The carnivores (order Carnivora) are the chief flesh-eating mammals, although hunting as a way of life is shared by others, such as seals and some whales. But the name Carnivora is misleading because at least two species the red, or lesser, panda and the giant panda eat mostly leaves, and some bears eat very little meat. Also, many of the smaller carnivore species are actually omnivorous or insectivorous. The order, which contains seven families and more than 100 genera, is distributed throughout the world, except for Antarctica and some islands.
Most carnivores live on the ground or in trees, but there are also aquatic species, such as the sea otter. Although social patterns vary widely among species, most are fiercely territorial. The two most prominent groups, the cats and their relations and the dogs and related species, have developed different hunting techniques. Dogs tend to run down their prey and many are social and hunt in packs. With the notable exception of African lions, cats tend to be solitary ambushers.
The long, flexible body of the hunting animals and their way of life are adapted to their predatory existence. Terrestrial carnivores are surefooted and agile, and can run swiftly. Most species naturally stand on the tips of their toes with four or five toes touching the ground, and many have claws. The claws help grip the ground and grasp prey. They are also useful for digging and scratching. Some species, such as dogs, cats, and hyenas, have a dewclaw on each forefoot, which represents a toe that no longer touches the ground.
One of the distinguishing features of carnivores is their long, pointed, canine teeth, which they use for stabbing and holding prey. The skull of a carnivore is strong, and powerful muscles work the jaws. In some species, there is a ridge of bone on top of the cranium called a sagittal crest, which serves to increase the anchorage for the upper end of the jaw muscles. The lower jaw can only open and shut, with little ability for sideways grinding movements of the teeth.
In proportion to their body size, carnivores have a large, well developed brain that makes possible the intelligent behavior needed for hunting. Their senses are efficient, enabling the animals first to locate prey at a distance and then to guide the attack. Carnivores have forward-facing eyes that help in judging distance accurately when they spring on prey. The eyes of many carnivores have an internal reflector, called the tapetum, which increases the eyes’ sensitivity at night. A structure called the lucidum causes carnivores’ eyes to shine when a light is directed at them.
Carnivores have a fine sense of smell, important both for trailing prey and for communication. Scent released from the anal and other glands conveys information about an animal’s identity, sex, and territorial ownership.
Most carnivores breed only once a year although a few species, such as some weasels, reproduce twice a year. Litters vary in size from the single offspring of bears to the 12 or more of skunks. The young are usually blind at birth and are necessarily dependent on parental care for some time. In captivity, some carnivores have been known to live for more than 30 years.
The dogs (family Canidae) are generalized hunters. The family includes wolves, coyotes, jackals, foxes, and the Cape hunting dog. They are the most vocal of the carnivores, capable of a variety of barks, howls, and whines. Those members of the family that hunt in packs can bring down large animals, but the solitary hunters usually live on small rodents, insects, or birds.
The wolf looks like a heavily built German shepherd dog. Until persecution by humans drove it from much of its former range, it could be found over most of the Northern Hemisphere. The basic unit of wolf society is a female with her offspring. When the cubs mature, they stay with the mother and hunt with her. The male stays with his family and helps feed the cubs. Lone wolves eat anything they can obtain, but most wolves form packs of 8 to 20 animals, which are highly efficient hunting groups capable of bringing down prey as large as an elk.
The coyote resembles a small wolf. It is found throughout North America and lives in pairs or family groups that feed on anything from deer to trash from humans.
Several species of jackals live throughout Africa and southern Asia, jackals usually live in pairs that cooperate in hunting, and young from a previous litter may also help to feed pups. Jackals sometimes gather in packs to prey on large animals or to scavenge.
The red fox has as extensive a range as the wolf, and has been introduced into Australia as a quarry for hunters. Unlike the wolf, the fox has survived continuous persecution and has even taken to living on the fringes of towns and cities, where it scavenges on people’s garbage. Some foxes are wanderers without a permanent home, but most live in pairs in territories, although they hunt separately.
The Arctic fox has two forms of seasonal color change. It has either white fur in winter, which turns brown in summer, or a blue-gray winter coat that becomes darker in summer. This variation seems to reflect the harshness of the climate and the environment
The hot, dry parts of Africa are the home of the bat-eared fox and the fennec. Both species have large ears that act as radiators to help keep the animal cool and as sound receivers to increase the sensitivity of hearing.
The Cape hunting dog of the African savanna is exceptionally social. It lives in packs of up to 20 that cooperate to hunt zebras and antelopes. The members of the pack share the food and, when a female has pups, the other dogs bring food back to the den.
The bears (family Ursidae) are the largest members of the carnivore order and are found in the Northern Hemisphere and in parts of South America. Zoologists generally recognize seven species of bears—big brown bears, American black bears, Asiatic black bears, polar bears, sun bears, sloth bears, and spectacled bears. For many years, zoologists hotly debated whether the giant panda should be classified in the bear family or the raccoon family. However, recent comparisons of panda DNA to that of other bears confirms that pandas are more closely related to bears than to raccoons.
