Allosaurus were curved and had sawlike edges. They were 2 to 4 inches (5 to 10 centimeters) long. The dinosaur's powerful jaws could open wide to tear off larger chunks of food. Allosaurus had sharp claws on the three toes of each hind foot. It also had long, grasping claws on the three toes of each front foot. These claws grew as long as 6 to 10 inches (15 to 25 centimeters). They helped make the animal's short but strong front legs deadly weapons. The long, heavy tail of Allosaurus may have helped the animal balance itself.
Behavior
Allosaurus was a meat-eating dinosaur that preyed on plant-eating dinosaurs. When it hunted alone, Allosaurus would hide among the thick plants then jump out on its prey. It would grab hold with its long front claws and sink its teeth into the neck of its victim. Some scientists believe that Allosaurus also hunted in packs. Together, a pack of Allosaurus could bring down very large dinosaurs, such as Apatosaurus and Diplodocus. It is possible that Allosaurus was also a scavenger, feeding upon carcasses of dead or dying animals. Scientists believe that Allosaurus reproduced by laying eggs.
The alpaca belongs to the camel family and resembles the llama, to which it is closely related. The alpaca's Latin (or scientific) name is Lama pacos. It is valued for its wool and reared mainly in South America.
Where alpacas live
The alpaca is found on marshy grounds at altitudes above 13,000 feet (4,000 meters). It is presently found in central and southern Peru and western Bolivia in South America. The Indians of the Andes Mountains of South America began raising the alpaca several thousand years ago.
Physical features
Although the alpaca is a member of the camel family, it does not have a hump. Like the llama, the alpaca is a slender-bodied mammal with a long neck and legs, a short tail, a small head, and large, pointed ears. It stands approximately 35 inches (90 centimeters) high at the shoulder, and weighs 121–143 pounds (55–65 kilograms). Its shaggy coat varies in color from black or brown to gray and tan to pale yellow and, occasionally, white. The alpaca has a natural life span of 15–20 years.
Economic importance
The alpaca is bred mainly for its fine wool, and the animal is normally sheared, or trimmed, every two years. Its wool is lightweight, strong, shiny, warm, and stands up to rain and snow. It is sometimes combined with other fibers to make lightweight suit fabrics. There are two breeds of the alpaca, the huacaya and the suri. The suris provide fine fleeces of about 6 12 pounds (3 kilograms) per animal, and the huacayas give coarser fleeces weighing about 5 12 pounds (2.5 kilograms) per animal. Peru is the leading producer of the wool.
Most of the animals known as amphibians can live on land or in the water. The word amphibian comes from a Greek word meaning “living a double life.” Amphibians are vertebrates, or animals with backbones. Amphibians were the first vertebrates to appear on land. The early amphibians were the ancestors of all reptiles, birds, and mammals.
There are three types of amphibians. The first group includes the frogs and toads. The second group consists of the salamanders, including the newts and mud puppies. The third group is made up of wormlike creatures known as caecilians.
Where amphibians live
Amphibians are found all over the world except in very cold or dry regions. They are most common in hot, humid areas such as the tropics. Some adult amphibians live only on land. Other species live only in the water. Most amphibians, however, spend at least part of the time on land and part in the water. They live in the areas between freshwater and dry land or in regions that have plenty of dew and moisture.
Frogs and toads have a very wide range but are most abundant in the tropics. Salamanders mainly live in the regions of the Northern Hemisphere that have warm summers and cold winters. They often live in or near streams and are sometimes found under rocks and logs. Caecilians are found throughout most of the tropics. Most caecilians live underground. Some species live in the water.
Physical characteristics
General features
Most amphibians are relatively small animals. However, they vary greatly in length, from less than 25 inch (1 centimeter) to more than 60 inches (150 centimeters).
Amphibians do not have hair or feathers. The skin absorbs water and oxygen. The skin of most amphibians is moist. In most species, if the skin dries up, the animal soon dies. The animal regularly sheds its upper layer of skin, in a process called molting. The lower layer of the skin often includes mucous glands and poison glands. Mucous helps provide essential moisture to the body. Poison helps the animal defend itself against its natural enemies, such as birds and small mammals. Amphibian poisons rarely harm humans.
The skin's protective properties include the ability to change color. This can help the animal hide from enemies by appearing to be a part of its surroundings. At other times, parts of the amphibian's skin may become brightly colored as a warning for enemies to keep away.
Amphibians usually have flat, wide skulls. Although amphibians have teeth, the frogs, toads, and salamanders do not chew their food. They use their long, flexible tongues to capture their prey, which they then swallow whole.
Frogs and toads
Frogs and toads are tailless. They have large, well-developed eyes. They have short, thick bodies and four legs. Frogs have long, powerful hind legs that are well adapted for leaping and swimming. Tree frogs have suction pads on their fingers and toes so that they can hold on to smooth surfaces. Toads have shorter legs than frogs, and they get around by hopping or walking instead of leaping. The skin of toads has a warty appearance and is usually dry.
The West African goliath frog is the largest of this group. It may grow to nearly 1 foot (30 centimeters) long and weigh as much as a house cat. The smallest is a Brazilian species that is less than 25 inch (1 centimeter) long.
Salamanders
Salamanders have tails. In newts, the tail is flattened. Salamanders generally have short bodies, four legs, and moist skin. They are often boldly patterned or brightly colored. Salamanders have great powers of regeneration. If a salamander loses an eye, a leg, or its tail, it can grow a new one. Most salamanders are about 4 to 6 inches (10 to 15 centimeters) long. However, the Chinese giant salamander grows to 5 feet (1.5 meters) in length. A tiny species in Mexico measures only about 1 inch (2.5 centimeters) long.
Caecilians
Caecilians look like worms or snakes. They are well adapted for tunneling underground. The long, slender body is encircled by numerous grooves. The caecilian generally has a short, pointed tail. The eyes are covered by skin or bone, so the animals are blind or nearly blind. Near each eye is a tentacle, which the caecilian uses to feel its way around. Caecilian species range in length from about 4 inches (10 centimeters) to nearly 5 feet (1.5 meters).
Behavior
Amphibians are cold-blooded, meaning their body temperature is about the same as the temperature around them. When the temperature drops or rises, amphibians change habitats in order to become more comfortable. A drop in the humidity levels can also affect them.
Some species of amphibians are active by day, and others move about at night. If it becomes too hot and dry, some amphibians become inactive until conditions are favorable again. This is called estivation. Some amphibians become inactive during winter if the region is very cold. They seek out mud, trees, and other safe places in which they remain inactive for months, until it is warm enough again. This is called hibernation.
Frogs and toads have a strong sense of location. When taken from their territories, they can find their way back by smell and instinctively by the position of the stars. Many species tend to return to the same breeding grounds year after year.
Adult amphibians consume a wide variety of foods. Frogs, toads, and salamanders feed mainly on small boneless animals such as insects, worms, and spiders. Some large salamanders and frogs eat small birds and mammals. Salamanders eat members of their own species as well. Earthworms form the main diet of caecilians that live underground. Caecilians that live in water eat fish and eels.
Life cycle
The majority of amphibians lay eggs, but some species give birth to live young. In most egg-laying species, the female deposits a large number of eggs in the water. The tiger salamander may lay more than 5,000 eggs, and the large bullfrogs may lay 45,000 eggs. In some species, the eggs develop and hatch on land. These amphibians come out of the egg as miniature adults.
The life cycle of most amphibians is divided into two phases. In the first phase, the amphibian exists in the water in an immature form called the larva. In frogs and toads, the larva is also known as a tadpole. The larva begins life with gills, which allow it to breathe underwater like a fish. The larva stage lasts from several weeks to as long as five years, depending on the species.
In the second phase, the larva develops into the adult form, capable of existing on land at least part of the time. The lungs develop, and the gill slits close. The period of transformation from larva to adult is known as metamorphosis. Metamorphosis brings about an abrupt and thorough change in the amphibian's form.
Conservation
Humans are the most serious threat to amphibians. Amphibians help keep insect populations under control. However, amphibians are often destroyed when people drain marshes to kill mosquitoes and other insect pests. Pollution can also destroy the places where amphibians live. Amphibians are eaten in some countries. Frog legs are considered a delicacy. Also, many amphibians are used in scientific experiments. Many species of amphibians throughout the world have died out or are in danger of dying out.
An anaconda is a giant water-loving snake that is found in tropical South America. It is one of the two largest snakes in the world. There are stories of giant anacondas reaching more than 50 feet (15 meters) in length. Disappearances of people in the jungles of South America are often blamed on the snakes. However, scientists believe such long lengths are exaggerated and that human deaths by anacondas are rare.
Physical features
The largest anacondas reach about 30 feet (9 meters) in length, but most only grow to about 16 feet (5 meters). Only certain pythons grow longer. Anacondas are, however, the most massive snakes, and many people consider them the world's largest because of both their great weight and length. Some weigh 550 pounds (249 kilograms) and have thick, bulky bodies measuring 12 inches (30 centimeters) or more around.
Types of anacondas
There are two types of anacondas, the giant, or green, anaconda and the yellow anaconda. The largest is the giant anaconda. It lives in or near the water of slow-moving rivers and streams in the rain forests of northeastern South America and on the Caribbean island of Trinidad. The giant anaconda is typically brown or olive green in color and spotted with large, black, oval patches. The yellow anaconda lives further south. Its skin is tan or greenish yellow with black, overlapping spots across its back. Both types have eyes and nostrils on the top of the head, which allow the animal to see and breathe while lying hidden in water or mud.
Hunting habits
Anacondas usually hunt at night for mammals, reptiles, and birds. They are known to hunt animals as large as a young deer, but they usually do not try to capture an animal weighing more than 50 pounds (23 kilograms). The snake hunts by surprising its prey. It quickly coils its body around the animal and squeezes until the animal can no longer breathe. Sometimes the anaconda pulls its prey under water and drowns it. It may also crawl on land and even climb into trees to capture birds.
Life cycle
Female anacondas give birth to large litters. A typical litter has 14–82 young that each measure more than 2 feet (0.6 meter) long. Many of these young become prey for other animals. In captivity, anacondas may survive up to about 30 years.
Some people enjoy eating the small fish known as anchovies. Their salty taste can add to the flavor of pizza, salads, and other dishes. Likewise, many larger fish find anchovies tasty. Anchovies make good bait for catching such fish as tuna, sturgeon, and salmon.
Anchovies belong to the scientific family Engraulidae. Most of the more than 100 species, or types, live in saltwater. A few tropical anchovies live in freshwater. Anchovies travel in groups called schools. They come to the water's surface at night to feed on tiny plants and animals known as plankton.
Adult anchovies are about 4 to 10 inches (10 to 25 centimeters) in length. The most noticeable feature of an anchovy is probably its large mouth. The mouth almost always extends behind the eye. An anchovy also has large eyes and a pointed snout.
A female anchovy can lay thousands of eggs each year. The eggs are long and transparent (see-through). They float for about two days before hatching. The newborns, known as larvae, sink to the bottom. The larvae change form to look like adult anchovies after about three months. Anchovies are thought to live as long as seven years.
Stories about legendary animals abounded when much knowledge of the natural world was based on travelers' tales and rumor. An example is The Voyage and Travels of Sir John Mandeville, Knight, written in the mid-14th century, which contained fanciful descriptions of monsters. Even works by scientists contained descriptions of legendary creatures. The Swiss naturalist Conrad Gesner described the unicorn and winged dragons in one book. Some legendary animals, such as the yeti, the Bigfoot, and the Loch Ness monster, still arouse general curiosity.
