The Complete List Of Animals

[Scientist]

The most commonly displayed dinosaur in museums is Diplodocus. This dinosaur was longer than a tennis court and is the longest complete dinosaur that scientists have discovered. The name Diplodocus means “double beam.” This name comes from a special feature of its tail bones. Diplodocus belongs to a group of enormous dinosaurs called sauropods. The sauropods were large, plant-eating dinosaurs with long necks, massive bodies, and four pillarlike legs to support the body.

Where and when Diplodocus lived
Diplodocus lived about 159 to 144 million years ago during a period of the Earth's history called the Jurassic. Remains of this dinosaur have been found in North America, especially in Colorado, Montana, Utah, and Wyoming. Diplodocus lived in meadows where plants grew thick and at the edges of forests and other areas where many trees grew.

Physical features
Scientists refer to Diplodocus as a walking suspension bridge. Its four legs were built like supporting pillars, and its spine held up its body, just as a bridge with cables holds up a road. Diplodocus measured up to 90 feet (27 meters) long and stood about 15 feet (4.6 meters) tall at the hips. A lightweight among the sauropod dinosaurs, Diplodocus weighed only about 30 tons. The unique, hollow structure of its backbones helped this animal to be so light. It had a long neck and a very long tail. Diplodocus had a small, horselike head and a very small brain. It had peg-shaped teeth in the front of its mouth. Its back legs were slightly longer than its front legs, making the animal slope downward from its hips to its head. Diplodocus had elephantlike feet with three claws on each back foot. One section of its tail bones featured a pair of anvil-shaped projections on the underside of each bone in that section. Scientists believe that these bones served as protection for the blood vessels and tissues of the tail. These are the “double beams” for which the dinosaur is named. Scientists once thought that Diplodocus dragged its tail along the ground. They now agree that this dinosaur held its tail high off the ground. It may have used its tail as a whip in self-defense.

Behavior
Diplodocus was a plant eater. It may have fed on low-lying ferns, though its long neck also allowed it to browse the tops of trees. Some scientists think that Diplodocus actually stood up on its back legs to reach the treetops. Its specially designed tail with the “double beam” bones may have acted as an extra leg for the animal to lean back on. Diplodocus had no back teeth to chew with, so it swallowed small stones to help grind up the plants in its stomach. Diplodocus lived and traveled in herds. It reproduced by laying eggs.

[Scientist]

The dog is one of the most popular animals in the world. It was among the first animals to be domesticated, or trained for use by humans. It is characterized by loyalty, friendship, protectiveness, and affection. Therefore, dogs are also known as man's best friend.

Physical characteristics
Domestic dogs vary in size depending on their breeds. A small Mexican Chihuahua can weigh just over 1 pound (around 500 grams), whereas the Great Dane can weigh as much as 130 pounds (60 kilograms). Dogs grow to various heights. The Irish wolfhound stands about 32 inches (81 centimeters) high at the top of its shoulders. The chihuahua stands about 5 inches (12 centimeters) high.

Dogs, like humans, have five senses. Their sense of smell is very sharp. A dog continually sniffs the air, the ground, and nearby objects to learn what is happening around it. Some breeds, such as the German shepherd and the bloodhound, have a much sharper sense of smell than others. Because of this, these breeds are used to track explosives, drugs, and missing persons. Dogs also have a fine sense of hearing. They can detect noises well beyond what people can hear.

The eyesight of a dog is not as keen as its sense of smell. It is generally thought that dogs are poor at identifying color differences. Dogs can generally see better in dim light than humans but not as well in bright light. They have a wider range of vision than humans because their eyes are set further toward the sides of their heads. However, dogs are not as good at focusing on objects at close range or at judging distances.

The dog's foot, or paw, has five toes. One of them, the dewclaw, is too high to be of any use. A toenail, or claw, emerges from the end of each toe. The foot also has cushiony pads for each toe and two larger pads farther up the paw.

The thin tongue of the dog is used mainly for guiding food to the throat, for licking the coat clean, and for perspiration. When a dog is overheated, it cools off by hanging its tongue out and panting. As it pants, the perspiration evaporates from its tongue and cools the animal. The dog also sweats through the pads on its paws and slightly through its skin.