Bears are heavy-bodied, and most species live in forests. They are usually omnivorous and have blunt teeth. They eat a variety of plant foods, such as fruit, grass, nuts, and acorns, but eagerly feed on fish and other small animals when they are available. They are especially fond of ants, termites, and grubs. Bears are solitary animals, although several may gather around a good source of food such as a garbage dump or a shallow salmon run.
Bear species that live in cold places spend most of the winter in a state similar to sleeping. Zoologists disagree about whether this winter sleep is actually hibernation. Some point out that a bear’s body temperature, unlike that of other hibernating animals, does not drop significantly during winter sleep. In addition, a bear wakes up easily, and may become fairly active on mild winter days. As a result, many zoologists prefer to refer to a bear’s sleep period as winter lethargy or incomplete hibernation.
Most bear cubs are born during the winter sleep period of the mother bear. Twins are most common, but the number of young born may vary from one to four. The cubs are extremely small at birth, weighing less than 1/350 of their mother’s weight.
Kinds of bears
The big brown bear weighs more than 1,500 pounds (680 kilograms). It lives in the northern forested areas of North America, Europe, and Asia. The grizzly bear is a large subspecies of the brown bear, but is less common. Another North American bear is the black bear, which is smaller than the brown bear. It is an agile climber even when adult. The spectacled bear is the only true bear in the Southern Hemisphere. The Asiatic black bear is also called a moon bear because of a white, crescentshaped mark on its chest. The sloth bear of India and Sri Lanka has a long snout with mobile lips that it uses to suck termites from their nests. The female carries her young on her back when they first leave the den. The small est bear is the sun bear, also called a Malayan bear, of Burma, Malaysia, and Borneo. It is an excellent climber and has a short coat that is less shaggy than that of other bears.
The polar bear differs from other bears in that its diet consists almost exclusively of meat. This bear lives in the Arctic, where other types of food are unavailable. The polar bear spends most of its time on pack ice, where it preys mainly on seals. It is a strong swimmer but never hunts in water. The bear either pulls seals and fish out of the water or catches seals on the ice. Polar bears also occasionally eat birds, hares, and berries. The thick white fur of the polar bear covers even the soles of its feet, giving added grip on the ice as well as insulation from the cold.
Giant pandas live in the remote bamboo and rhododendron forests of southwestern China and eastern Tibet, where they feed almost exclusively on bamboo shoots. They have a woolly white coat with black legs and shoulders, black ears, and black patches around the eyes. Adults measure up to 5 feet (1.5 meters) long and weigh 150 to 350 pounds (70 to 160 kilograms). A unique feature of pandas is a sesamoid bone that rises from the wrist and acts as a sixth finger on the forepaw, used to hold the shoots. Pandas have broad teeth for chewing tough shoots into a pulp, and a muscular stomach for aiding digestion.
The raccoon family
The raccoon family (Procyonidae) includes the raccoons, cacomistles, kinkajous, ringtails, anc red, or lesser, pandas. Most are small animals that spend much of their time in trees. Except for the red panda, all raccoons live in temperate and tropical areas of the Americas and eastern Asia. Some procyonids have long, ringed tails. That of the tree-dwelling kinkainu is prehensile. The diet of raccoons includes a variety of small animals, although the kinkajou and olingo eat mainly fruit. Most procyonids are nocturnal, except for coatis, which usually move about during the day. Most raccoons also live in pairs or groups. The coatis are the most social of this group, living in large bands.
The raccoon is found throughout North America and in parts of Central America. Like the fox, it has adapted to living in populated areas and scavenges in trash cans, but in wilder regions it frequently feeds along the water’s edge on shellfish, crayfish, and frogs.
Like the giant panda, the red panda also lives in bamboo forests, from China to Nepal. It has a similar sixth finger for handling bamboo but frequently also eats acorns, roots, fruit, and small birds.
The weasel family
The family Mustelidae, with 67 species, is the largest and most varied of the carnivores. Most mustelids have long, slender bodies and short legs and are hunters of earthworms, frogs, lizards, snakes, and warm-blooded prey. From this basic pattern they have developed a variety of life styles. The martens are treeclimbers, the minks and otters are aquatic, and the badgers are stocky digging animals. Weasels’ diets also vary among species. For example, the tayra of Central America and South America eats fruit, small animals, and birds. The larger wolverine, or glutton, is a powerful scavenger of the high northern latitudes that also can kill deer and cattle weakened by harsh weather.
Weasels are lithe, fast-moving animals and are small enough to follow mice and voles down their burrows. In the northern parts of the weasel range North America, Europe, Asia, and Indonesia stoats and weasels grow a white coat in winter, which makes them inconspicuous in snow. Minks and polecats are larger members of the family. And the American least weasel is the smallest flesh-eating animal in the world.
