Spotted Hyena (Crocuta)

While hyenas are known as scavengers, they also possess great intelligence and skill on the hunt. One strategy is for a single hyena to cause confusion in the herd, while the others in the pack pick off an older or weaker member and chase the rest away.

Spotted hyenas are famed scavengers and often dine on the leftovers of other predators. But these hardy beasts are also skilled hunters that will take down wildebeest or antelope. They also kill and eat birds, lizards, snakes, and insects.

In an increasingly overpopulated Africa, hyenas and humans come into frequent contact. In fact, the Maasai people of Kenya and Tanzania actually leave their dead to be consumed by hyenas. However, these intelligent and bold animals will raid food stores and crops and are blamed for many livestock and even some human deaths. In some areas they have been heavily hunted as destructive pests.

Spotted hyenas are the largest of three hyena species. Brown and striped hyenas are the other two. Although hyenas appear similar to dogs, they are actually more closely related to cats. They live throughout much of Africa and eastwards through Arabia to India. Spotted hyenas live together in large groups called clans that may include up 80 individuals and are led by females.

Squirrel (Sciuridae)

Tree squirrels, like this eastern gray squirrel, are seen in many parks, backyards, and forests throughout the world.

Squirrels are familiar to almost everyone. More than 200 squirrel species live all over the world, with the notable exception of Australia.

The tiniest squirrel is the aptly named African pygmy squirrel—only five inches (thirteen centimeters) long from nose to tail. Others reach sizes shocking to those who are only familiar with common tree squirrels. The Indian giant squirrel is three feet (almost a meter) long.

Like other rodents, squirrels have four front teeth that never stop growing so they don't wear down from the constant gnawing. Tree squirrels are the types most commonly recognized, often seen gracefully scampering and leaping from branch to branch. Other species are ground squirrels that live in burrow or tunnel systems, where some hibernate during the winter season.

Steller Sea Lion (Eumetopias jubatus)

"These animals are always yelling at each other," writes photographer Joel Sartore of the Steller sea lions on Alaska's Lowrie Island. Here, two females go nose-to-nose over a disputed bit of territory in a crowded rookery. Alaska's Steller sea lion populations have been in precipitous decline over the last 30 years, and scientists are at a loss to explain the cause.

Stellers are the largest of all sea lions and they have an appetite to match. These giant pinnipeds hunt fish, squid, octopus and, rarely, smaller seals. They are found off northern Pacific coasts from Japan to California.

Steller sea lion breeding is one of nature's great mass spectacles. When these giants thunder ashore, their favored beaches, called rookeries, disappear under their numbers. Young pups are sometimes crushed by the throng, unheeded by powerful males with only a single purpose in mind. Bulls (males) must establish and hold a beach territory in order to breed. Most do not achieve this until they are nine or ten years of age.

Sumatran Rhinoceros (Dicerorhinus sumatrensis)

Unlike its Indian and African cousins, the critically endangered Sumatran rhinoceros is covered with patches of stiff hair, most prominent on its ears.

The two-horned Sumatran rhinoceros shares the bleak distinction of world’s most endangered rhino with its regional cousin, the Javan rhino. The smallest of the rhino family, the Sumatran rhinoceros lives in isolated pockets in the dense mountain forests of Malaysia, Indonesia, and possibly Myanmar (Burma).

Sumatran rhinos are generally solitary creatures that feed on fruit, twigs, leaves, and shrubs. Like other rhinos they have a keen sense of smell and sharp hearing, and they leave a network of scented trails throughout the forest in order to find one another.

As the smallest rhino, they weigh about 1,760 pounds (800 kilograms), and grow to a height near 5 feet (1.5 meters) at the shoulders and 8 to 10 feet (2.5 to 3.2 meters) in length. Unlike most other rhinos, their hide, dark red-brown in color, is covered with patches of short, dark, stiff hair. The hair helps keep mud caked to the body, which cools the hide and protects it from insects.

Sun Bear (Helarctos malayanus)

Sun bears are so named because of the bib-shaped patch on their chests, which legend says represents the rising sun.

The reclusive sun bear, smallest member of the bear family, lives an insular life in the dense lowland forests of Southeast Asia.
Found from southern China to eastern India and as far south as Indonesia, sun bears, also called Malayan sun bears, take their name from the bib-shaped golden or white patch on their chest, which legend says represents the rising sun. They have a stocky, muscular build, small ears, and a short muzzle, which has earned them the nickname “dog bear.” Their sleek, black coat is short to avoid overheating in the tropical weather but thick and coarse to provide protection from twigs, branches, and rain.
Sun bears grow to only about half the size of an American black bear. Males, slightly larger than females, are about 5 feet (1.5 meters) in length and weigh up to 150 pounds (70 kilograms), a stature which suits their arboreal lifestyle and allows them to move easily through the trees. They have even been observed making sleeping platforms high above the ground out of branches and leaves.

Tapir (Tapiridae)

The prehensile trunk of the tapir has changed little in millions of years of evolution.

Tapirs look something like pigs with trunks, but they are actually related to horses and rhinoceroses. This eclectic lineage is an ancient one—and so is the tapir itself. Scientists believe that these animals have changed little over tens of millions of years.