The most well-known of the legends have appeared in many versions in different works. These include the dragon, various sea serpents, the basilisk, the unicorn, and the phoenix.
Dragon
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The dragon was usually thought of as a huge scaly lizard or snake that breathed fire and had wings like a bat. In Greece the word drakon, from which the English word was derived, was used originally for any large serpent.
In the Middle Eastern world, the serpent or dragon symbolized evil. In Christian art the dragon came to stand for sin. In the Far East, however, the dragon is known as a kind creature. The Chinese dragon represented yang, the principle of heaven, activity, and maleness in Chinese cosmology. From ancient times, it was the emblem of the royal family. Until the 20th century the dragon adorned the Chinese flag.
Sea creatures
Sea serpents were supposed to be enormous snakes, or huge creatures that inhabited the deep sea. Sea serpents have a long history of being sighted by mariners and sailors. Belief in them was widespread throughout the ancient world. Accounts of these fabled creatures might have been based on the sightings of giant squids, which can attain a length of 50 feet (15 meters). Sightings of freshwater “monsters,” especially those in Loch Ness in northern Scotland have been investigated. However, all investigations have been inconclusive. In Norwegian sea folklore, the kraken was an enormous creature, part octopus and part crab. This monster may also be based on chance sightings of the giant squid.
Mermaids were also mythical creatures that lived in the sea. They had the head and upper body of a human being and the tail of a fish. In European folklore, mermaids (sometimes called sirens) and mermen were natural beings who, like fairies, had magical and prophetic powers. Aquatic mammals, such as the dugong and manatee, which suckle their young in human fashion above water, are considered by some to be the basis of these legends.
Basilisk
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The basilisk, or cockatrice, was a serpent so horrible that it killed with a glance. The Roman writer Pliny the Elder described the basilisk simply as a snake with a small golden crown. However, it went on to gain a terrifying reputation. The sight of a basilisk was said to be so dreadful that if the creature saw its own reflection in a mirror, it would die of fright. The only way to kill it, then, was to hold a mirror before it and avoid looking at it directly. In the Middle Ages it was supposed to have the head of a cock, or sometimes a human head.
Unicorn
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The unicorn was a mythological animal resembling a horse or a kid, with a single horn on its forehead. The unicorn appeared in the early artworks of the Mesopotamian civilization. It was also referred to in the ancient myths of India and China.
The earliest description in Greek literature of a single-horned animal was by the historian Ctesias in about 400 BC. The actual animal behind Ctesias' description was probably the Indian rhinoceros. Cups said to be made of unicorn horn, but actually made of rhinoceros horn or narwhal tusk, were highly valued in the Middle Ages as a protection against poisoned drinks.
Phoenix
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Early humans were very interested in birds and attributed magic and religious powers to them. Therefore many mythological creatures, such as thunderbird, phoenix, and roc, have taken the form of birds. In ancient Egypt and in classical antiquity, the phoenix was a fabulous bird associated with the worship of the sun. It was said to be as large as an eagle, with brilliant scarlet and gold feathers. Only one phoenix existed at any one time, and it lived at least 500 years. As its death approached, the phoenix made a nest of boughs and spices, set it on fire, and was consumed in the flames. From the pyre miraculously sprang a new phoenix.
Other creatures
More recent creatures are the Yeti and Bigfoot. The Tibetan yeti was a mythical monster inhabiting the Himalayas at about the level of the snow line. Though reports of actual sightings of such a creature are rare, certain mysterious markings in the snow have traditionally been attributed to it. Bears have probably produced some of these.
A large, hairy creature resembling a human, the Bigfoot is believed by some to exist in northwestern United States and western Canada. It seems to represent the North American counterpart of the yeti. Although some people have claimed to have seen and even photographed the creature, none of the evidence has been verified. Also known as Sasquatch, it is described as ranging from 6 to 15 feet (2 to 4.5 meters) in height, standing erect on two feet, and either moving silently or emitting a high-pitched cry.
The armored dinosaur known as Ankylosaurus had a tail that ended in a large, bony club. It was one of a family of plant-eating dinosaurs that walked on four legs and was protected by heavy armor. Euoplocephalus was another member of this family.
Where and when Ankylosaurus lived
Ankylosaurus lived 70 to 65 million years ago, during the period of the Earth's history known as the Cretaceous. Many Ankylosaurus fossils, or remains, have been found in North America, mostly in Montana, Wyoming, and in Canada. These dinosaurs lived in areas that were thick with plant life and that often surrounded bodies of water, such as lakes.
Physical features
Ankylosaurus was a stocky dinosaur that reached a length of 25 to 33 feet (7 to 10 meters), weighed up to 4 tons, and stood 4 feet (1.2 meters) tall. This dinosaur had small bony plates covering its entire body. In addition to these plates it had rows of small bony projections on its sides and bony knobs on its back. Ankylosaurus also had hornlike ridges in the upper and lower corners of its skull, just behind its eyes. It had a short, wide head and rather weak beaklike jaws with a few small teeth. Ankylosaurus stood and walked on all four of its sturdy legs. The two back legs were longer than the front two, and its feet were wide and hooflike.
Behavior
Ankylosaurus was a plant eater that fed on soft and pulpy low-growing plants and shrubs. This dinosaur, like other plant-eating dinosaurs, swallowed small stones to help grind the plant material in its stomach. Ankylosaurus was a slow-moving dinosaur. It depended on the bony plates covering its body to protect it from its enemies. The club at the end of its tail was used as a weapon in self-defense. When attacked, Ankylosaurus could swing its tail with a great deal of force. Like most other dinosaurs, Ankylosaurus reproduced by laying eggs.
Ants are social insects who live in organized colonies. There are some 8,000 different types of ants in the world. They are found almost everywhere, but they are most common in hot areas.
Physical features
Most ants have the same basic physical structure. They range in size from 8100 to 1 inch (2 to 25 millimeters). They are usually yellow, brown, red, or black. The body of an ant is divided into three sections: the head, the thorax, and the abdomen. The head is large, and the abdomen is slender and oval. The thorax, or midsection, is connected to the abdomen by a small waist. The mouth is an important tool for most ants. It consists of two sets of jaws, the outer pair and the inner pair. The jaws are used for fighting, eating, and carrying food and other materials.
Most ants have simple eyes, called ocelli, on top of the head, as well as a compound eye with many lenses on each side of the head. However, their vision is believed to be poor. More useful than the eyes are the antennae. The antennae are located on the top of the head and help in guiding the ant. They also act as an organ of smell and communication.
Life cycle
The life cycle of the ant has four stages: egg, larva, pupa, and adult. The larvae have no eyes or legs. After the larvae hatch out of the eggs, they shed their skin several times. Most of them spin a silken cocoon around their bodies and rest inside while they grow into adults. When a pupa is ready to break out of its cocoon, a nurse ant bites a hole at the end of the silken wrapping and helps the weak little ant free its legs and antennae. Then she washes and feeds it. Most ants live for 6 to 10 weeks, though some live up to 15 years.
Behavior
There are different classes in the social organization of ants: queens, workers, soldiers, and males. The queen spends her life laying eggs. The workers are females and do the work of the nest; the larger females, the soldiers, defend the colony. At certain times of the year, many species produce winged males and queens. They fly into the air, where they mate. The male dies soon afterward, and the fertilized queen establishes a new nest.
Ants are very social creatures. They live in groups called colonies inside a nest. They make their nests out of many materials, including soil, sand, wood, and leaves. Some ants build anthills. The nest is kept very clean. If an ant dies, a worker carries it from the nest to a place that is a cemetery and a garbage dump. If the queen dies, however, the workers continue to care for her as long as her body is unharmed.
Ants are also capable of warlike behavior. Ants have different methods of defense. Some bite or spit out a disagreeable liquid. Others run away when under attack, “play dead,” or send sound signals to warn other members of their colony of danger.
Among the most curious looking animals in the world are the anteaters. Their long heads and snouts look like tubes, and they have no teeth at all. Their front legs are very strong and armed with heavy, curved claws, which they use to break open the nests of ants and termites. Then, when the insects rush out, they snatch them up with their long, sticky tongues.
Three Species
Anteaters are found in the swamps and forests of Central and South America. There are three species, of which the largest is the giant anteater. The scientific name of the giant anteater is Myrmecophaga tridactyla. Although its body is only about 3 feet (1 meter) long, it measures more than twice that length from the tip of its snout to the end of its long, bushy tail. It weighs about 55 pounds (25 kilograms). Its body is covered with gray hairs, with a band of black across the breast and a white stripe on the shoulders. It spends all its time on the ground, and it may be active both by day and by night. It is not usually a savage animal, but it becomes very fierce if it is cornered. It can do severe damage with the very sharp claws of the forefeet.
The lesser anteater, or tamandua (Tamandua tetradactyla), lives in trees. This species is much smaller than the great anteater, measuring only about half the length. It has a long but not a bushy tail, which helps it to climb on tree branches. Active mainly at night, it feeds chiefly on ants nesting in trees.
The two-toed anteater (Cyclops didactylus) is the smallest of the family. It is the size of a squirrel. Because of the color of its fur it is sometimes called the golden anteater. Like the lesser anteater, the two-toed anteater lives in trees and is most active at night.
The Anteater's Relatives
Various other insect-eating animals are sometimes called anteaters, though they really belong to other groups of animals. One of them is the aardvark, or ant bear. Another is the echidna, or spiny anteater, which is related to the platypus. The pangolin, or scaly anteater, is covered with protective scales. Other relatives of the anteater include the sloth, the armadillo, and the numbat, or banded anteater.
Antelopes are plant-eating animals known for their beauty, grace, and speed in running. The impala, gazelle, addax, gnu, and kudu are all antelopes.
Where antelopes live
Antelopes are found on the large grassy plains of Africa and in the central and southwest regions of Eurasia. Only one antelope, the pronghorn or prongbuck, is found in North America.
Physical features
Most antelopes have horns that sweep up and back. Their coats are generally golden, reddish tan, or gray. The face, belly and rump tend to be white. In size, antelopes generally compare with most goats and deer. The largest and tallest antelope is the African giant eland, about 69 inches (175 centimeters) tall at the shoulders and weighing about 1,764 pounds (800 kilograms). The smallest is the African royal, about 10 inches (25 centimeters) tall at the shoulders and weighing only about 6 pounds (2.7 kilograms).
Antelope horns vary greatly in size and shape. The giant sable antelope has huge horns about 63 inches (160 centimeters) long, while the royal has small spikes that are only 1 inch (2.5 centimeters) long. The four-horned antelope of India has two pairs of horns, one on its forehead and a larger pair on the top of its head.
Antelopes have excellent senses of smell and hearing. This helps them to detect danger and leap to safety. Antelopes can run very fast. The pronghorn can run 43 miles (70 kilometers) per hour and leap 20 feet (6 meters). Thomson's gazelle can run 50 miles (80 kilometers) per hour. The impala, known for its great springing leaps, can jump to a height of almost 8 feet (2.4 meters) and cover 33 feet (10 meters) in a bound.