Behavior
The dog is a social creature. It prefers the company of people and of other dogs. Therefore, it is considered to be a pack animal. Dogs claim territory and mark it as its own. Dogs indicate their area by urinating and rubbing their scent on the ground or on trees as a sign of their presence.

Dogs are capable of a wide range of responses to their environment. For example, when a dog meets another dog and its ears are erect, it is concentrating on the other dog. If its ears are pointing forward, it is on the alert. If a dog holds its tail high and wags it, the animal is happy and confident. If it drops its tail and remains still, the dog is anxious. If it pulls its tail between its legs, the dog is afraid. If on meeting a person or another dog it pulls back its lips and growls, it is making a threat.

Breeds
It is estimated that there are about 400 purebred dogs worldwide. For a puppy to be purebred, father and mother must be of the same breed. A mongrel dog is one with many breeds in its background.

Throughout the years, dogs have been bred for the purposes of hunting, herding, and guarding. Dogs such as the Doberman pinscher and the German shepherd serve as alert and aggressive watchdogs. Others, such as the beagle and the cocker spaniel, are playful family pets, even though they were originally bred for hunting. Some others, such as the collie and the Welsh corgi, can herd farm animals.

The American Kennel Club recognizes seven groups according to their original functions. These groups are sporting dogs, hounds, working dogs, terriers, toys, non-sporting dogs, and herding dogs. Sporting dogs hunt, locate, and retrieve game birds. Hounds hunt all game except birds. Working dogs can do jobs such as water rescues, pulling sleds and carts, and guarding life and property. Herding dogs control the movement of other animals. Terriers were once bred to hunt rodents but are now bred as house pets. Toys are tiny dogs bred mainly as pets. Non-sporting dogs are those purebreds that do not fit in the other categories.

Of the wild dogs one of the most important is the dingo, found in Australia. However, dingoes are rarely seen outside of zoos. Efforts are being made to protect them in the wild. Another, the dhole of India, is said to be a fierce, untamable dog.

Life cycle
The puppy grows inside the mother for 63 days before its birth. Puppies are born blind and deaf. They are totally dependent on the mother for warmth and nourishment. Between 10 and 14 days after birth, their eyes and ear canals open. The puppies then begin to move around actively. As they grow, they become more curious and start to investigate their surroundings. Between 12 and 16 weeks, the puppy becomes independent of its mother and starts exploring new territories.

The average life span of a small- and a medium-sized dog is 15 years. A large dog lives only up to the age of 10.

Dogs and humans
Dogs have been with humans since prehistoric times. Over the years they have performed various services. Dogs have also served as a source of food. In the past, dogs have even been worshiped as gods.

The ancient Romans relied on watchdogs. So many dogs were kept in the larger Roman cities that any house with a watchdog was required to have a warning sign, “Cave Canem,” or Beware of the Dog. The Romans also used dogs for military purposes, sometimes as attack dogs and sometimes as messengers.

Toy dogs were popular among the ancient Chinese. The little animals were used to provide warmth when carried in the wide sleeves of the gowns.

Recently, dogs have been used in drug research and scientific experimentation. Soviet scientists launched dogs into space to test the ability of mammals to survive there. Specially trained dogs serve as the “eyes” of the blind, guiding the steps of their sightless masters around obstacles and hazards.

[Scientist]

Known for their intelligence, playfulness, and friendliness toward humans, dolphins can often be seen swimming alongside boats or performing at aquariums. Dolphins look like large fish, but they are actually small whales. Like whales and other mammals, they breathe through lungs instead of gills and give birth to live young, among other typical traits.

Dolphins are closely related to another group of small whales, the porpoises. Because dolphins and porpoises look so much alike, the two are often confused with one another. In fact, the names dolphin and porpoise are sometimes used as if they are one and the same. In general, however, dolphins can be told apart from porpoises by their larger size and their snouts. A dolphin has a long, sharp snout that is flattened like a beak. A porpoise's snout is short and blunt (see porpoise). The name dolphin is also sometimes used for a large fish known as the mahimahi or dorado. As a fish, the mahimahi differs from the mammals more commonly thought of as dolphins.

Where dolphins live
Dolphins can be found throughout the world in either salt water or freshwater. The most widespread species, or kinds, are the common and bottle-nosed dolphins. Both live in warm and temperate oceans and seas worldwide. River dolphins are found only in South America and Asia. They prefer freshwater.