Tapirs have a short prehensile (gripping) trunk, which is really an extended nose and upper lip. They use this trunk to grab branches and clean them of leaves or to help pluck tasty fruit. Tapirs feed each morning and evening. During these hours they follow tunnel-like paths, worn through the heavy brush by many a tapir footstep, to reach water holes and lush feeding grounds. As they roam and defecate they deposit the seeds they have consumed and promote future plant growth.

Though they appear densely built, tapirs are at home in the water and often submerge to cool off. They are excellent swimmers and can even dive to feed on aquatic plants. They also wallow in mud, perhaps to remove pesky ticks from their thick hides.

Tasmanian Devil (Sarcophilus harrisii)

This yawning Tasmanian devil was photographed at a quarantine facility in Hobart, Tasmania, Australia. The site monitors devils for signs of devil facial tumor disease (DFTC), a fatal, contagious cancer that over the past decade has decimated wild populations of the iconic Australian marsupial.

As comical as it is, the familiar Looney Tunes portrayal of a Tasmanian devil as a seething, snarling, insatiable lunatic is, at times, not all that far from the truth.

Tasmanian devils have a notoriously cantankerous disposition and will fly into a maniacal rage when threatened by a predator, fighting for a mate, or defending a meal. Early European settlers dubbed it a "devil" after witnessing such displays, which include teeth-baring, lunging, and an array of spine-chilling guttural growls.

These famously feisty mammals have a coat of coarse brown or black fur and a stocky profile that gives them the appearance of a baby bear. Most have a white stripe or patch on their chest and light spots on their sides or rear end. They have long front legs and shorter rear legs, giving them a lumbering, piglike gait.

Thomson's Gazelle (Gazella thomsonii)

In addition to running at high speeds, Thomson's gazelles also use a bounding leap, called "stotting" or "pronking," to avoid predators.

Gazelles are medium-sized antelopes found in Africa and in Asia as far east as Mongolia. There are some 19 different species of gazelles.

These grazing antelopes live in herds, which can consist of as few as ten or as many as several hundred animals. During the plentiful rainy season, thousands of animals can be seen gathering in large groups.

Gazelles typically frequent wide-open spaces and plains, where they browse on grasses, shoots, and leaves.

Open plains make them visible to predators like cheetahs or wild dogs, but gazelles are fleet of foot. The Thomson's gazelle can reach speeds of 40 miles (64 kilometers) an hour.

Some gazelle species eschew the grasslands for mountainous landscapes or even deserts. During the dry season some grassland gazelles will even take to the African bush in search of water.

Three-Toed Sloth (Bradypus variegatus)

The three-toed sloth's long claws are well suited to an arboreal life but hamper its mobility on the ground, leaving it vulnerable to predators.

The sloth is the world's slowest mammal, so sedentary that algae grows on its furry coat. The plant gives it a greenish tint that is useful camouflage in the trees of its Central and South American rain forest home.

Sloths are identified by the number of long, prominent claws that they have on each front foot. There are both two-toed and three-toed sloths.

All sloths are built for life in the treetops. They spend nearly all of their time aloft, hanging from branches with a powerful grip aided by their long claws. (Dead sloths have been known to retain their grip and remain suspended from a branch.) Sloths even sleep in trees, and they sleep a lot—some 15 to 20 hours every day. Even when awake they often remain motionless. At night they eat leaves, shoots, and fruit from the trees and get almost all of their water from juicy plants.

Two-Toed Sloth (Choloepus hoffmanni)

Sloths spend their lives hanging from trees—eating, mating, and even giving birth.

The sloth is the world's slowest mammal, so sedentary that algae grows on its furry coat. The plant gives it a greenish tint that is useful camouflage in the trees of its Central and South American rain forest home.

Sloths are identified by the number of long, prominent claws that they have on each front foot. There are both two-toed and three-toed sloths.

All sloths are built for life in the treetops. They spend nearly all of their time aloft, hanging from branches with a powerful grip aided by their long claws. (Dead sloths have been known to retain their grip and remain suspended in the air.) Sloths even sleep in trees, and they sleep a lot—some 15 to 20 hours every day. Even when awake they often remain motionless, and two-toed sloths are generally silent. At night they eat leaves, shoots, and fruit from the trees and get almost all of their water from juicy plants.

Wallaby Macropus (Notamacropus)

Wallabies, like their close kangaroo relatives, have long tails for balance and large feet and strong legs for jumping great distances.

Wallabies are members of the kangaroo clan found primarily in Australia and on nearby islands. There are many wallaby species, grouped roughly by habitat: shrub wallabies, brush wallabies, and rock wallabies. Hare wallabies are named for their size and their hare-like behavior.

All wallabies are marsupials or pouched mammals. Wallaby young are born tiny, helpless, and undeveloped. They immediately crawl into their mothers' pouches where they continue to develop after birth—usually for a couple of months. Young wallabies, like their larger kangaroo cousins, are called joeys. Even after a joey leaves the pouch, it often returns to jump in when danger approaches.

Walrus (Odobenus rosmarus)

Both male and female walruses have tusks and have been observed using these overgrown teeth to help pull themselves out of the water.

The mustached and long-tusked walrus is most often found near the Arctic Circle, lying on the ice with hundreds of companions. These marine mammals are extremely sociable, prone to loudly bellowing and snorting at one another, but are aggressive during mating season. With wrinkled brown and pink hides, walruses are distinguished by their long white tusks, grizzly whiskers, flat flipper, and bodies full of blubber.