Behavior
Antelopes are herbivores, which means they eat plants and grass. They follow a circular grazing route over a particular area of land and may cover more than 200 square miles (500 square kilometers) in a year. They generally travel in herds of several hundred antelopes. A few live alone—these are usually old or weak animals, males with no mates, or females about to give birth. A doe, or female antelope, returns to the herd once her young are big enough to follow her.
Life cycle
During the mating season, male antelopes mark territories and then attract the attention of passing does. They do this by rubbing their scent glands against plants and trees. A male will defend his territory from other male antelopes by signaling them to fight. In such a case, two males lock their horns together and wrestle in combat. Neither animal comes to any great harm. One antelope, however, the African eland, has been known to fight to the death. The antelope doe may produce her young after four to eight months.
Survival issues
Some types of antelope have been hunted so much that they no longer exist at all. These include the Arabian oryx, giant sable, blesbok, and bontebok. Other antelopes, such as the eland, roan, greater kudu, and waterbuck, are still being hunted. Some antelopes in danger of extinction are being protected in special parks.
A massive dinosaur, the Apatosaurus weighed as much as five adult elephants. The name Apatosaurus means “deceptive lizard.” This dinosaur may be better known by its former name, Brontosaurus, which means “thunder lizard.” It was called this because of the loud, earth-shaking sound it may have made while walking. Apatosaurus belongs to the group of dinosaurs known as sauropods, which also includes Brachiosaurus and Diplodocus. The sauropods were large, plant-eating dinosaurs with long necks, massive bodies, and four pillarlike legs to support the body.
Where and when Apatosaurus lived
Apatosaurus lived about 147 to 137 million years ago, during the late Jurassic and early Cretaceous periods of the Earth's history. Most Apatosaurus remains have been found in North America, particularly in Wyoming, Utah, Oklahoma, and Colorado. It was once believed that Apatosaurus lived in swampy areas because it needed to live in water to support the weight of its heavy body. Modern scientists now agree that Apatosaurus was mainly a land animal. Studies show that its thick legs, elephantlike feet, and strong skeleton were able to support Apatosaurus on land.
Physical features
Apatosaurus was one of the largest land animals of all time. It reached a length of 70 feet (21 meters), weighed 30 to 36 tons, and stood 15 feet (4.6 meters) tall at the hips. This dinosaur also had a very long neck and tail. Apatosaurus was a quadruped, meaning that it stood and walked on all four legs. It had claws on its large feet. Apatosaurus had a small, horselike head that measured only 2 feet (61 centimeters) in length, and long, peg-shaped teeth.
Behavior
Apatosaurus was a plant-eater. It fed on the leaves and needles of sequoia, fir, and pine trees, as well as ferns and other low-lying plants. Its long neck may have enabled Apatosaurus to reach as high as 35 feet (10.6 meters) to browse the treetops. In order to aid digestion, this dinosaur swallowed small stones to help grind up the plants in its stomach. Fossil sites suggest that Apatosaurus lived and traveled together in herds. Like other dinosaurs, Apatosaurus reproduced by laying eggs. Young Apatosaurus did not join the adult herd until they were large enough and weighed about 1 ton. Apatosaurus reached adulthood at about 20 years of age and lived to be about 100 years old.
The most humanlike of all animals, the ape is often termed anthropoid, meaning, “resembling a human.” Apes and humans are members of the group of animals called primates. This group also includes monkeys, lemurs, lorises, and tarsiers. The apes are divided into two categories: the lesser apes and the great apes. The lesser apes are the gibbons, and the great apes are the orangutans, chimpanzees, and gorillas.
Where apes live
Apes live in tropical rain forests. Both gibbons and orangutans inhabit the forests of southeastern Asia. Gibbons are found in the mainland and islands, and orangutans are found in the lowland rain forests on the islands of Borneo and Sumatra.
Chimpanzees, bonobos, and gorillas inhabit rain forests that lie on or near the equator in Africa. Chimpanzees, in particular, have a wide geographic range and are found in more than a dozen countries of western and central equatorial Africa. Bonobos, on the other hand, are found only in the lowland rain forests of the Democratic Republic of the Congo in central Africa.
Gibbons and orangutans are arboreal, meaning they live mainly in trees. The orangutan, in fact, is the largest tree-dwelling animal in the world. Sometimes adult male orangutans have to descend to the ground to travel long distances, as the smaller tree branches cannot support their weight. Chimpanzees spend time both on the trees and the ground. Chimpanzees and bonobos come down to the ground to cover larger distances. Most of their feeding otherwise takes place on the trees. Gorillas are largely terrestrial, that is, they spend most of their time on the ground.
Most apes are active during the day. At night they lodge in trees and all except gibbons build sleeping nests for the purpose.
Physical characteristics
Apes share many characteristics, yet each species is quite distinctive in appearance. For instance, all apes have hair, but the color and volume varies from species to species. Gibbons range from tan or silvery to brown or black. Orangutans have a long, reddish-brown coat, or pelage, and are sometimes also called the red ape. Chimpanzees sport a coat of brown or black hair. Gorillas have black skin and hair. The adult male gorilla has a prominent crest on top of the skull and a “saddle” of gray or silver hairs on the lower part of the back. Hence mature males are given the name, silverback.
Gorillas, chimpanzees, and orangutans have short, thickset bodies, long arms, and short legs. Bonobos closely resemble chimpanzees, but have longer arms and a more slender body. Gibbons have remarkably long arms though they are the smallest among apes.
Gorillas are the largest apes. They may attain a height of about 5 12 feet (170 centimeters) and a weight of 300–600 pounds (135–275 kilograms) in the wild.
One feature common to all apes, and which separates them from other primates like monkeys, is that they do not have a tail. Like humans, apes have opposable thumbs and toes, which enable them to grasp and hold objects and to climb. Their fingers and toes have flat nails instead of claws.
Behavior
Movies and books have often portrayed gorillas as ferocious. Studies, however, show that they are not aggressive by nature. Gorillas live in stable family groups of 6 to 20 animals that are led by one or two adult males. The adults are protective towards the other members of the group and turn violent only when they are disturbed or when they sense danger.
Most other apes live in groups as well, though the size of their communities varies. Adult orangutans are the only solitary apes. They come together only for a brief period of courtship before mating.
Apes usually eat shoots, fruits, leaves, seeds, and grass. Gorillas live on an entirely vegetarian diet, but other apes may eat insects, birds' eggs, young birds, or rodents. Bonobos may even eat young antelopes, and chimpanzees sometimes stalk and kill young baboons and bush pigs.
Apes are intelligent creatures, particularly orangutans, gorillas, and chimpanzees. Chimpanzees in the wild use sticks as tools. For instance, they cleverly poke twigs, grass, or other objects into ant and termite nests, withdraw them, and eat the insects that cling to these tools.
Trainers and experimenters have taught both chimpanzees and gorillas to solve problems and use sign language. Orangutans in captivity also show considerable skill and are particularly clever with mechanical objects.
Reproduction and growth
Reproduction among apes is similar to humans. Most apes give birth to a single offspring, after a pregnancy of about seven to nine months. Twins are rare. Infants are generally helpless for the first few months after birth and depend entirely on the mother. They become sexually mature when they are 7 years or older, and may live up to 30 years. It has been noticed that apes generally live longer in captivity.
Under threat
The numbers of most ape species in the wild is shrinking because of hunting and destruction of their natural habitat. Many, like chimpanzees and gorillas, have been exported to zoos and research laboratories. In Africa, gorillas and chimpanzees are prized for their meat. In addition, infant apes bring a high price in the illegal pet trade. These species are considered either vulnerable or endangered.
Steps have been taken for their conservation. Several national parks have been established in countries like Rwanda in Africa and Indonesia and Thailand in southeastern Asia for the protection of gorillas, orangutans, and gibbons. In addition, the law in Indonesia and Malaysia protects the orangutan. The gorilla and bonobos are also protected, but illegal hunting of apes continues.
A prehistoric bird, Archaeopteryx is best described as a feathered dinosaur with wings. Archaeopteryx is considered proof that birds developed from dinosaurs, because it had the traits of both. The name Archaeopteryx means “ancient wing.”
Where and when Archaeopteryx lived
Archaeopteryx lived about 159 to 144 million years ago, during the period of the Earth's history known as the Jurassic. All known Archaeopteryx remains have been found in the Bavarian region of southern Germany. Scientists were able to classify Archaeopteryx as a bird because the fine-grained limestone in this region has perfectly preserved impressions of the animal's delicate feathers. Archaeopteryx lived in a tropical environment on islands among coral lagoons. Low, scrubby evergreens were the tallest trees that grew on the islands.
Physical features
Archaeopteryx ranged in size from that of a blue jay to that of a large chicken. It reached 2 feet (60 centimeters) in length and had a wingspan of 2 feet (60 centimeters). It developed long forearms, which were specially adapted to support feathers. Its primary wing feathers match those of modern pigeons, showing that Archaeopteryx could fly or glide. Archaeopteryx also shared several features with a group of small, meat-eating dinosaurs, however. One major similarity was the presence of well-developed teeth. Like these dinosaurs, Archaeopteryx had a long, slender and flexible neck. It had long leg and foot bones, and it had claws on its hands. Archaeopteryx had a long, bony tail, as well. The only difference was that feathers were attached along each side of its tail.
Behavior
Some scientists believe that Archaeopteryx took off by running along the ground and leaping into the air, flapping its wings forcefully. However, other experts believe that Archaeopteryx probably did not have the well-developed breast muscles used by modern birds to take off from level ground. These experts believe that Archaeopteryx most likely spent a lot of time perched in low-growing trees. It may have used its long, sharp claws to haul itself up the trunks of the trees. The animal could then simply launch itself from atop the low branches and glide out on short flights. When it was not in the trees it is possible that Archaeopteryx swam and fished in the lagoons surrounding the islands on which it lived. It may have wandered along the beach, searching for crabs, washed-up fish, worms, and insects. Archaeopteryx, like both dinosaurs and modern birds, reproduced by laying eggs.
Armadillos are small, piglike mammals related to sloths and anteaters. They have a bony armor that protects them from enemies and other dangers. The word armadillo is Spanish for “little armored one.”
Where armadillos live
Armadillos belong to the scientific family Dasypodidae, which contains 20 species. They are found mainly in or near tropical regions of Central and South America. One species can be found in the central United States. Most species inhabit open areas, but some live in forests.
Physical characteristics
Armadillos are stout, short-legged animals with strong, curved claws. They are usually brownish black, marked with yellow above and yellowish white underneath. Their armor is made up of solid plates and flexible bands. It covers most of the body, including the head and usually the tail. The three-, six-, and nine-banded armadillos are named for the number of movable bands in their armor. Species range in length from about 6 inches (15 centimeters) to 5 feet (1.5 meters).
The coat of armadillos varies among the species. Some armadillos, such as the nine-banded species, have very little hair. The pink fairy armadillo, however, has a fairly dense coat of soft, white hair on its underparts and sides.
Behavior
Armadillos live alone, in pairs, or in small groups. They are usually active at night. They live in burrows and can dig very quickly. Armadillos feed mainly on termites and other insects, worms, roots, and small animals. They can run surprisingly fast on their short legs and are good swimmers. Before entering the water they swallow air to help keep afloat.
Armadillos are timid animals. When threatened, they retreat to their burrows when possible. If caught in the open, they draw in their feet so their armor touches the ground. They may also run away or claw at the attacker. The three-banded armadillos are able to roll up into a ball to protect their underparts.
