National Geographic (Alligator Gar)

The prehistoric relatives of this megafish inhabited many parts of the world, but today gars live only in North and Central America.
Of the seven known gar species, the alligator is the largest, reaching up to ten feet (three meters) long and tipping the scales at up to 300 pounds (140 kilograms). These menacing-looking behemoths are generally olive green or yellow and have a heavily scaled body. A tooth-filled mouth and wide, alligator-like snout give the species its name.
These freshwater giants may look fierce, but attacks against people are unknown. They can pose a passive danger, though—the fish's eggs are poisonous to humans if ingested.
Adult gars have few natural predators, although alligators have been known to attack them. Young are preyed upon by larger fish. Alligator gars prey on fish, but they are opportunistic and have been known to feed on everything from waterfowl and small turtles to carrion.
Alligator gars are found throughout much of the coastal U.S. Southeast. They inhabit waters as far west as Texas and Oklahoma, as far north as the Mississippi River Basin and the lower Ohio and Missouri river systems, and southern drainages well into Mexico.

Gars inhabit lakes, bayous, and bays and are able to tolerate brackish and even salt water. But these toothy giants prefer large, slow-moving rivers, particularly those with wide floodplains, where shallow waters provide hatchlings with some protection from predators.
Unfortunately for the alligator gar, flood-control measures such as dams and dikes have dramatically altered their riverine ecosystems and largely eliminated their preferred spawning habitats across North America. These breeding challenges have contributed to significant population declines across much of the animal's range.
Alligator gars are also targeted by both commercial and sport fisheries and have frequently been overfished. They are now protected by law in parts of their range

National Geographic (Leopard seal)

The leopard seal is named for its black-spotted coat. The pattern is similar to that of the famous big cat, though the seal's coat is gray rather than golden in color. This seal is sometimes called the sea leopard, and the resemblance is more than skin deep. Like their feline namesakes, leopard seals are fierce predators. They are the most formidable hunters of all the seals and the only ones that feed on warm-blooded prey, such as other seals. Leopard seals use their powerful jaws and long teeth to kill smaller seals, fish, and squid.
These effective predators live in frigid Antarctic and sub-Antarctic waters, where they also eat penguins. They often wait underwater near an ice shelf and snare the birds just as they enter the water after jumping off the ice. They may also come up beneath seabirds resting on the water surface and snatch them in their jaws.
Shellfish are a far less dramatic prey but still an important part of the leopard seal's diet.

Leopard seals are earless seals. They have long bodies (10 to 11.5 feet/3 to 3.5 meters) and elongated heads. Like most other seals, leopard seals are insulated from frigid waters by a thick layer of fat known as blubber.
Though the leopard seal is known for its coat, it has not been commercially hunted for its skin like its fur seal relatives.

National Geographic (Zebra)

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.
Plains (Burchell's) zebras are the most common species. They live in small family groups consisting of a male (stallion), several females, and their young. These units may combine with others to form awe-inspiring herds thousands of head strong, but family members will remain close within the herd.
Zebras must be constantly wary of lions and hyenas. A herd has many eyes alert to danger. If an animal is attacked, its family will come to its defense, circling the wounded zebra and attempting to drive off predators.

National Geographic (Komodo dragons)

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.
Animals that escape the jaws of a Komodo will only feel lucky briefly. Dragon saliva teems with over 50 strains of bacteria, and within 24 hours, the stricken creature usually dies of blood poisoning. Dragons calmly follow an escapee for miles as the bacteria takes effect, using their keen sense of smell to hone in on the corpse. A dragon can eat a whopping 80 percent of its body weight in a single feeding.
There is a stable population of about 3,000 to 5,000 Komodo dragons on the islands of Komodo, Gila Motang, Rinca, and Flores. However, a dearth of egg-laying females, poaching, human encroachment, and natural disasters has driven the species to endangered status.

National Geographic (Fossa)

A relative of the mongoose, the fossa is unique to the forests of Madagascar, an African island in the Indian Ocean. Growing up to 6 feet (1.8 meters) long from nose to tail tip, and weighing up to 26 pounds (12 kilograms), the fossa is a slender-bodied catlike creature with little resemblance to its mongoose cousins.
It is the largest carnivore and top predator native to Madagascar and is known to feed on lemurs and most other creatures it can get its claws on, from wild pigs to mice. Unlike mongooses, and more like felines, the fossa has retractable claws and fearsome catlike teeth. Its coat is reddish brown and its muzzle resembles that of a dog.
The fossa is also equipped with a long tail that comes in handy while hunting and maneuvering amongst the tree branches. It can wield its tail like a tightrope walker's pole and moves so swiftly through the trees that scientists have had trouble observing and researching it.