Walruses use their iconic long tusks for a variety of reasons, each of which makes their lives in the Arctic a bit easier. They use them to haul their enormous bodies out of frigid waters, thus their "tooth-walking" label,

Warthog (Phacochoerus africanus)

Although warthogs look fierce, they are actually herbivores who prefer to flee rather than fight.

Warthogs are members of the same family as domestic pigs, but present a much different appearance. These sturdy hogs are not among the world's most aesthetically pleasing animals—their large, flat heads are covered with "warts," which are actually protective bumps. Warthogs also sport four sharp tusks. They are mostly bald, but they do have some sparse hair and a thicker mane on their backs.

Though warthogs appear ferocious, they are basically grazers. They eat grasses and plants, and also use their snouts to dig or "root" for roots or bulbs. When startled or threatened, warthogs can be surprisingly fast, running at speeds of up to 30 miles (48 kilometers) an hour.

Warthogs are adaptable and are able to go long periods without water, as much as several months in the dry season.

When water is available, warthogs will seek it and often submerge to cool down. They will also wallow in mud for the same purpose—and to gain relief from insects. Birds also aid these hogs in their battle with insects; oxpeckers and other species sometimes ride along on their warthog hosts, feeding on the tiny creatures invading their hides.

Water Buffalo (Bubalus bubalis)

Both male and female water buffalo wear the species’ signature backward-curving horns, although the females’ horns are significantly smaller.

The water buffalo, or Asian buffalo, as it is often called, is the largest member of the Bovini tribe, which includes yak, bison, African buffalo, various species of wild cattle, and others.

Standing 5 to 6.2 feet (1.5 to 1.9 meters) tall at the shoulder, wild water buffalo are formidable mammals with sparse gray-black coats. Males carry enormous backward-curving, crescent-shaped horns stretching close to 5 feet (1.5 meters) long with deep ridges on their surface. Females are smaller in size and weight, but they also have horns, although they are proportionately smaller.

Water buffalo spend much of their day submerged in the muddy waters of Asia’s tropical and subtropical forests. Their wide-splayed hoofed feet prevent them from sinking too deeply in the mud and allow them to move about in wetlands and swamps. These marshes provide good cover and rich aquatic plants to forage on, although water buffalo actually prefer to feed in grasslands on grass and herbs.

Weddell Seal (Leptonychotes weddelli)

Weddell seals are known for their docile nature and are easily approached by humans.

Weddell seals spend much of their time below the Antarctic ice. They have the southernmost range of any seal, but find the chilly waters rich with the prey they seek. These seals do not migrate often and are commonly found within a few miles of their birthplace.

By swimming under the ice, these seals can often avoid their main predators—orcas and leopard seals. The environment helps their own fishing as well. When feeding below the ice, they may dive beneath their prey. As the seal rises, the fish above it are backlit by the ice above and easily spotted in silhouette. Weddell seals can also use air to collect a meal. They have been known to blow air into cracks in the ice. The surprise tactic puts small fish to flight, which the seal then devours. Cod and silverfish are favorites, though these seals also eat small crustaceans, octopuses, and other marine creatures.

Western Lowland Gorilla

Gorillas are very intelligent and have been taught simple sign language in captivity. Like chimpanzees, gorillas have been observed using tools in the wild.

Western lowland gorillas are endangered, but they remain far more common than their relatives, the mountain gorillas. They live in heavy rain forests, and it is difficult for scientists to accurately estimate how many survive in Cameroon, Central African Republic, Congo, Equatorial Guinea, Gabon, Angola, and the Democratic Republic of Congo.

Western lowland gorillas tend to be a bit smaller than their mountain cousins. They also have shorter hair and longer arms.

Gorillas can climb trees, but are usually found on the ground in communities of up to 30 individuals. These troops are organized according to fascinating social structures. Troops are led by one dominant, older adult male, often called a silverback because of the swath of silver hair that adorns his otherwise dark fur. Troops also include several other young males, some females, and their offspring.

The leader organizes troop activities like eating, nesting in leaves, and moving about the group's three-quarter- to 16-square-mile (2- to 40-square-kilometer) home range.

White Rhinoceros (Ceratotherium simum)

White rhinos graze on grasses, walking with their enormous heads and squared lips lowered to the ground. Both black and white rhinoceroses are actually gray. They are different not in color but in lip shape. The black rhino has a pointed upper lip, while its white relative has a squared lip. The difference in lip shape is related to the animals' diets. Black rhinos are browsers that get most of their sustenance from eating trees and bushes. They use their lips to pluck leaves and fruit from the branches. White rhinos graze on grasses, walking with their enormous heads and squared lips lowered to the ground.

White rhinos live on Africa's grassy plains, where they sometimes gather in groups of as many as a dozen individuals. Females reproduce only every two and a half to five years. Their single calf does not live on its own until it is about three years old.

White-Eared Kob (Kobus kob)

The Sudd wetlands of southern Sudan are home to more than 800,000 white-eared kob, best known for their annual migration.

These graceful antelopes of central Africa’s well-watered savannas and floodplain grasslands are best known for their annual migration, which produces one of the natural world’s great spectacles.