Female armadillos of some species bear one to 12 identical young. All develop from a single egg, or ovum, and are the same ***.
Baboons are large monkeys that move around both on the ground and in trees. They are very smart, noisy, and often ferocious.
Where baboons live
Baboons are found in Africa south of the Sahara and in Arabia. They are able to live in a variety of places, including open woodlands, grasslands, and rocky hills. They spend most of their time on the ground, but they sleep in high places, including in trees and on cliffs.
Physical features
The head and face of a baboon are similar to those of a dog. Baboons have large cheek pouches and a long muzzle, or snout. Their front teeth are huge, and their limbs are powerful. They walk on all four legs.
Depending on the species, or type, a baboon can weigh from 30 to 88 pounds (14 to 40 kilograms) and measure from 20 to 45 inches (51 to 114 centimeters) long, not including the tail. A baboon's tail is usually about 16 to 28 inches (41 to 71 centimeters) long. Adult males are about twice the size of adult females.
Baboons can be different colors, including ash gray, reddish brown, olive brown, and yellow green. No matter what the color is, however, a baboon's fur is always rough. Adult males often have capes of long hair over their shoulders. The underparts, hands, feet, face, and buttocks of a baboon do not have fur.
Behavior
Baboons eat many different plants and animals, including grass, fruit, roots, birds, and small mammals such as rodents, hares, and gazelle fawns. Their diet varies from region to region depending on what food is available. Baboons can be very destructive to farmland.
Baboons live and travel in large groups called troops. Each troop is a very close society. Troops are led and guarded by one or more males. Baboons communicate with each other and have a number of calls that mean different things. For example, they announce alarm with a doglike bark. Baboons are thought to be very smart creatures that can be trained.
Life cycle
Male and female baboons do not stay together after mating. Instead they mate with other members of the opposite ***. Female baboons typically give birth to a single young. Although females remain with their mothers as they grow older, males leave at about age 7 to join other troops. Baboons may live 20 to 30 years in the wild and considerably longer in zoos.
Badgers are mammals known for their powerful digging. The eight species, or types, of badgers differ in color and size, but all belong to the weasel family. Another member of the weasel family, the ratel of Africa and Asia, is called a honey badger, but scientists do not consider it to be a true badger.
Where badgers live
Badgers live in grasslands and forests. They are found on all northern continents and on many islands. The American badger lives in the western part of North America, from Canada to Mexico. Its territory centers on the Great Plains. The Eurasian badger can be found across the entire length of Europe and Asia, from Great Britain to Japan. Other badgers, including the hog badger, three kinds of ferret badgers, and two kinds of stink badgers, live in Southeast Asia and the large islands nearby.
Physical features
Badgers are mostly medium-sized animals, heavily built with short legs. The American badger sometimes appears to be wider than it is tall. It is about 9 inches (23 centimeters) high and 17 to 30 inches (43 to 76 centimeters) in length, with a weight of 8 to 25 pounds (4 to 11 kilograms). Most of its coat is gray, but it has a blackish face and feet and a white stripe from its nose to its back. The Eurasian badger is the largest of the badgers. It weighs between 22 and 50 pounds (10 and 23 kilograms). It is grayish with large black-and-white stripes on its face. Other badgers also have fur patterns of black and white.
Behavior
Badgers have strong forefeet, and their claws are built for digging. The American badger is a faster digger than a human with a shovel. Badgers dig to get at the burrowing rodents and other underground creatures that they eat. Badgers sometimes eat birds and plants as well. They feed mainly at night.
Badgers also use their digging skills to make burrows for themselves. American badgers live alone in their burrows, but Eurasian badgers live in groups with extensive networks of homes and escape routes. Badgers do not hibernate through cold winters, but they do stay underground for long periods.
Badgers are strong for their size and can fight savagely when threatened. All badgers have scent glands near the tail, but the stink badgers are especially known for shooting a foul-smelling liquid at their enemies.
Reproduction
For most badgers, the time between mating and the birth of the young is quite long. In American badgers the period of pregnancy may be seven months or more, and in Eurasian badgers it may be almost an entire year. Litters consist of one to seven young. The young are raised in the burrow until they are several months old.
Badgers and humans
Badgers help humans by eating many rodent pests, which may carry disease or damage crops. But some people consider badgers to be pests, too, because their burrows can be a hazard to cattle and horses. Such large animals have been known to break legs by stepping into a badger hole.
In the past, badgers were a valuable source of fur. Badger fur has been used as a trim on many types of Native American clothing.
Bold and curious, barracudas are among the most ferocious fish in tropical waters. The species known as the great barracuda has even been known to attack humans. Barracudas live in the warmer parts of the Atlantic and Pacific oceans, including in the Caribbean Sea.
Physical features
A barracuda has a fierce appearance. Its long mouth has a jutting lower jaw and large, knifelike teeth. Its torpedo-shaped body, built for speed, has small scales and two well-separated fins on the back. Barracudas vary in size, but they average 3 to 4 feet (1 meter) in length. The largest type is the great barracuda, which can reach a length of 8 feet (2 meters).
Behavior
Barracudas are primarily fish eaters. They prey on smaller fish like mullets, anchovies, and grunts. Sometimes they even bite through fishermen's nets to get at the fish inside. Barracudas travel far in search of food. When they find a school of fish, they circle around it until the fish huddle together in fear. Then the barracudas dive into the group while biting and slashing with their teeth. Barracudas will strike at most moving objects, including swimmers.
The only mammal that flies is the bat. Because of this trait, bats are often mistaken for birds. Bat wings differ from bird wings, however, in that they are covered with skin, not feathers.
Where bats live
About 900 kinds of bats are known, more than any other kind of mammal except rodents. They are found worldwide but are particularly abundant in the tropics. The United States is known to have 40 species of bats. In North America the little brown bat is the most common type.
Bats generally prefer dark places such as caves, hollow trees, or attics. Some bats, however, rest outdoors on trees or rocks. Usually bats are found in groups, or colonies, ranging from a few dozen to hundreds of thousands of individuals.
Physical characteristics
Bats vary greatly in size. The largest of the bats known as flying foxes has a wingspread as wide as 5 feet (1.5 meters). The wingspread of the tiny Kitti's hognose bat, however, is only about 6 inches (15 centimeters).
Bats also display variety in color, fur texture, and facial appearance. The muzzle often resembles that of a rodent or fox. The ears point forward and are usually very large. Bats have fur in shades of gray, tan, brown, or black on the back and in lighter shades on the sides.
Bats have long arms and hands, with especially long fingers. The fingers are joined by a thin membrane that extends from the arms to the tiny legs. This membrane serves as the bat's wings.
Feeding habits
Nearly all bats rest during the day and search for food at night. Most bats eat insects. A brown bat may eat half its weight in insects in one night. In some parts of the southern United States, huge roosts, or shelters, have been erected for bats because the bats are so useful in controlling the insect population.
Some bats have specialized diets. Several species are carnivorous, or meat eating. They feed on a variety of prey, including birds, smaller bats, rodents, and fish. Other bats feed on fruit, pollen, and nectar. The famous vampire bats of South and Central America feed on the blood of mammals and large birds. These bats sometimes serve as carriers of rabies.
Life cycle
Female bats usually bear one young at a time. The pregnancy can last from six or seven weeks to five or six months, depending on the species. Infants are born nude or with light fur. They nurse for five or six weeks or for as long as five months.
Bats have a long life span for animals of their size. Some bats are known to have lived more than 20 years.
Flight and navigation
Bats are well adapted for flying. Most bats cannot walk or run. A bat's legs and feet are only strong enough to hold on when it hangs upside down from a perch, which is how bats rest or sleep. To start flying, a bat drops from its perch. If it is on the ground it usually crawls to some height, using its wing hooks and weak legs, until it can drop into the air. It can, however, take off from a position on the ground if necessary.
Bats can chase insects through thick forests on the darkest night without striking a branch or twig. While flying, most bats send out a continuous cry, so high-pitched that people cannot hear it. These sounds are reflected by obstacles in the bat's path and echo back to the bat's sensitive ears. The animal instantly responds to the signals and avoids the obstacles.
Bears loom large in legends and folk tales. Stuffed bears and fictional bears such as A.A. Milne's Winnie the Pooh continue to delight children. However, bears also call to mind images of fierce creatures. Despite their reputation for ferocity, most bears are mild tempered animals. They become violent only when their food supplies or their young are threatened.
Where bears live
Bears are found in North America, Europe, and Asia. One species lives in South America. However, there are no bears in tropical Africa, a region otherwise well stocked with large mammals.
The polar bear lives mostly in the Arctic north, where its white fur blends in with snow and ice. Polar bears are often seen on drifting masses of floating sea ice called floes. Brown bears, once widespread in Europe and Asia, are now rare. The grizzly bear, a brown bear of northern and western North America, has been killed off in many areas. The Kodiak bear, an Alaskan island bear closely related to the grizzly, is the world's largest living flesh-eating land mammal.
The American black bear is smaller than the brown bears. It still ranges widely in the forests of the United States and Canada. There is also an Asian, or Himalayan black bear. Most bears live in cold or temperate climates, but the sloth bear is a creature of the tropics. It lives in India and Sri Lanka. The sun bear, or Malayan sun bear, lives in the forests of Southeast Asia. The spectacled bear, which gets its name from the light-colored rings around its eyes, is the only bear of the Southern Hemisphere. It is found in the Andes Mountains of Chile, Bolivia, Ecuador, and Peru.
Physical characteristics
Bears vary in size according to their species. Generally, their height ranges from 3 to 10 feet (1 to 3 meters). The sun bear is the smallest, at 60 to 143 pounds (27 to 65 kilograms). The Alaskan brown bear known as the Kodiak bear is the largest. It weighs up to 1,720 pounds (780 kilograms). Most bears climb trees with ease and swim well. The polar bear has furry soles to its feet that help it run safely over smooth ice. It also has a membrane between its toes for swimming. Bears have poor eyesight, and most have only moderate hearing. Their sense of smell, however, is extremely keen.
Food habits
Biologists classify bears as carnivores, or meat eaters. The polar bear lives on a diet of walrus, seals, and fish. Other bears eat large quantities of vegetable matter, especially roots, seeds, nuts, and berries, as well as meat. Because they eat both meat and vegetables, bears are sometimes referred to as omnivores, or eaters of everything. Bears will even feed on the carcasses of dead animals where they find them. They also sometimes rummage through garbage dumps, making nuisances of themselves.
Behavior
Bears are solitary creatures that avoid each other except in the mating season. Female bears give birth to one to four cubs at a time, usually in winter. Newborn cubs are small, hairless, and helpless creatures unable to open their eyes for about a week. A newborn grizzly bear weighs as little as 1 pound (0.45 kilogram). Cubs drink their mother's milk for about two months and stay with her until the next breeding period begins, which is usually about a year and a half after their birth. Bears begin to breed at 2 to 6 years of age. The male bear plays no role in raising the cubs. Most bears live from 15 to 30 years in the wild. Captive bears have lived much longer.
During the winter most bears in the wild become inactive for a period of two to six months. In the autumn season the bears eat a great deal and seek out comfortable dens where they can sleep for a long time. This process is similar to hibernation, in which animals sleep through the winter. However, bears are not true hibernators. Their heartbeat rate, body temperature, breathing rate, and blood pressure do not drop significantly lower than normal. And on mild days in midwinter, a bear may come out of its den.