Physical features
The larger dolphins, including the bottle-nosed species, can reach a length of 13 feet (4 meters). Most dolphins, however, are 7 to 10 feet (2 to 3 meters) long. They have smooth, rubbery skin and are usually colored in some mixture of black, white, and gray. A layer of fat beneath the skin, known as blubber, helps keep them warm in the water. Dolphins have two flippers, which are fins that serve as forelimbs, as well as a triangular fin on the back.

Like other mammals, dolphins are warm-blooded. This means that they keep their body temperature about the same even when the temperature of their surroundings changes. Because a dolphin breathes through lungs, it must come up to the water's surface to breathe. A single nostril, called a blowhole, on the top of a dolphin's head lets air move in and out.

Behavior
Dolphins are social animals, meaning that they generally live in schools, or groups. Sometimes these schools are made up of as many as 1,000 individuals. Dolphins use a range of sounds to communicate with each other and often act together to achieve a goal, such as trapping fish to eat. They have been known to help an injured dolphin by pushing it to the surface so it can breathe.

Dolphins also use sounds to find objects underwater. A dolphin lets out whistles and squeaks that are too high-pitched to be heard by humans. These sounds reflect off solid surfaces and then travel back to the dolphin's sensitive ears. The time it takes for a reflected sound to return tells the dolphin how far away something is. This process is called echolocation. It is especially helpful for river dolphins, many of which live in muddy water.

Dolphins are intelligent animals with great learning abilities. They have been trained to perform impressive tricks in aquariums, including high leaps above the water. Their speedy and graceful swimming adds to their appeal as performers.

Reproduction in dolphins usually takes place in the warm months. After a pregnancy of about 10–12 months, a female dolphin gives birth to a single offspring. A newborn dolphin, called a calf, looks like a smaller version of its parents. Just after birth the mother nudges the calf toward the surface of the water so that it can take its first breath of air. Dolphin mothers provide milk for their young for a year or longer. The length of time a dolphin lives varies by species, but some have survived more than 30 years.

Survival issues
Bottle-nosed dolphins and other species used to be hunted in large numbers for their meat and for other reasons. Many countries have banned dolphin hunting, but the practice continues in some places. Nets set in the ocean to catch tuna and other fish are another threat to dolphins. Dolphins swim into these nets and become trapped. To prevent dolphins from being injured or drowning in the nets, some of them are now made with exits that allow dolphins, but not fish, to escape. Another danger is pollution of the world's oceans. The dumping of chemicals and other wastes into the water may poison the dolphins' food supply and make the dolphins sick.

[Scientist]

A descendant of the African wild ass, the donkey belongs to the horse family. The words donkey and ass are used to identify the same animal. However, the term ass is more often used when the animal is wild, and the term donkey is used when the animal is domesticated, or tamed so that it is useful for humans.

Where donkeys live
The donkey is believed to be originally from Southern and Central Asia, but it is now used as a working animal around the world. For example, donkeys are used in the mountains of Ethiopia and other parts of Northeast Africa, the high plains of Tibet, and the dry regions of Mongolia.

Physical features
The average donkey stands 40 inches (102 centimeters) at the shoulder, but different breeds vary greatly in size and shape. The Sicilian donkey reaches only about 24 inches (61 centimeters), while the large ass of Majorca stands at about 62 inches (158 centimeters). The American ass can reach a height of about 66 inches (168 centimeters). Donkeys range from white to gray or black in color. They usually have a dark stripe from the mane to the tail and a crosswise stripe on the shoulders. The mane is short and upright and the tail has long hair only at the end. The very long ears are dark at the base and tip.

Although the names donkey and burro can be used to mean the same thing, the term burro is widely used in the southwestern United States to describe small donkeys. Burro is the word for donkey in Spanish.

Behavior
The donkey usually feeds on coarse food. It is a patient and hardworking animal. The donkey responds to gentle treatment with affection and shows attachment to its master. Although considered stubborn and slow, a donkey can carry heavy loads over rough land. The donkey can handle the uneven ground of the mountains better than a horse can.

The male donkey, also called a jack, can be mated with a mare (female horse) to produce the sturdy mule. The female donkey, or jennet, can be mated with a stallion (male horse) to produce the hinny. Mules and hinnies cannot reproduce. The mule is used for farm work and as a baggage animal for carrying equipment on expeditions. In subtropical and tropical countries mules are used because of their ability to withstand heat and irregular feeding.