The Sudd wetlands of southern Sudan, nourished by the White Nile, are home to an astounding number of white-eared kob—more than 800,000 animals. When joined by tiang antelopes and Mongalla gazelles they form enormous migrating herds of more than 1.2 million individuals. Thickly packed columns of these animals in motion can stretch a staggering 50 miles (80 kilometers) long and 30 miles (48 kilometers) across. Such herds rival the Serengeti’s teeming masses of wildebeests for the title of the world’s most massive—and awe-inspiring—mammal migration.

White-Tailed Deer (Odocoileus virginianus)

White-tailed deer spend their summers grazing in the meadows and move into the forests during winter for protection from the elements.

White-tailed deer, the smallest members of the North American deer family, are found from southern Canada to South America. In the heat of summer they typically inhabit fields and meadows using clumps of broad-leaved and coniferous forests for shade. During the winter they generally keep to forests, preferring coniferous stands that provide shelter from the harsh elements.

Adult white-tails have reddish-brown coats in summer which fade to a duller grayish-brown in winter. Male deer, called bucks, are easily recognizable in the summer and fall by their prominent set of antlers, which are grown annually and fall off in the winter. Only the bucks grow antlers, which bear a number of tines, or sharp points. During the mating season, also called the rut, bucks fight over territory by using their antlers in sparring matches.

Wildebeest Connochaetes taurinus

A wildebeest mother and calf graze on the grassy plains of Namibia. Calves can walk shortly after birth, and keep up with the herd within a week.

The ungainly gnu earned the Afrikaans name wildebeest, or "wild beast," for the menacing appearance presented by its large head, shaggy mane, pointed beard, and sharp, curved horns. In fact, the wildebeest is better described as a reliable source of food for the truly menacing predators of the African savanna: lions, cheetahs, wild dogs, and hyenas.
The gnu (pronounced "g-new" or simply "new") is a member of the antelope family, although its heavy build and disproportionately large forequarters make it look more bovine. Gnus can reach 8 feet (2.4 meters) in length, stand 4.5 feet (1.4 meters) tall at the shoulders and weigh up to 600 pounds (272 kilograms). Both males and females grow horns.

Wolf (Canis lupus)

Gray wolves once populated large portions of North America, Europe, and Asia, but were hunted to near extinction. Their numbers have rebounded due to conservation and reintroduction efforts.

Wolves are legendary because of their spine-tingling howl, which they use to communicate. A lone wolf howls to attract the attention of his pack, while communal howls may send territorial messages from one pack to another. Some howls are confrontational. Much like barking domestic dogs, wolves may simply begin howling because a nearby wolf has already begun.
Wolves are the largest members of the dog family. Adaptable gray wolves are by far the most common and were once found all over the Northern Hemisphere. But wolves and humans have a long adversarial history. Though they almost never attack humans, wolves are considered one of the animal world's most fearsome natural villains. They do attack domestic animals, and countless wolves have been shot, trapped, and poisoned because of this tendency.

Wolverine (Gulo gulo)

The largest member of the weasel family, wolverines are fierce hunters, feeding on small rodents and even weakened caribou.

The wolverine is a powerful animal that resembles a small bear but is actually the largest member of the weasel family.

These tough animals are solitary, and they need a lot of room to roam. Individual wolverines may travel 15 miles (24 kilometers) in a day in search of food. Because of these habitat requirements, wolverines frequent remote boreal forests, taiga, and tundra in the northern latitudes of Europe, Asia, and North America.

Wolverines eat a bit of vegetarian fare, like plants and berries, in the summer season, but this does not make up a major part of their diet—they are tenacious predators with a taste for meat. Wolverines easily dispatch smaller prey, such as rabbits and rodents, but may even attack animals many times their size, such as caribou, if the prey appears to be weak or injured. These opportunistic eaters also feed on carrion

Zebra (Equus burchellii)

Prey for lions and hyenas, zebras are constantly on the lookout for danger.

No animal has a more distinctive coat than the zebra. Each animal's stripes are as unique as fingerprints—no two are exactly alike—although each of the three species has its own general pattern.

Why do zebras have stripes at all? Scientists aren't sure, but many theories center on their utility as some form of camouflage. The patterns may make it difficult for predators to identify a single animal from a running herd and distort distance at dawn and dusk. Or they may dissuade insects that recognize only large areas of single-colored fur or act as a kind of natural sunscreen. Because of their uniqueness, stripes may also help zebras recognize one another.

Zebras are social animals that spend time in herds. They graze together, primarily on grass, and even groom one another.

Thescelosaurus Neglectus

Thescelosaurus neglectus ran upright on two legs, using its long tail for balance. It fed on low-lying vegetation.

This "beautiful but neglected lizard" was not recognized as unique until decades after the first fossils were collected.

Thescelosaurus neglectus was an upright runner that moved on two legs and used its long tail for balance. It remained relatively close to the ground and browsed low-lying vegetation.

Thescelosaurus has been at the heart of a prehistoric controversy because some have suggested the animal represents an evolutionary link between crocodilians and birds. A specimen nicknamed "Willo" may be the first dinosaur ever found with a fossilized heart. Some scientists further suggest that the organ is a four-chambered heart more like those of mammals or birds than those of reptiles.

Triceratops Horridus

Triceratops's head was its most imposing feature. It measured 4 to 5 feet (1.2 to 1.5 meters) across and was ornamented with impressive horns and a head plate.