The black-footed ferret is one of the rarest carnivores. It lives on the North American prairies and preys almost exclusively on prairie dogs. It was virtually extinct in the wild because farmers and ranchers had exterminated prairie dogs in many areas. However, black-footed ferrets are making a comeback, thanks to reintroduction of zoo-born animals into the wild.
Most carnivores have anal glands that secrete a fluid used for marking territory. But the best-known example is the skunk, also a mustelid, which uses the fluid for defense. The glands also have been modified for the same purpose in the Asian stink badger, the African striped weasel, and the African zorilia.
The badger of Europe and Asia is one of the few social mustelids and one of the largest It lives in family groups called clans. The clan territory centers on the animals burrows, or setts, which may form an extensive underground network. Badgers are nocturnal and feed mainly on earthworms and insects. The American badger, however, is more solitary and its diet is mainly rodents. The honey badger, or ratel, is known for its association with the honey guide, a bird that leads honey-eating mammals to beehives. The ratel opens the nest to devour the contents, and the honey guide feeds on the scraps.
Some of the largest mustelids are the otters. Eighteen species live in fresh water, but some river otters and the sea otter frequent the sea and shoreline. Otters swim with powerful undulations of their bodies and broad tails and steer with their webbed feet. They can dive for several minutes in search of fish and other aquatic animals, closing their ears and nostrils while submerged. The sea otter, which lives off the west coast of North America, feeds on crabs, sea urchins, and shellfish. It smashes them open by banging them on a stone, which it carries on its chest while floating on its back. It also carries and nurses its young in this position. Unlike most marine animals, sea otters do not have a heavy insulating layer of fat. Instead, they rely on the protection of a layer of air trapped by their long, soft fur.
The mongoose family
The mongooses and civets (family Viverridae) resemble weasels and, indeed, occupy similar ecological niches in Old World tropical regions. Many have spotted coats and ringed tails. Some, such as the genets, are agile, catlike tree climbers, whereas the otter civet and crab-eating mongoose hunt in water.
Viverrids prey mostly on small animals, though some also eat fruit. Mongooses are known to attack snakes, using their speed and agility to confuse the snake and avoid its counterattacks. They have been introduced to several parts of the world to destroy poisonous snakes and rats, but cause destruction among native wildlife and also raid poultry pens, mainly for eggs. Most viverrids are solitary and active by night, because although they are good fighters, they are small enough to be attacked by such birds of prey as eagles, which hunt by day. Some species of viverrids that are active during the day live in troops and cooperate to watch for danger and drive away large predators.
Hyenas (family Hyaenidae) have had a bad reputation as cowardly scavengers, but are now known to be fierce predators as well as eaters of carrion. The three species that live in Africa and southwestern Asia are strong runners and hunt in packs, chasing herds of antelopes or zebras until a victim can be caught and pulled down. Their powerful jaws and large, sharp teeth can crunch even the largest bones. Hyenas have a big head and well developed forelegs. They have a characteristic trot, but are also able to run at high speeds. Spotted hyenas are as noisy as many dog species, making howling and “laughing” sounds.
The African aardwolf is a type of hyena, but it has weak jaws, small teeth, and lives mostly on termites and other insects.
The family Felidae consists of six genera and 36 species. The main genus, Felis, with 25 species, includes the mountain lion, or puma; the ocelot; the serval; and many species of smaller wild cats in addition to the domestic cat. The other main genera are Lynx, with four species, including the Caracas and the bobcat, and Panthera, which also has four species—the jaguar, the leopard, the tiger, and the lion.
Compared with other carnivores, the cats have a short muzzle and a broad, rounded head. With the exception of the lion, the fur is soft and often marked with spots or stripes. Cats are specialized hunters with lithe, compact bodies and large, sharp, scissorlike cheek teeth, called carnassials. The whiskers are long and sensitive, and cats have acute sight, hearing, and sense of smell. Cats vary widely in size and appearance. The smallest wild cats are about the same size as the domestic cat, whereas the largest species, the tiger, has a body length of more than 9 feet (2.8 meters), or 10.5 feet (3.2 meters) including the tail.
Most cats are nocturnal, and all but the lion hunt alone. Lions live in prides of several females and their cubs, with one or more males. Several members of the pride usually hunt together. They lie in ambush or sneak forward slowly toward their prey until they are close enough to leap up and catch it, bringing it down with their claws and a bite that breaks the victim’s neck. Unlike most carnivores, all cats except the cheetah have retractile claws. They extend these claws to help grasp and slash prey, and withdraw them into sheaths when they are not in use. The cheetah’s blunt, nonretractile claws give it a good grip on the ground as it sprints at speeds up to about 70 miles (110 kilometers) per hour. Its light build and flexibility help it to turn fast, and its long tail provides steering and balance.
The big cats the lion, tiger, leopard, and jaguar are also characterized by their roar, which is heard at night. The roar is made possible by an additional ligament in the throat that is attached to the hyoid bone.