Survival
Tens of thousands of years ago Europeans of the Stone Age hunted the cave bear, a very large species that is now extinct. Bears are still hunted as trophies, or for various assets such as their meat, fur, teeth, and fat. Because of extensive hunting and destruction of their habitat by humans, the brown bear has been almost eliminated from many parts of Europe. In North America the grizzly bear had a reputation for ferocity and was a favorite prey of hunters. During the 19th century grizzlies almost died out in the United States.
Bears are now protected in national parks of many countries, and hunting is carefully regulated. In 1973 conservationists agreed that urgent measures were needed to save the polar bear. As a result, all countries bordering the Arctic Circle now protect the animal. Polar bears cannot be hunted, except by local people using traditional weapons. In the mid-1980s conservationists established programs to protect the grizzly bear population in the western United States.
The large rodents called beavers are known for using their teeth and paws to build lodges, storehouses, dams, and canals. Beavers are amphibious, which means they are able to live both in water and on land.
Where beavers live
Beavers are native to North America, Europe, and Asia. Today they are found mostly in the northern wooded regions of North America and Europe. Beavers live most of their lives in or near water. They settle along banks of streams, rivers, and lakes bordered by woodland.
Physical features
Beavers are the largest rodents in North America and the second largest in the world after the capybara of South America. An adult beaver may grow to be about 4 feet (1.3 meters) long, including its tail. It may weigh more than 60 pounds (27 kilograms).
A beaver's thick body is covered with a coat of long, reddish-brown outer hairs and soft, dense, brown underfur. This warm, waterproof coat allows the beaver to swim in icy water in the wintertime. Most of a beaver's features—the fur, toes, tail, ears, nose, and lips—allow the animal to live in the water as well as on land. For example, beavers have ears and a nose that are equipped with valves that close when the animal swims underwater. In addition, a beaver's lips close behind its big front teeth so the animal can cut wood and branches underwater. Because of these features, a beaver may remain underwater for up to 15 minutes.
A beaver's front feet are small and look much like a human hand. Beavers use their hands to pick up and carry objects. The tail is scaly, flat, and shaped like a paddle. A beaver uses its tail to warn other beavers of danger by slapping it on the water's surface and making a loud noise.
Behavior
Beavers are nocturnal, which means that they do most of their building and food gathering at night. Beavers eat fresh green bark and the buds, leaves, and twigs of certain trees. In the summer they also eat water plants, berries, swampwood, and fruit.
Beavers are social animals that live and work together. Large groups of beavers build dams in narrow, shallow parts of streams. The beavers begin by gnawing down a number of young trees. They drag these trees to the dam site and bury them in mud. Into this foundation the beavers fit and pile more young trees, adding mud and stones until a strong barrier is completed. Sometimes the beavers build canals to help move logs that are too heavy to drag overland.
The artificial pond created by the dam is where the beavers make their storehouses and permanent homes, or lodges. A lodge is usually the work of a pair of beavers. It is made up of a platform of carefully interlaced branches held together by clay and dead leaves. A dome-shaped roof covers the platform. The lodge may be more than 5 feet (1.5 meters) high. Entrances to the lodge often open underwater. This allows the animals to pass in and out below the winter ice. Another entrance is used for bringing in wood for food. A lodge may be home to as many as eight animals, including an adult pair and two sets of offspring.
Life cycle
Beavers usually mate with the same partner for life. The female is pregnant for about 105 days before giving birth to her young, which are called kits. A litter includes one to nine kits, with four being the most common size. Kits learn to swim when they are only a month old. Beavers may live as long as 19 years.
Beavers and humans
Beavers have been hunted for their fur, their tails, and their musk glands. Musk glands are scent glands at the rear of a beaver's body that produce a liquid used to make perfumes. During the 17th, 18th, and early 19th centuries, beaver skins were an important part of the world's fur trade. In fact, much of the exploration of North America was prompted by the search for beaver fur. Beginning in the 20th century, however, conservation laws were passed to protect beavers throughout the world. As a result, beavers have been saved and resettled in areas where they had once been common.
For at least 4,000 years honeybees have been kept for their honey and for beeswax, a substance used to make candles, ointments, and many other products. Honeybees and bumblebees are the best-known types of bees, but there are more than 20,000 bee species in all. They live all over the world except in Antarctica. Bees are related to wasps, hornets, and ants.
Structure and form
Most bees have short, thick bodies covered with hair. Like all insects, they have six legs and three body parts: head, thorax, and abdomen. The thorax has three segments. Each segment has a pair of legs; each of the last two segments has a pair of wings attached to it.
When in flight, a bee makes a humming sound because of the rapid movement of its wings. Normally, most bees fly at about 12 12 miles (20 kilometers) per hour, but they can go much faster.
Bees can see color, pattern, and movement with the help of three eyes on top of their heads and two huge, helmetlike compound eyes. Bees see all colors that humans do except red; in addition, bees see ultraviolet, which humans cannot. On the lower part of their heads, bees have biting jaws (mandibles) and a mouth-tongue (proboscis), which they use for sucking and lapping nectar from flowers. The female bee has a device called an ovipositor located at the end of its abdomen. The female bee uses the ovipostor to lay its eggs. It also uses the ovipositor as a weapon to inflict a painful sting. Most bees can sting many times, but a honeybee worker has a tiny, hook-shaped barb that is caught inside the victim. This bee cannot fly away without tearing out its ovipositor and dying. Male bees cannot sting.
Size
The largest bees, which include some of the leafcutter and carpenter varieties, may be up to about 1 12 inches (4 centimeters) long. Bumblebees are larger than most bees—about 1 inch (2.5 centimeters) long. Honeybees range from about 12 to 1 inch (1.3 to 2.5 centimeters), depending on the species. Some of the small leafcutter bees are only 13 inch (1 centimeter) long, and sweat bees are 310 inch (0.7 centimeter) long. The tiniest species, the mosquito bees, may be only 7100 inch (0.2 centimeter) long.
Color
Most bees have black bodies, many with yellow or brown markings. Others have yellow, red, brown, and metallic green or blue bodies, some with brilliant metallic red or purple markings. Honeybees are dark brown with dark yellow stripes. Bumblebees are usually black with wide yellow or orange bands.
Behavior
Nesting
Different species of bees nest in different ways. There are three types of bees based on the way they nest: social bees, solitary bees, and parasitic bees.
Social bees are members of colonies in which they cooperate with others to build the nest and feed and protect the young. They include honeybees, bumblebees, and tropical stingless bees. Social bees are divided into three castes, or classes. Males are called drones. There are two types of females: queens and workers. Both queens and workers lay eggs, but only the queens' are fertilized with the drones' sperm and develop into females. Eggs of the workers develop into males. Queens are not hatched as queens; they become queens when they are fed royal jelly, a substance produced by the salivary glands of the workers.
Most bees are solitary bees. They care only for themselves and their immediate family. Each female makes its own nest and cares for its offspring.
Parasitic bees, or guest bees, do not feed or care for their offspring. They sneak into the nests of other bee species to lay their eggs. They then let the workers of the other nests care for their offspring.
Feeding and pollination
Bees get all of their food from flowers. The food consists of nectar and pollen. Nectar is a sweet liquid produced by the flower's glands. The bees use their long proboscises to drink the nectar. Some bees, especially the honeybee, modify and store their nectar as honey.
Flowers also produce pollen in the form of tiny grains that cling to the bees' bodies. As bees go from one blossom to another, some of the pollen is transferred to the flowers of other plants of the same species. In this way, bees help pollinate, or fertilize, the flowers. This permits the plants to produce their fruits and seeds. The bees' greatest value by far is as pollinators of plants.
The term beetle refers to thousands of different insects. There are so many beetles that they make up almost 20 percent of all known species of animals in the world.
Where beetles live
Beetles are found all over the world except in Antarctica. Most of the species live on the land. However, some, like the whirligig, water scavenger, and true water beetle, have adapted to live in the water.
Physical features
Like other insects, beetles have three major body segments: the head, thorax, and abdomen. A beetle's head has one pair of antennae and a pair of compound eyes. The thorax has two pairs of wings and three pairs of legs. The abdomen of a beetle has the reproductive organs.
Beetles have antennae, or feelers, to help them find food and recognize other beetles. The body is covered with a hard layer called cuticle that supports the internal organs and protects the body. Beetles have chewing jaws called mandibles.
Beetles are colorful insects ranging from brilliant orange, red, or yellow to iridescent green or blue with a metallic sheen. Some are plain black or have brownish patterns that camouflage them on wood or soil.
Beetles vary in size. Some are only about 1100 inch (0.025 centimeter) long, whereas tropical rhinoceros beetles and goliath beetles may reach lengths of 4 to 6 inches (10 to 15 centimeters). At one time, all beetles were flying insects, but many, like the common ground beetle, have given up flying and move about on their six legs.
Behavior
There are two kinds of beetles, the helpful and the harmful. The helpful kind are valuable because they prey on insect pests and useless garbage that collects in houses, hedges, tree stumps, birds' nests, and similar places. The harmful kinds are those, both adults and larvae, who destroy crops and timber and spread diseases.
Beetles stridulate, or make a high-pitched sound, by rubbing one part of the body against another. This is done by scraping the legs over very fine ridges on another part of the body. When frightened, some of them eject an unpleasant-smelling liquid from the end of their body.
Life cycle
Many beetles produce light and sound to either attract a mate or frighten an enemy. A male beetle, such as a firefly, flashes its light to say that it is ready to mate, and a female returns the signal.
The females lay fertilized eggs. When active larvae called grubs hatch from the eggs, they spend all their time eating. Most grubs eat leaves, flowers, stems, roots, and even the wood of trees. They shed their skin as they grow until they become pupae, when they are soft, pale and inactive. After this stage they emerge as fully grown beetles. The life span of a beetle ranges from a few months in some species to more than four years in others.
From pigeons in big cities to penguins in the remote icy land of Antarctica, all birds have similar characteristics. They all have wings, though they cannot all fly. All birds also have feathers. In fact, that is the one characteristic that makes them unique since birds are the only animals that do have feathers.
Where birds live
Birds are found almost everywhere on Earth, from the Antarctic ice caps to tropical forests. There are more than 9,000 known species of birds.
Many birds migrate long distances between winter and summer homes in search of a constant food supply. For example, after nesting and raising their young, many European birds travel to Africa for the winter.
Physical features
Flight
Birds are able to fly because of their body structure and feathers. A flying bird's body is slender and tapers like a jet airplane. However, not all birds can fly. Penguins spend their time in the water and ostriches have undeveloped wings. Because of this, they must walk or run everywhere. Most birds alternate some walking and swimming with their flying.
Feathers
A bird's feathers protect it from rain, cold, and heat. Water slides off a bird's feathers without soaking through. Birds fluff out their feathers on cold days. These fluffed feathers hold a layer of warm air next to their skin. In hot weather birds flatten their feathers close to their body. This keeps their skin cool by preventing hot air from reaching it. The entire covering of feathers on a bird is called plumage. A bird's feathers wear out and are replaced in a process called molting. All birds molt at least once a year, usually in the summer or early fall. Birds also preen their feathers. Birds preen by using their bill to clean, rearrange, and apply oils to their feathers.
Coloring
In many species of birds the male is more brightly colored than the female. The dull color of the females helps them to remain hidden in their nest. In some cases, the brightly colored male perches a short distance away from the nest. In this way, the male bird draws the attention of enemies to himself and away from the eggs and young.