With its rock-hard horns, shieldlike head plate, and massive torso, Triceratops horridus—"three-horned face"—must have been an intimidating presence in the late Cretaceous period. But this giant was an herbivore, preying only on the vegetation of western North America.
Fossil evidence shows that Triceratops was about 30 feet (9 meters) long and 10 feet (3 meters) tall and weighed 4 to 6 tons. Stout limbs supported Triceratops's girth, but it was unlikely the dinosaur could move very quickly.
Like a modern-day rhinoceros, Triceratops probably spent much of its time grazing on plant matter. It used its beaklike mouth and powerful jaws lined with rows of sharp cheek teeth to shred and grind cycads, ferns, and other low-lying vegetation.
Triceratops's head was its most imposing feature. It measured 4 to 5 feet (1.2 to 1.5 meters) across and was ornamented with impressive horns and a head plate. It used its horns—a short one above its mouth and two long ones above its eyes—to charge predators, such as T. rex. They likely were also used in mating rituals.

Troodon Formosus

With a relatively large brain for its small size, Troodon formosus was probably one of the smartest dinosaurs. It may have been as intelligent as modern birds.

Troodon formosus was a small coelurosaurian dinosaur—a member of the same clade (evolutionary group) to which modern birds belong. Fossilized remains have been discovered of nesting parents and egg clutches. These finds shed some light on reproductive strategies that resemble those of both crocodilians and birds.
Scientists believe that Troodon produced a pair of eggs at periodic intervals and then incubated them in earth nests, sometimes sitting on them and warming them with body heat. Such behavior suggests that these dinosaurs could be an important link on the evolutionary chain, bridging the gap between their earlier relatives (crocodilians) and their later relatives (birds).

Tusotheuthis Longa

Tusoteuthis is believed to have had very large eyes and good eyesight to navigate the depths of the Western Interior Seaway, which is believed to have been as deep as 600 feet (180 meters) in some areas.

Tusoteuthis was a giant squid nearly equal in size to those that ply the oceans today—with their tentacles stretched out, the ancient cephalopods may have measured 25 to 35 feet (8 to 11 meters) long. Like the modern giant squid, Tusoteuthis lacked an outer shell and is known only from discoveries of the rigid support structure in its body called a pen or gladius. The pen was akin to a backbone but made of delicate shell-like material called chitin.
The pen supported a fleshy body with large eyes, a sharp beak, and presumably ten arms lined with suckers that made Tusoteuthis a formidable predator in the Late Cretaceous seas. Smaller cephalopods and fish were likely dietary staples, though small marine reptiles that visited the ocean depths may have fallen prey as well.

Tylosaurus Proriger

Tylosaurus may have ruled the Late Cretaceous seas because all other would-be competitors, such as ichthyosaurs, were already extinct. Though they evolved from terrestrial lizards, the paddle-like limbs of giant mosasaurs like Tylosaurus were useless on land.

Tylosaurus was the deadliest hunter of the ancient seas, ready to seize and kill just about any smaller creature that crossed its path with true jaws of death—lined on each side with two rows of pointy, cone-shaped teeth. Tylosaurus used its snout to locate prey, which, once inside the mosasaur's menacing jaws, was swallowed whole. When the sea monster opened wide for the final gulp, two extra rows of teeth on the roof of its mouth allowed crippled captives no escape.
Tylosaurus grew more than 45 feet (14 meters) long, making it the largest of the marine reptiles called mosasaurs. Like all mosasaurs, a long and muscular, vertically flattened tail powered Tylosaurus through the water, allowing it to ambush its prey with rapid bursts of acceleration. Paddle-like limbs helped steer the slim body covered in lizard-like scales through the water.

Tyrannosaurus Rex

One of the largest dinosaurs that ever lived, Tyrannosaurus rex was a fierce carnivore. Scientists believe this powerful predator could eat up to 500 pounds (230 kilograms) of meat in one bite.

Tyrannosaurus rex was one of the largest meat-eating dinosaurs that ever lived. Everything about this ferocious predator, from its thick, heavy skull to its 4-foot-long (1.2-meter-long) jaw, was designed for maximum bone-crushing action.

Fossil evidence shows that Tyrannosaurus was about 40 feet (12 meters) long and about 15 to 20 feet (4.6 to 6 meters) tall. Its strong thighs and long, powerful tail helped it move quickly, and its massive 5-foot-long (1.5-meter-long) skull could bore into prey.

T. rex's serrated, conical teeth were most likely used to pierce and grip flesh, which it then ripped away with its brawny neck muscles. Its two-fingered forearms could probably seize prey, but they were too short to reach its mouth.

Velociraptor Mongoliensis

Despite its birdlike plumage Velociraptor mongoliensis was not a flier. Its short forelimbs made liftoff impossible, though they may be the evolutionary remnants of an ancient ancestor’s flight-giving wings.

Recent research suggests that Velociraptor mongoliensis was a feathered dinosaur. A forelimb fossil discovered in Mongolia showed quill knobs like those found in many modern birds. These telltale features are evidence of where ligaments attached flight feathers to bone and are considered proof that Velociraptor sported a fine feathery coat.
The dinosaur's plumage may have been used for mating or other visual displays, similar to how modern birds use their colorful feathers, or to help regulate body temperature. The feathers might also have helped females protect their eggs.