[Scientist]

In the wild or raised by people, ducks are familiar birds around the world. About 40 species, or types, live in North America alone. Ducks, geese, and swans are known as waterfowl in North America and wildfowl in Europe. Ducks are the smallest of the waterfowl.

Where ducks live
Ducks live on the water or close to it. They are found on and around all continents except Antarctica. There are freshwater ducks and saltwater ducks, ducks of coastal waters and ducks of the open sea. Many ducks are migratory, meaning that they travel long distances for different seasons. Northern ducks, for example, fly south for the winter.

Physical features
Ducks are like geese and swans in many ways. All three kinds of waterfowl have large bills and webbed feet. Their bodies are protected from cold by soft inner feathers called down. Their outer feathers are protected from water by oil that comes from a gland near the tail. But ducks are smaller than the other waterfowl, and they have shorter necks in proportion to their bodies. The legs of ducks are positioned to move the bird smoothly through water, which is why ducks waddle comically on land.

Ducks vary in size and color. The familiar mallard of North America, Europe, and Asia is about 24 inches (61 centimeters) long, including the tail. Mallards usually weigh less than 3 pounds (1.4 kilograms). Male ducks, known as drakes, are often much more colorful than the females. The males of the wood duck and mandarin duck species have especially splendid feathers.

Behavior
Ducks can be grouped according to their feeding and nesting behavior. Those that feed by dipping the head below the surface while tipping up the tail are called dabbling ducks. Dabbling ducks live in marshes, shallow ponds, and slow-moving streams. They feed on the water plants, shellfish, and insects that they find in the shallows. Some of them also feed on land. The mallard is the best known of the dabbling ducks. The black duck of North America and the teals, wigeons, pintails, and shovelers are also dabbling ducks. Dabbling ducks that nest in trees are called perching ducks. The wood duck of North America, the mandarin duck of China, and the big muscovy duck of South America are perching ducks.

Ducks that dive far below the surface are known as diving ducks. Some diving ducks are sea ducks. These ducks feed mostly on fish and sometimes sleep on the water. Mergansers, scoters, goldeneyes, and eiders are among the sea ducks. Other diving ducks stay close to the shore and are called bay ducks, or pochards. The canvasback is a bay duck that eats mostly water plants. Other bay ducks, such as the scaup, prefer shellfish. Not all diving ducks are saltwater birds. The stifftail group includes many freshwater divers. The ruddy duck is the most familiar North American stifftail.

Dabbling ducks nest mostly in northern regions and fly south in autumn. They are fast fliers. By contrast, some of the diving ducks of South America cannot fly at all. They are called steamer ducks because they run on the water with their wings churning like the paddles of old-fashioned steamboats. Other diving ducks, such as the ruddy duck, find it almost impossible to walk on land.

Life cycle
Most ducks make their nests on the ground, near water. They use plants, grass, and down from their own bodies to line the nest. Once the eggs are laid, the drake has nothing more to do with raising the family. The female tends the 6 to 12 eggs, keeping them covered with down while she is away from the nest. The eggs hatch into fluffy ducklings in about 20 to 25 days.

The ducklings can feed themselves and swim soon after birth. Within a day or so, their mother leads them to the water in a little parade. She stays close to the ducklings and protects them until their flight feathers grow in. By the time the young ducks make their first long flight to their wintering grounds, they are completely on their own.

The parents and other adults lose their flight feathers as their breeding season ends. For a few weeks afterward they are unable to fly. At this time drakes usually grow a duller coat of feathers, which they keep for a few months before the more colorful feathers grow back in at breeding time. Ducks kept by people have lived 20 years, but the average life span in the wild is much shorter.

Ducks and people
Ducks have been domesticated—kept and bred by humans—for thousands of years. Many people value ducks for the meat, eggs, and down they provide. The down is used to make warm clothing and bedding.

The duck is a popular game animal. Largely because of hunting, the Labrador duck became extinct in the late 1800s, and other ducks are now rare. Governments in some countries now keep track of wild ducks and control hunting. People who want to hunt waterfowl in the United States are required to buy a special stamp. Some of the money the government gets from selling the stamp is used to maintain breeding habitats.