Metabolism
Like humans, birds are warm-blooded. This means that they have a constant body temperature that is not affected by the temperature of their surroundings. Their hearts beat faster than human hearts, however, and birds breathe more rapidly than humans. Because of this, birds have a high metabolism, meaning that they use up energy very quickly. Therefore, some small birds must eat almost constantly while they are awake.
Senses
Birds have very sharp eyesight. An American kestrel hovering 100 feet (30 meters) above a field can spot a grasshopper and drop directly on it. A thin transparent membrane extends across a bird's eyeball. This membrane keeps the eye moist and protects it from dust. A bird's ears are round openings on either side of the head. In general, birds have a narrower range of hearing than human beings. In most birds the sense of smell is not important for survival.
Size
Birds vary greatly in size. The bee hummingbird of Cuba is generally accepted as the smallest living bird. It is 2 12 inches (6.3 centimeters) long and weighs about 110 ounce (less than 3 grams). The largest living bird is the ostrich. Ostriches can stand 8 feet (2.5 meters) tall and weigh 300 pounds (136 kilograms).
Other features
A bird's bones are hollow and very light. Birds also have a beak and a feature called a crop, which is a pouchlike enlargement of the throat. The crop is used to store food. The gizzard is a part of the stomach where digestive juices break down food. The neck of a bird moves more freely than that of any other animal. A flexible neck allows the bird to look out in all directions for approaching danger. The flexible neck also helps the bird catch food and preen its feathers.
Behavior
Birds communicate with one another by using many different sounds. For example, some baby chicks stop moving when their mother produces a danger call. A male bird will perch somewhere, such as on a telephone wire or tree branch, and sing loudly to inform other males that a certain territory belongs to him. The same song is also used in courtship to attract the female.
Birds keep their feathers clean and smooth. All birds like to bathe. Some even take dry baths in dust, sand, and snow. Such bathing may help get rid of pests in the feathers.
Some birds, such as falcons, live alone. Other birds are more social, such as the guanay cormorants of South America that nest in large groups.
Feeding habits
Many birds are insect-eaters. They have developed special abilities to catch insects. For example, some birds catch insects by probing for them with their long, sticky tongues. Others dig in the ground with their bills. Birds of prey have claws and hooked bills for feeding on larger animals. Herons have spearlike bills for catching fish. Some birds feed on plant material, such as seeds, fruit, or nectar. Many birds eat a wide variety of foods.
Reproduction
Each year, many species of birds return to their summer homes, choose their mates, build their nests, lay eggs, and rear their young. The number of eggs in a set varies from 1 to about 20. Nests may be a scrape in the sand or an elaborately woven hanging structure. A type of bird called the swift uses its saliva to hold together branches when making its nest.
Most birds sit on their eggs to hatch them. This process, called incubation, takes from 11 to 80 days. The length of time that parents care for young birds varies widely. Some young are capable of finding food for themselves almost immediately. Others depend entirely on their parents for food.
Birds and human beings
Humans have interacted with birds in various ways throughout history. In the mythology and literature of many cultures, birds are often featured as characters. Many people enjoy keeping birds as pets, and zoos in many cities import birds from different lands for people to see in person and learn about. Humans have also used birds for their own purposes. For instance, pigeons have long been bred and trained for carrying messages. Birds such as chickens and turkeys are often raised for their meat, and the eggs of certain birds are a source of food for many people.
Birds have also been valued for their feathers, which have been used for decoration since early times. Their use in the headdresses of Native Americans is well known. Ostrich farms have been created to produce the soft and fluffy ostrich feathers that are used to make fans. Large quills were once widely used for writing, and feathers have often been used on arrows.
Humans can have a negative impact on the bird population because of this interest. In the past many birds were killed for their feathers and quills. In addition, bird habitats are destroyed throughout the world when people cut down trees to create farmland, houses, and other buildings. Pollution also destroys bird habitats. When a habitat is destroyed, the birds are forced to look for a new place to live. Many birds do not survive this move, and in some cases, entire species die out.
Birds that pursue other animals for food are called birds of prey. They are also called raptors. Birds of prey are usually fairly large in size. They have good eyesight that helps them see their prey from far away. Their hooked beaks and sharp claws are useful for holding, carrying, and killing prey. Birds of prey can be found all over the world. Some common birds of prey are buzzards, eagles, falcons, hawks, ospreys, owls, and vultures.
Behavior
Most birds of prey hunt by sight during the day. They then sleep at night. Owls, however, hunt at night and sleep during the day.
Birds of prey eat many different kinds of animals. Some eat reptiles such as snakes and frogs. Others eat birds, insects, or rodents. A few birds of prey feast on carrion, which is the flesh of dead animals. Birds that only eat fish, such as penguins, pelicans, and storks, are generally not considered to be birds of prey.
Reproduction
Many birds of prey mate for life. They build nests in trees, on ledges of cliffs, or on the ground. Many lay only one egg at a time, and few lay more than four. Owls are an exception to this rule as they can lay up to 12 eggs at a time. The eggs are usually rounded ovals, white or greenish, and spotted. Occasionally they are completely covered with brown or red-brown pigment. The eggs hatch in the order in which they were laid.
Just after the birds have hatched, they usually receive a lot of attention from their parents. Later, parental attention is steadily reduced until the young are left alone except for brief feeding visits. The young birds make their first flights on their own, without the prodding of their parents.
Relationship to humans
Birds of prey are helpful to humans because they eat dead animals and control rodent populations. However, many of them are facing extinction. In some cases birds of prey are destroyed by humans because the birds are believed to kill small domestic animals. Birds of prey have also been harmed by the effects of human activity on their food sources and habitats. As the human population has grown, more and more trees have been cut down to provide land for farming. This has limited the number of areas where these birds can live. Birds of prey need a large amount of space for their territories so they do not have to compete with other birds for food.
Chemicals used to kill pests have also harmed birds of prey. This happens when the birds of prey eat animals that have earlier eaten plants containing these poisonous chemicals. The poisons in the animals cause the birds of prey to lay eggs with thin shells. These eggs can break before the young hatch. Therefore the birds of prey may have fewer chicks. This problem is made worse because birds of prey lay only a few eggs at one time.
The so-called American buffalo that used to roam by the millions on the North American plains is actually a bison. The American, or plains, bison is the largest land mammal in North America. The only other species, or type, of bison is the European bison, or wisent. The true buffalo are a different group of animals found in the warm regions of Africa and Asia. Both bison and buffalo belong to the scientific family Bovidae.
Where bison live
At one time, large herds of American bison roamed the area from Mexico to northern Canada and from the eastern United States to west of the Rocky Mountains. Most lived on open prairies. Today, however, the American bison is found mainly in protected areas such as national parks. The European bison used to range over Eastern Europe, but it is now found in restricted areas mostly in Poland and Russia. It lives in woodlands.
Physical features
Bison are large, powerful animals. A fully grown bull, or male bison, stands about 612 feet (2 meters) tall at the shoulder and weighs about 2,000 pounds (900 kilograms). An adult female is about 5 feet (1.5 meters) tall and weighs about 700 pounds (320 kilograms). The European bison is slightly larger than the American bison but is not as heavily built. A bison has a huge head and a hump at the shoulders. Two short horns curve upward. A female's horns are more slender than a male's.
A bison's fur is coarse, shaggy, and dark brown. It grows especially long on the head, neck, and shoulders and usually forms a beard on the chin. The hair on the bison's front is permanent, but the hair on its hind parts is shed each year, beginning in March. By early summer those parts are quite bare. For protection against insect bites, a bison wallows in mud or shallow ponds to cover its body with mud or clay. When the mud or clay dries in the sun, it forms a protective cover. By October new hair has grown on the hind parts. The fur is at its fullest in November and December.
Behavior
Bison prefer to eat grass and herbs, but they also eat twigs and leaves. They move around in small groups, or bands. A band of bison is usually made up of one or more females and several generations of their offspring. Adult males live somewhere outside a band's territory or form their own small groups. The cow, or female bison, usually gives birth to a single calf in May after about nine months of pregnancy. All members of the band protect the young.
Sometimes large herds form when dozens or even hundreds of bands come together. Herds of bison may make short seasonal migrations. They travel a few hundred miles southward in winter and then move back north when warmer weather returns.
Bison usually move with a plodding walk, but they also trot and run. Despite their size, they are agile and fast. They can run at speeds of 40 miles per hour (65 kilometers per hour).
Bison and humans
For the Plains Indians the American bison was the most important game animal. The Indians ate fresh bison meat or preserved the meat by drying and pounding it. Bison hides provided material for tepees and robes.
About 30 to 60 million bison roamed over North America when Europeans arrived in the 16th century. As white settlers moved westward in the 18th and 19th centuries, however, the number of bison dropped dramatically. The settlers killed millions of the animals for food, for hides, or just for sport. By the 1880s fewer than 1,000 American bison were left, most of them in Canada.
At the start of the 20th century, as the American bison neared extinction, cattlemen and conservationists came together to protect the remaining animals on government land. In the early 21st century there were as many as 200,000 American bison, and they were no longer in danger of extinction.
The European bison also came close to extinction. For centuries the animals have been protected on government lands in Poland. Today European bison are kept and bred in other countries as well. Some animals have been released into the wild. Their numbers remain low, however.
There are many types of blackbirds—small birds whose name comes from the black color of the males' feathers. The best-known type is the red-winged blackbird. Other kinds of blackbirds include the Old World blackbird, the yellow-headed blackbird, and the grackles. Although crows and ravens also have black feathers, they do not belong to the blackbird family.
Where blackbirds live
Blackbirds make their nests in marshes, on dry prairies, or in dense evergreen forests. The Old World blackbird lives in woods and gardens throughout the warmer areas of Europe and Asia as well as in New Zealand and Australia. Most blackbirds, however, are found in North America. Red-winged blackbirds live in cattail marshes from Canada to the West Indies and Central America. The yellow-headed blackbird of the Western plains also nests in marshes. Grackles are found along the southern coasts of the Atlantic Ocean and the Gulf of Mexico.
Physical features
Blackbirds generally range from 8 to 16 inches (20 to 41 centimeters) in length. Red-winged blackbirds are about 8 inches (20 centimeters) long. Old World blackbirds are about 10 inches (25 centimeters) long. At about 16 inches (41 centimeters) and with a long tail, the male great-tailed grackle is the largest of the blackbirds.
Though the males are mostly black, blackbirds boast a variety of colored details. The male red-winged blackbird has yellow and red feathers on its shoulders. The female is brown and resembles a large sparrow. Male Old World blackbirds are all black, and the females are brown. Both have an orange bill and orange coloring around the eyes. The male yellow-headed blackbird has a bright yellow head and a black body; the female has a dull yellow head and gray-brown body. The male great-tailed grackle has black feathers with a purple or blue-green shine.
Behavior
Many blackbirds make loud squeaks and gurgling clucks while fluttering their wings, bobbing their bodies, and wagging their tails. Red-winged blackbirds chirp musical songs.
Most blackbirds eat insects. Blackbirds are a benefit to humans because they eat harmful insects such as crop-eating pests.
Blackbirds have a variety of nesting habits. Some build nests on the ground, others attach theirs to marsh plants, and some build them high above the ground in trees. Some blackbirds, including the tricolored blackbird and the common grackle, build their nests in colonies. Both the male and the female usually help feed the young.