Xiphactinus Audax

Xiphactinus was a fast, strong swimmer and may have leapt from waters to dislodge parasites from its skin. It is also possible that there were lots of little fish that swarmed around it, nibbling on parasites, much the same as they do today for larger fish

Xiphactinus was one of the largest bony fish of the Late Cretaceous and is considered one of the fiercest creatures in the sea. A powerful tail and winglike pectoral fins shot the 17-foot-long (5-meter-long) monster through the surface waters of the ocean. Unlucky fish and unsuspecting seabirds were snared inside Xiphactinus's upturned jaw, which was lined with giant, fanglike teeth, giving it an expression akin to that of a bulldog.
A 13-foot-long (4-meter-long) Xiphactinus could open its jaw wide enough to swallow six-foot-long (two-meter-long) fish whole, but it itself was occasionally prey to the shark Cretoxyrhina.

Spider Webs

Spider webs are threads of silk. Spiders can make as many as seven different kinds of silk, with all different purposes—from making egg cases, to hiding. They are mainly used to catch prey.Spider webs are threads of silk. Spiders can make as many as seven different kinds of silk, with all different purposes—from making egg cases, to hiding. They are mainly used to catch prey.

King Cobra (Ophiophagus hannah)

King cobras rarely attack humans, but one bite contains enough venom to bring down an elephant.

It seems unfairly menacing that a snake that can literally "stand up" and look a full-grown person in the eye would also be among the most venomous on the planet, but that describes the famous king cobra.

King cobras can reach 18 feet (5.5 meters) in length, making them the longest of all venomous snakes. When confronted, they can raise up to one-third of their bodies straight off the ground and still move forward to attack. They will also flare out their iconic hoods and emit a bone-chilling hiss that sounds almost like a growling dog.

Their venom is not the most potent among venomous snakes, but the amount of neurotoxin they can deliver in a single bite—up to two-tenths of a fluid ounce (seven milliliters)—is enough to kill 20 people, or even an elephant. Fortunately, king cobras are shy and will avoid humans whenever possible, but they are fiercely aggressive when cornered.

Komodo Dragon (Varanus komodoensis)

With its sheer strength and deadly, bacteria-ridden saliva, the Komodo dragon is the top predator in its range.

Komodo dragons have thrived in the harsh climate of Indonesia's Lesser Sunda Islands for millions of years, although amazingly, their existence was unknown to humans until about 100 years ago.

Reaching 10 feet (3 meters) in length and more than 300 pounds (136 kilograms), Komodo dragons are the heaviest lizards on Earth. They have long, flat heads with rounded snouts, scaly skin, bowed legs, and huge, muscular tails.

As the dominant predators on the handful of islands they inhabit, they will eat almost anything, including carrion, deer, pigs, smaller dragons, and even large water buffalo and humans. When hunting, Komodo dragons rely on camouflage and patience, lying in wait for passing prey. When a victim ambles by, the dragon springs, using its powerful legs, sharp claws and serrated, shark-like teeth to eviscerate its prey.

Leatherback Sea Turtle (Dermochelys coriacea)

Leatherbacks are the largest turtles on Earth, growing up to seven feet (two meters) long and exceeding 2,000 pounds (900 kilograms). These reptilian relics are the only remaining representatives of a family of turtles that traces its evolutionary roots back more than 100 million years. Once prevalent in every ocean except the Arctic and Antarctic, the leatherback population is rapidly declining in many parts of the world.

While all other sea turtles have hard, bony shells, the inky-blue carapace of the leatherback is somewhat flexible and almost rubbery to the touch. Ridges along the carapace help give it a more hydrodynamic structure. Leatherbacks can dive to depths of 4,200 feet (1,280 meters)—deeper than any other turtle—and can stay down for up to 85 minutes.

Leatherbacks have the widest global distribution of all reptile species, and possibly of any vertebrate. They can be found in the tropic and temperate waters of the Atlantic, Pacific, and Indian Oceans,

Marine Iguana (Amblyrhynchus cristatus)

Found only on the Galápagos Islands, marine iguanas often wear distinctive white "wigs" of salt expelled from glands near their noses.

The much-maligned marine iguanas of the Galápagos Islands are so famously homely, even Charles Darwin piled on, describing them as "hideous-looking" and "most disgusting, clumsy lizards."

It's true, they're not pretty, with their wide-set eyes, smashed-in faces, spiky dorsal scales, and knotty, salt-encrusted heads. But what these unusual creatures lack in looks they make up for with their amazing and unique ecological adaptations.

Scientists figure that land-dwelling iguanas from South America must have drifted out to sea millions of years ago on logs or other debris, eventually landing on the Galápagos. From that species emerged marine iguanas, which spread to nearly all the islands of the archipelago. Each island hosts marine iguanas of unique size, shape and color.

Meller's Chameleon (Chamaeleo melleri)

Meller's chameleons are also called "giant one-horned chameleons" because of their large size and the small horn protruding from the front of their snouts.

The Meller's chameleon is the largest of the chameleons not native to Madagascar. Their stout bodies can grow to be up to two feet (two-thirds of a meter) long and weigh more than a pound (one-half kilogram).
Meller's distinguish themselves from their universally bizarre-looking cousins with a single small horn protruding from the front of their snouts. This and their size earn them the common name "giant one-horned chameleon."
They are fairly common in the savanna of East Africa, including Malawi, northern Mozambique, and Tanzania. Almost one-half of the world’s chameleons live on the island of Madagascar.
As with all chameleons, Meller's will change colors in response to stress and to communicate with other chameleons. Their normal appearance is deep green with yellow stripes and random black spots. Females are slightly smaller, but are otherwise indistinguishable from males.

Nile Crocodile (Crocodylus niloticus)

The Nile crocodile has a somewhat deserved reputation as a vicious man-eater. The proximity of much of its habitat to people means run-ins are frequent. And its virtually indiscriminate diet means a villager washing clothes by a riverbank might look just as tasty as a migrating wildebeest. Firm numbers are sketchy, but estimates are that up to 200 people may die each year in the jaws of a Nile croc.

Africa's largest crocodilian, these primordial brutes reach a maximum size of about 20 feet (6 meters) and can weigh up to 1,650 pounds (730 kilograms). Average sizes, though, are more in the range of 16 feet (5 meters) and 500 pounds (225 kilograms). They live throughout sub-Saharan Africa, the Nile Basin, and Madagascar in rivers, freshwater marshes, and mangrove swamps.

The diet of the Nile crocodile is mainly fish, but it will attack almost anything unfortunate enough to cross its path, including zebras, small hippos, porcupines, birds, and other crocodiles. It will also scavenge carrion, and can eat up to half its body weight at a feeding.

Olive Ridley Sea Turtle (Lepidochelys olivacea)

Olive ridleys get their name from the coloring of their heart-shaped shell, which starts out gray but becomes olive green once the turtles are adults. They have one to two visible claws on each of their paddle-like flippers.

The olive ridley turtle is named for the generally greenish color of its skin and shell, or carapace. It is closely related to the Kemp’s ridley, with the primary distinction being that olive ridleys are found only in warmer waters, including the southern Atlantic, Pacific and Indian Oceans.

Olive and Kemp’s ridleys are the smallest of the sea turtles, weighing up to 100 pounds (45 kilograms) and reaching only about 2 feet (65 centimeters) in shell length. The olive ridley has a slightly smaller head and smaller shell than the Kemp’s.

These turtles are solitary, preferring the open ocean. They migrate hundreds or even thousands of miles every year, and come together as a group only once a year for the arribada,

Saltwater Crocodile (Crocodylus porosus)

The largest crocodilians on Earth, saltwater crocs, or "salties," are excellent swimmers and have often been spotted far out at sea.

Earth’s largest living crocodilian—and, some say, the animal most likely to eat a human—is the saltwater or estuarine crocodile. Average-size males reach 17 feet (5 meters) and 1,000 pounds (450 kilograms), but specimens 23 feet (7 meters) long and weighing 2,200 pounds (1,000 kilograms) are not uncommon.

Saltwater crocs, or "salties," as Australians affectionately refer to them, have an enormous range, populating the brackish and freshwater regions of eastern India, Southeast Asia, and northern Australia. They are excellent swimmers and have often been spotted far out at sea.

Classic opportunistic predators, they lurk patiently beneath the surface near the water's edge, waiting for potential prey to stop for a sip of water.

Web-Footed Gecko (Palmatogecko rangei)

The ghostly web-footed gecko is nearly translucent with a pale, salmon-colored undertone and light-brown stripes. Their color provides perfect camouflage among the powdery reddish sands of the Namib Desert, their primary habitat.

These geckos have adapted their webbed feet not only to help them stay atop, but to bury beneath the dunes of the Namib Desert. Strictly nocturnal lizards, they spend the day in self-dug burrows and emerge at night to feed.

Their bloodshot-looking eyes are massively oversized to help them detect prey, which includes crickets, grasshoppers, and small spiders. They move surprisingly quickly across the sand, and adhesive pads on their toes make them excellent climbers.

Web-foots are considered medium-size geckos, reaching an average size of about four inches (ten centimeters) in length. Males are slightly smaller than females.

African Aardvarks

Aardvarks live throughout Africa, south of the Sahara. Their name comes from South Africa's Afrikaans language and means "earth pig." A glimpse of the aardvark's body and long snout brings the pig to mind. On closer inspection, the aardvark appears to include other animal features as well. It boasts rabbitlike ears and a kangaroo tail—yet the aardvark is related to none of these animals.

Aardvarks are nocturnal. They spend the hot African afternoon holed up in cool underground burrows dug with their powerful feet and claws that resemble small spades. After sunset, aardvarks put those claws to good use in acquiring their favorite food—termites.

While foraging in grasslands and forests aardvarks, also called "antbears," may travel several miles a night in search of large, earthen termite mounds.

Lobster (Nephropidae)

To many, it may seem that the lobster’s most natural habitat is on a large, oval plate between a cup of drawn butter and a lemon wedge.

In fact, only a few of the hundreds of types of lobster are caught commercially. But those few species are some of the most heavily harvested creatures in the sea, and generate a multi-billion-dollar industry, with more than 200,000 tons (181,436 metric tons) of annual global catch.

The lobsters that most people know from their dinner plates are the American and European clawed lobsters Homarus americanus and Homarus gammarus. These are cold water species that live on either sides of the northern Atlantic Ocean. There are also tropical lobsters that are widely consumed, but these are generally clawless varieties called spiny and slipper lobsters.