One of the earliest voices of spring in North America is the bluebird's. Bluebirds got their name from the males' bright blue feathers. All bluebirds belong to the thrush family; different species, or types, include the common, mountain, and western bluebirds. The common bluebird is the state bird of Missouri and New York.
Where bluebirds live
Bluebirds are found in fields, orchards, and gardens in North America. Common, or eastern, bluebirds live east of the Rocky Mountains, from northeastern Canada to the state of Florida. During the winter months, they migrate south to the middle states and the coast of the Gulf of Mexico. The mountain, or Arctic, bluebird can be found in the mountains of western North America. In winter, mountain bluebirds live in the southern United States and Mexico. The western bluebird lives from western Nevada and Idaho to the Pacific coast and north to British Columbia. It spends its winters in Mexico.
Physical features
Bluebirds are about 7 inches (18 centimeters) long. The males are usually more colorful than the females. Different kinds of bluebirds have slightly different colors. Most males are blue with a chestnut-colored throat, breast, and sides. Females can be grayish blue or brownish gray.
Behavior
Bluebirds nest in enclosed spaces, such as a hollow tree, an abandoned woodpecker hole, a rotted fence post, a bird box, or even a mailbox. Bluebirds line the bottom of their nests with dry grasses. The female lays four to six bluish white eggs at a time.
Bluebirds eat mostly insects and some fruit. Their diet makes them helpful to farmers because they keep harmful insects away from crops.
The boa constrictor is a large snake that kills its prey by coiling around it so tightly that it cannot breathe. Despite this deadly strength, the boa constrictor has gained popularity as a pet because it is mild-mannered, easily tamed, and not poisonous. They are so well behaved that some farmers even keep them around their fields, barns, and storage bins to hunt the rats and mice that eat their grain.
Where boa constrictors live
Boa constrictors live in a variety of habitats throughout Central and South America, including both tropical rainforests and dry scrublands and grasslands. The largest boa constrictors are found in South America.
Physical characteristics
The thick, muscular bodies of boa constrictors grow to about 10 feet (3 meters) in length, but some have been measured at more than 18 feet (5.5 meters). Central American boas rarely reach a length of more than 8 feet (2.4 meters). Some boa constrictors may be red or silver. However, most have a brown and gray body marked with a pattern of brown and black triangles and ovals, with white borders and streaks. The long, triangular head of a boa constrictor has dark streaks from the eyes to the back of the jaw and another dark streak along the top.
Behavior
During the day the boa constrictor rests in tree hollows, old logs, and animal burrows. At night it hunts a wide variety of birds, reptiles, and mammals. It hunts most animals on the ground, but it also climbs into trees in search of birds.
Females give birth to litters of live young that measure from 1 to 2 feet (0.3 to 0.6 meter) long. Litters may include several dozen babies.
One of the tallest of all dinosaurs, Brachiosaurus was built something like an enormous elephant with an extremely long neck. This dinosaur was tall enough to have looked over the top of a modern four-story building. The name Brachiosaurus means “arm lizard” in Latin. Scientists call it this because of its long front legs. Brachiosaurus belongs to the group of dinosaurs known as sauropods, which also includes Apatosaurus and Diplodocus. The sauropods were large, plant-eating dinosaurs with long necks, massive bodies, and four pillarlike legs to support the body.
Where and when Brachiosaurus lived
Brachiosaurus lived about 150 to 130 million years ago, in the late part of the geologic period known as the Jurassic and the early part of the Cretaceous. Remains of Brachiosaurus have been found in Europe and Africa, as well as in Colorado, Wyoming, and Utah in North America. Scientists once believed that Brachiosaurus, like other large sauropod dinosaurs, needed to live in water to support its massive weight. They now agree that Brachiosaurus was primarily a land animal. Its strong but lightweight bones were able to support it without the help of water. Brachiosaurus lived in areas with much plant life, especially tall trees.
Physical features
Brachiosaurus is the largest and heaviest sauropod dinosaur for which a complete skeleton has been discovered. This dinosaur could reach more than 75 feet (23 meters) in length and weighed up to 80 tons. It stood about 43 feet (13 meters) tall from its head to the ground. The most striking features of Brachiosaurus were its sloped back and its extremely long neck. Its front legs were longer than its back legs, which was a unique feature among dinosaurs. Brachiosaurus also had a relatively short tail. Its dome-shaped head was small and its snout was somewhat flat. Its nostrils were fairly large and were located near the top of its head. Brachiosaurus had a few dozen pencil-like teeth.
Behavior
Brachiosaurus was a plant-eating dinosaur. Its long neck allowed it to feed from the tops of the highest trees, where other dinosaurs could not reach. Scientists believe that Brachiosaurus also fed on low-lying ground plants, such as ferns. Like other sauropod dinosaurs, Brachiosaurus had small stones in its stomach to help it grind up the plants that it ate. Brachiosaurus lived and traveled in herds. Scientists believe that Brachiosaurus could travel at speeds of about 12 to 19 miles per hour (19 to 31 kilometers per hour). Its immense size and weight, as well as sharp claws on its feet, protected it from meat-eating dinosaurs. Its tremendous height also allowed Brachiosaurus to watch for enemies coming from miles away. Young Brachiosaurus probably stayed in the center of the herd for protection. Brachiosaurus, like most other dinosaurs, reproduced by laying eggs.
Although the North American bison is often called a buffalo, true buffalo come from much warmer lands in Asia and Africa. Along with bison, buffalo belong to the scientific family Bovidae.
Where buffalo live
The several types of buffalo are native to South and Southeast Asia and much of Africa. As people from those regions spread throughout the world they brought buffalo with them. Today the animals can be found in Europe, Australia, and South and Central America as well as Asia and Africa.
The Indian, or Asian water, buffalo lives in tall grasses close to bodies of water. It loves to lie in water or wallow in mud to keep flies away as well as to keep cool. The Cape, or African, buffalo lives in open or scrub-covered plains and open forests. Other types live in dense forests.
Physical features
Buffalo are heavily built animals. They range in size from the anoa, which stands about 3 feet (1 meter) tall, to the Asian water buffalo, which can reach a height of more than 5 feet (1.5 meters). All buffalo have horns, although the size and shape of the horns can vary greatly. The Cape buffalo has heavy horns that typically curve downward, then up and inward; in males the two horns meet to form a shield that covers the whole top of the head. The Asian water buffalo has horns that curve outward and backward and may reach 4 feet (1.2 meters) across. The animals can also vary in color. Many are black, though they may have patches of white, and one African type is reddish in color.
Behavior
Except for the anoa, buffalo in the wild travel and live in herds. They spend a great deal of time grazing on grasses and digesting their food. Buffalo are ruminants, which means that they digest their food by swallowing it, regurgitating it (bringing it back up from the stomach), and then chewing it again in a form called cud. Female buffalo give birth to one or two young 10 or 11 months after mating.
Buffalo and humans
The Asian water buffalo has been domesticated, or tamed for use by humans, for thousands of years. People value it as a beast of burden that can pull or carry things on its broad back. It is accustomed to wet conditions and for that reason is employed in flooded rice fields. People use buffalo milk and meat for food. In addition, people make leather products from buffalo hides.
Though the domestic water buffalo remains widespread, the number of buffalo in the wild is decreasing. Farmers have taken over some of the lands where wild buffalo live. Humans have hunted the animals in large numbers for food and for their hides. Diseases spread by domestic animals have also decreased the population of wild buffalo.
Zebra swallowtail butterfly
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Luna moth
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Known for their brightly or strikingly colored wings, butterflies and moths are flying insects that come from caterpillars. There are as many as 100,000 different types of butterflies and moths throughout the world.
Where butterflies and moths live
Butterflies and moths are found in temperate regions, snowy mountains, deserts, and jungles. In fact, butterflies and moths live on every continent except Antarctica.
Physical features
Like all insects, butterflies and moths have three pairs of legs. Their bodies are divided into three sections: the head, thorax, and abdomen. On either side of the head is a large compound eye. The compound eyes are very efficient for distinguishing movement. They cannot, however, see distant objects clearly. Some butterflies and moths have very sharp hearing and sense of smell. They also have a good sense of taste, especially for sugars.
There are two pairs of wings on the thorax, or middle section of the body. The pair in front is usually the larger of the two. The wings, body, and legs are all covered with dustlike scales that come off when handled.
Butterflies and moths vary greatly in size. The smallest moths have wing expanses as small as about 16100 inch (4 millimeters), while the largest have wingspans of about 1 foot (nearly 30 centimeters).
Although butterflies and moths have similar appearances, they are different from each other in many ways. The best way to tell them apart is to examine their antennae, or feelers. Butterfly antennae are slender, and the ends are rounded into little knobs. Moth antennae lack these knobs. Moth feelers may look like tiny feathers, and some are threadlike.
Butterflies are usually brightly or strikingly colored. Most moths have a duller color, a stouter body, and smaller wings than butterflies. Butterflies rest with their wings held upright over their backs; moths rest with their wings outspread. Most butterflies fly during the daytime, while moths generally fly at night.
Skippers are insects that have some characteristics of both butterflies and moths. Their bodies resemble moths. When at rest, however, they hold their wings upright like butterflies. Skippers are generally small. They get their name because they fly with quick movements from place to place.
Behavior
Butterflies and moths feed on the nectar of flowers and on other plant liquids. Some species eat mosses, ferns, and lichens. Others may feed on cones and fruits and their seeds. Many also feed on dead and decaying plant matter.
Some butterflies and moths are famous for the fact that they travel from place to place. Several species in Europe and North America migrate to different regions based on the seasons. In North America the monarch butterfly lives as far north as southern Canada during the summer. In the fall these butterflies travel to California or Mexico, where they spend the winter. They then return to their summer homes in the spring. Unlike birds, they do not make the trip more than once since butterflies do not live longer than a year.
Life cycle
Butterflies and moths go through four stages of development: egg, larva (caterpillar), pupa (chrysalis), and adult (imago). The process of changing from one stage to the next is known as metamorphosis.
First, the female lays many eggs. Caterpillars hatch from these tiny larvae. The caterpillar then sheds its skin many times in a process called molting, until it is ready to turn into a pupa. The pupa is a resting stage, where the future butterfly lies encased in a tough, flexible shell. During this stage the organs and other tissues of the caterpillar break down and are replaced by wings, legs, and other parts of the adult.
In the final stage, the adult emerges from the pupa. At this point it is wet and its wings are soft and limp. It slowly fans the wings to pump air into the veins. Gradually the wings expand and harden. In a few hours the adult is ready to fly and seek a mate. Most adults live from four to six weeks. Some live only a few days, while others may live as long as ten months.
Defenses
Butterflies and moths have many enemies. In fact, they are a favorite food of birds. To survive, some species have natural protections. For example, the monarch butterfly has a foul taste and odor and is avoided by birds. The viceroy butterfly looks exactly like the monarch, only smaller. Because birds mistake viceroy butterflies for monarch butterflies, the birds leave the viceroy butterflies alone too.
Other species have unusual markings that frighten away birds. In addition, many butterflies and moths at rest look like dead leaves or the twigs and bark of trees. Therefore, they are difficult for birds to spot.
Buzzards are carnivorous birds, which means that they eat other animals for food. They are in the same family of birds as hawks and are considered birds of prey. The best-known buzzard is the common or true buzzard.