Mandarin Duck

The adult male is a striking and unmistakable bird. It has a red bill, large white crescent above the eye and reddish face and "whiskers". The breast is purple with two vertical white bars, and the flanks ruddy, with two orange "sails" at the back. The female is similar to female Wood Duck, with a white eye-ring and stripe running back from the eye, but is paler below, has a small white flank stripe, and a pale tip to its bill.The Mandarin ducklings are almost identical in look to Wood ducklings, and appear very similar to Mallard ducklings. The ducklings can be distinguished from Mallard ducklings because the eye-stripe of Mandarin ducklings (and Wood ducklings) stops at the eye, while in Mallard ducklings it reaches all the way to the bill.
 

Mutations
 
A mandarin duck swimming in Shepreth Wildlife Park
There are various mutations of the Mandarin Duck found in captivity. The most common is the white Mandarin Duck. Although the origin of this mutation is unknown, it is presumed that the constant pairing of related birds and selective breeding led to recessive gene combinations leading to genetic conditions including albinism.

Teetering triggerfish

Some fish, with their delicate features and calm poised attitudes, always appear ready for their close-ups. Others, like this teetering triggerfish, look like you’ve just snapped a Polaroid of them in the middle of wild weekend in Las Vegas.

To be fair, when expedition leader Enric Sala took this photo, the fish was essentially in the middle of a bath, getting the spa treatment from a tiny cleaner fish visible just below its eyes.

Beyond the Funny Face

I saw the same behavior (and perhaps even the same fish) today as I dove with our fish experts Jenn Caselle from Marine Science Institute, UC Santa Barbara, and Alan Friedlander of the US Geological Survey and University of Hawaii as they laid out rope and tape measures and identified and counted every fish that passed by that line.

Parrot Fish

It's hard to decide which of the colorful parrot fish's many unique characteristics is most remarkable.

There’s its diet, which consists primarily of algae extracted from chunks of coral ripped from a reef. The coral is pulverized with grinding teeth in the fishes’ throats in order to get to the algae-filled polyps inside. Much of the sand in the parrot fish's range is actually the ground-up, undigested coral they excrete.

There's its gender, which they can change repeatedly throughout their lives, and their coloration and patterns, which are a classification nightmare, varying greatly, even among the males, females, and juveniles of the same species.

Finally, there are the pajamas. Every night, certain species of parrot fish envelope themselves in a transparent cocoon made of mucous secreted from an organ on their head. Scientists think the cocoon masks their scent, making them harder for nocturnal predators, like moray eels, to find.

Atlantic Jellyfish

Jellyfish have drifted along on ocean currents for millions of years, even before dinosaurs lived on the Earth. They are abundant in cold and warm ocean water, in deep water, and along coastlines. Jellyfish have tiny stinging cells in their tentacles to stun or paralyze their prey before they eat them.

There are many types of jellyfish in the ocean. These jelly-like creatures pulse along on ocean currents. Inside their bell-shaped body is an opening that is its mouth. They eat and discard waste from this opening. As jellyfish squirt water from their mouths they are propelled forward. Tentacles hang down from the smooth bag-like body and sting their prey. 

Jellyfish stings can be painful to humans and sometimes very dangerous. But jellyfish don't purposely attack humans. Most stings occur when people accidentally touch a jellyfish, but if the sting is from a dangerous species, it can be deadly. The Australian box-like sea wasp is the most toxic to humans. 

Loggerhead Sea Turtles

These beautifully colored sea turtles got their name because their oversized head sort of looks like a big log.

Within their heads are powerful jaws, which loggerheads use for crushing prey like conchs, horseshoe crabs, and other animals with hard shells. They also eat softer foods like jellyfish, fish, seaweed, and a brown algae called sargassum.
Loggerheads live in oceans all over the world, except in the coldest seas. There are more loggerheads in the waters of the United States than any other species of sea turtle. Even so, loggerheads are threatened by many things, including predators, pollution, human development in the turtles' nesting areas, and fishing nets.

Jaguars are the largest of South America's big cats

Jaguars are the largest of South America's big cats and the third largest cats in the world. At one time jaguars roamed all the way to the U.S.-Mexico border, but jaguars are now only occasionally sighted in Texas and Arizona. Most jaguars are found in the Amazon River basin.

Jaguars are secretive and are not known to kill humans. These beautiful and powerful beasts were important in ancient Native American cultures and were used as royal symbols. People believed they could protect them against evil. The name jaguar comes from the Native American word yaguar, which means "he who kills with one leap."

Unlike most cats, jaguars like water and are quite good swimmers.

Tigers Fact

Easily recognized by its coat of reddish-orange with dark stripes, the tiger is the largest wild cat in the world. The big cat weighs up to 720 pounds (363 kilograms), stretches 6 feet (2 meters) long, and has a 3-foot- (1-meter-) long tail. The powerful predator generally hunts alone, able to bring down prey such as deer and antelope.

Tigers wait until dark to hunt. Once a tiger has spotted its prey, it sneaks as close as possible to its victim. Then the tiger sprints to the unsuspecting animal, usually pulling it off its feet with its teeth and claws. If the prey animal is large, the tiger bites its throat to kill it; smaller prey is usually killed when the tiger breaks its neck.

Tigers have been known to eat up to 60 pounds (27 kilograms) of meat in one night, but more often they consume about 12 pounds (5 kilograms) during a meal.