Where buzzards live
The common buzzard is found from Scandinavia in the north to the Mediterranean Sea in the south. Other species, or kinds, range over much of North America, Eurasia, and northern Africa. They live in hills, wooded valleys, and farmland with scattered woods.
Physical characteristics
When in flight, buzzards can be recognized by their broad wings and large rounded tails. Their wingspan may be anywhere between 48 and 60 inches (120 to 150 centimeters). They fly with slow, heavy wing beats and soar gracefully. The feathers of most buzzards are dark brown above and white or light brown below. The tail and underside of the wings are usually striped. The color of these birds varies.
Behavior
Buzzards eat insects and small mammals. They also occasionally attack other birds. They are slow fliers, so they do not usually catch their prey on the move. Instead, buzzards perch motionless on a branch while waiting patiently for a rabbit, rat, or mouse to pass beneath it. Then they swoop down and surprise their prey.
Buzzards build big nests, usually in a tree or on a cliff. They build these nests with sticks and line them with softer materials. They generally lay two to five eggs. The eggs are white and brown.
Sometimes called the “ship of the desert,” the camel is a large mammal that is well suited to living and working in hot, dry deserts. Camels are known for their humps, which can nourish the animal for several days when it does not have food or water.
Where camels live
Camels originated in North America about 40 million years ago. By about 1 million years ago they had spread to South America and Asia. Camels later vanished from North America. Relatives of the camel, such as the guanaco, vicuña, llama, and alpaca, now live in South America.
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The Bactrian, or Asian, camel is found throughout the highlands of Central Asia. Although this camel is largely domesticated, or tamed to help humans, small herds of wild Bactrians are still found in southwestern Mongolia and northwestern China.
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The dromedary, or Arabian, camel is found in North Africa, the Middle East, and India. This camel once roamed wild but is now found only in domestication. Groups of dromedaries, however, are often left on their own for up to five months. The dromedary has been imported into many parts of the world, including the United States and Australia.
Physical features
The camel's most striking feature is the large hump (for the dromedary) or two large humps (for the Bactrian) on its back. The hump is made of fat and muscle and does not have any bone. When a camel is well fed and given enough water, the hump remains erect. If the animal goes without food and water for a period of time, the fat in its hump can nourish it for several days. In this case, the hump becomes limp and leans to one side.
When a camel stands on its very long legs, its hump can reach a height of 7 feet (about 2 meters) above the ground. The animal weighs up to 1,500 pounds (680 kilograms). It has a long, thin neck, a small head without horns or antlers, and a split upper lip. Each foot consists of two toes. Each toe has a hoof at end of it. The soft feet are well suited for walking on sand or snow. Horny pads on a camel's chest and knees support its weight when it kneels. The camel's body is covered with a scruffy, sand-colored coat of hair. A thick fringe of hair also hangs from the long, curved neck.
Camels are well adapted to the desert and other harsh environments. A long, double row of eyelashes protects the animal's eyes from sandstorms and the glare of the desert sun. The nostrils can open wide to draw breath, or they can close to keep out blowing sand. The camel also has a keen sense of sight and smell. It has long jaws with sharp teeth. A camel's lower jaw swings sideways as the animal chews.
Behavior
Camels can survive on the coarsest of vegetation. They can feed on thorny plants, the leaves and twigs of shrubs, and dried grasses. They can also go for days or even months without water. Camels can carry up to 1,000 pounds (450 kilograms), though a more typical load is about one third of that.
Life cycle
The female camel produces one calf at a time. The newborn calf stands about 3 feet (1 meter) high on long, thin, wobbly legs. It can follow its mother to pasture just one day after birth.
By their third year camels have grown big enough to carry heavy loads. They can bear such loads for 15 to 20 years and then do lighter work until they are about 30 years old. The life span of a camel is generally 30 to 40 years.
Other uses of the camel
Camel milk and meat are valuable sources of nourishment for desert dwellers. Camel hair can be used to make tents, blankets, rugs, clothing, rope, and cord. Dried camel droppings are useful as fuel for cooking fires. The hide of the animal can be used for making sandals, water bags, and other necessary articles.
A canary is a type of bird that belongs to the finch family. It has become a popular household pet around the world. Canaries became cage birds in the 16th century, when they were first brought from the Canary Islands of Spain to Italy. Over time, humans have been able to breed at least 50 different kinds of canaries.
Where canaries live
The canary is native to the Canary, Azores, and Madeira islands. In North America, “wild canaries” are also known as American goldfinches and yellow warblers. Both of these birds look like pet canaries. Breeders in the United States, France, Belgium, England, and Scotland have helped develop the canary's color, shape, and song.
Physical features
In the wild, canaries measure about 5 12 inches (14 centimeters) in length. They are dull green with a yellow breast. Canaries kept as pets differ in size, form, feather color, and song. Breeders work to develop these characteristics among the different kinds of canaries.
The American Singer is a very popular type of canary. It is usually yellow. One of the most graceful canaries is the Yorkshire canary. It has a long, slim body. The average life span of a caged canary is ten to 15 years.
Behavior
The behavior and song of a canary vary depending on the type of breed. A roller canary trills almost continuously, and its songs are very controlled and complex. Another kind of canary, called a chopper, has a loud trill.
A songbird of the finch family, the cardinal is sometimes called the redbird because of its striking color. Its loud, clear whistling song can be heard year-round in gardens and open woodlands. The cardinal is the state bird of Illinois, Indiana, Kentucky, North Carolina, Ohio, Virginia, and West Virginia.
Where cardinals live
Cardinals are found in North America east of the Rocky Mountains. They are especially abundant in the southeastern United States. Over the years, their range has extended farther into the northern United States. Cardinals do not migrate but instead spend the winter in their nesting areas.
Cardinals like brushy thickets and tangles. However, they also live in urban areas where shrubbery offers protection. They usually build their nests in bushes within a few feet of the ground. These nests are loosely built structures of twigs, leaves, bark, and grasses.
Physical characteristics
The cardinal is about 8 inches (20 centimeters) long, a little smaller than a robin. The male is easy to identify with its red crest and feathers and black face markings. The female and young have gray-brown backs and dull red wings, tail, and crest.
Behavior
Cardinals feed on insects and thus are good for pest control. They also eat seeds and wild fruits.
Female cardinals lay two to four eggs. They are bluish white with brown spots and hatch in 12 days. Baby cardinals remain in the nest for about ten days. The male cares for the young after they leave the nest, while the female prepares for the next family.
Cats have fascinated humans for thousands of years. People have prized them as hunters and companions, worshiped them as gods, and sacrificed them as demons. They often have been used as symbols of beauty, grace, mystery, and power. Cats are members of a flesh-eating family of animals that includes the lion, tiger, jaguar, leopard, puma, cheetah, and domestic cat, or house cat. The domestic cat (species Felis catus) is a member of the larger cat family Felidae. This article discusses the domestic cat.
Form and structure
Members of the cat family are quite easy to identify. They differ widely in size, color, and markings, but they all look “catlike.” They have long, rather slender but powerfully built bodies. Domestic cats are very different from the larger cats, in coat as well as in size. Male domestic cats may reach 28 inches (71 centimeters), but 21 inches (51 centimeters) is a more usual length for females. Most female domestic cats weigh between 6 and 10 pounds (2.5 and 4.5 kilograms) while males weigh between 10 and 15 pounds (4.5 and 6.8 kilograms). The British shorthair cat may weigh up to 28 pounds (13 kilograms). Most house cats, including the Siamese and Abyssinian, are shorthaired, but the Persian has a long, thick coat. The rex, a British breed, has a curly coat. The domestic cat may be black, white, brown, gray, yellow, red, orange, stripped (tabby), mixed white, black, and yellow (tortoiseshell), or marked with patches of color (calico).
Claws and teeth
The cat is equipped to be an efficient hunter. It has strong, sharp retractile claws, which are capable of being drawn back or in, and strong, sharp teeth. The jaws of a cat are short but they, too, are extremely strong. They clamp down upon prey with enough power to crush bones. The cat's teeth are used to grab and hold prey. The sharp molars function like scissors and cut food into small pieces.
Eyes, ears, and whiskers
The cat's large and prominent eyes are placed well forward on the head. The size and position of the eyes permit as much light as possible to enter them, which ensures a large field of vision—important for hunting and night prowling. The cat's hearing also is extremely sensitive. The triangular ears can rotate rapidly to identify the source of a sound. A cat can detect many sounds that humans cannot hear. In the cat, as in humans, the inner ear contains a mechanism for maintaining body balance. It is this mechanism that lets the animal land on its feet when it falls.
A cat's whiskers serve as delicate sense organs of touch. They allow the cat to feel its way around. Four rows of stiff whiskers grow on the upper lip on each side of the nose. Small groups of whiskers also grow on other parts of the body including above each eye, on both cheeks, and on the backs of the front paws.
The tongue
A cat's tongue is rough. The tongue of a domestic cat feels much like sandpaper. The tongue of a big wild cat, such as a lion or a tiger, is much rougher. The surface of the tongue is covered with small hooks, or barbs, that face backward into the throat. All cats use their tongues as grooming tools to clean and comb the fur. They also use them as tools to strip flesh off the bones of prey.
The purr
All cats—domestic and wild—can and do purr. The sound may be very loud or very soft. Kittens may begin to purr a few days after birth. In all animals, vocal sounds come from vibrations of the vocal cords, which are in the voice box in the throat. No one knows exactly how the cat uses its vocal cords to produce purring nor why no other kind of animal purrs. In addition to purring, cats make several different kinds of sounds—including meowing, chirping, hissing, yowling, and even growling.
Life cycle
A female cat may have two to three litters of young (kittens) a year. A domestic cat carries the unborn kittens inside her body for about 64 days. As the time for birth approaches, she hunts for a quiet, safe place to have her kittens. The average litter consists of four kittens but there may be only one or as many as seven. A newly born kitten weighs about 3.5 to 5 ounces (100 to 142 grams) and is about 3 inches (8 centimeters) long.
At the time of birth the kitten has no teeth, the eyes are closed, and the fur is soft and downy. The ears lie flat against the head and the tail is short and triangular. The kitten begins to get its first teeth when it is two or three weeks old. The eyes begin to open when the kitten is about 8 to 12 days old. Kittens begin to crawl out of their nest when they are about a month old. The rate of growth depends on what kind of cat it is and nutrition. Most six-month-old domestic cats weigh about 5 pounds (2.3 kilograms). Their full development takes about one year. Female cats usually become sexually mature when they are six to eight months old, and males become sexually active a few months later. A simple operation, called spaying or neutering, prevents overpopulation by removing the cat's ability to reproduce.
History
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Bombay
The first association of cats with humans may have begun toward the end of the Stone Age, some 10,000 years ago. About 4,500 years ago cats were considered sacred in Egypt. The Egyptians used the cat to hunt fish and birds as well as to destroy the rats and mice that infested the grain stocks along the Nile River. Domestic cats were also found in India, China, and Japan where they were prized as pets as well as rodent catchers. However, during the Middle Ages in Europe, the cat became an object of superstitions and was associated with witchcraft. Cats were hunted and tortured. A trace of those superstitions exists even today in the fear some have that a black cat is an unlucky omen.
Historically, dogs were the most popular pet in the United States. By the turn of the 21st century, however, the number of cats as pets outnumbered dogs.