The elusive fossa is a solitary animal and spends its time both in the trees and on the ground. It is active at night and also during the day. Females give birth to an annual litter of two to four young, and adulthood is reached after about three years.
Madagascar is home to an enormous variety of plant and animal life, and a number of species are unique to the island—including over 30 species of lemur, the fossa’s prey of choice. Explorers first arrived on the island some 2,000 years ago, and scientists believe that they would have been met by a bizarre assemblage of now-extinct beasts, including lemurs the size of gorillas and a ten-foot-tall (three-meter-tall) flightless bird.
Presently, fossas are endangered creatures due to habitat loss. Less than ten percent of Madagascar’s original, intact forest cover, the fossa’s only home, remains today.

National Geographic (Alligator Snapping Turtle)

The prehistoric-looking alligator snapping turtle is the largest freshwater turtle in North America and among the largest in the world. With its spiked shell, beaklike jaws, and thick, scaled tail, this species is often referred to as the "dinosaur of the turtle world."
Found almost exclusively in the rivers, canals, and lakes of the southeastern United States, alligator snappers can live to be 50 to 100 years old. Males average 26 inches (66 centimeters) in shell length and weigh about 175 pounds (80 kilograms), although they have been known to exceed 220 pounds (100 kilograms). The much smaller females top out at around 50 pounds (23 kilograms).
Alligator snappers spend most of their lives in water, the exception being when females trudge about 160 feet (50 meters) inland to nest. They can stay submerged for 40 to 50 minutes before surfacing for air.

The alligator snapper employs a unique natural lure in its hunting technique. Its tongue sports a bright-red, worm-shaped piece of flesh that, when displayed by a motionless turtle on a river bottom, draws curious fish or frogs close enough to be snatched.
Adult snappers have no natural predators other than humans, who capture them for their meat and shells, and to sell in the exotic animal trade. A severe reduction in population due to unregulated harvesting and habitat loss has led states to protect them throughout most of their range, and they are listed as a threatened species.

National Geographic( Whale Shark)

As the largest fish in the sea, reaching lengths of 40 feet (12 meters) or more, whale sharks have an enormous menu from which to choose. Fortunately for most sea-dwellers—and us!—their favorite meal is plankton. They scoop these tiny plants and animals up, along with any small fish that happen to be around, with their colossal gaping mouths while swimming close to the water's surface.
The whale shark, like the world's second largest fish, the basking shark, is a filter feeder. In order to feed, it juts out its formidably sized jaws and sucks in everything in the vicinity. It then shuts its mouth, forcing water to filter out of its gills. Everything that remains becomes the giant shark's dinner.
The whale shark's flattened head sports a blunt snout above its mouth with short barbels protruding from its nostrils. Its back and sides are gray to brown with white spots among pale vertical and horizontal stripes, and its belly is white. Its two dorsal fins are set rearward on its body, which ends in a large dual-lobbed caudal fin (or tail).
Preferring warm waters, whale sharks populate all tropical seas. They are known to migrate every spring to the continental shelf of the central west coast of Australia. The coral spawning of the area's Ningaloo Reef provides the whale shark with an abundant supply of plankton.

Although massive, whale sharks are docile fish and sometimes allow swimmers to hitch a ride. They are currently listed as a vulnerable species; however, they continue to be hunted in parts of Asia, such as Taiwan and the Philippines.

National Geographic (Tasmanian Devil)

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.
The Tasmanian devil is the world's largest carnivorous marsupial, reaching 30 inches (76 centimeters) in length and weighing up to 26 pounds (12 kilograms), although its size will vary widely depending on its specific range and the availability of food. Its oversize head houses sharp teeth and strong, muscular jaws that can deliver, pound for pound, one of the most powerful bites of any mammal.
Tasmanian devils are strictly carnivorous, surviving on small prey such as snakes, birds, fish, and insects and frequently feasting communally on carrion. They are at their most rowdy when jockeying for position on a large carcass. Like other marsupials, when they are well fed, their tails swell with stored fat.
Devils are solitary and nocturnal, spending their days alone in hollow logs, caves, or burrows, and emerging at night to feed. They use their long whiskers and excellent sense of smell and sight to avoid predators and locate prey and carrion. They'll eat pretty much anything they can get their teeth on, and when they do find food, they are voracious, consuming everything—including hair, organs, and bones.
Mothers give birth after about three weeks of pregnancy to 20 or 30 very tiny young. These raisin-size babies crawl up the mother's fur and into her pouch. However, the mother has only four nipples, so only a handful of babies survive. Infants emerge after about four months and are generally weaned by the sixth month and on their own by the eighth.
Once abundant throughout Australia Tasmanian devils are now indigenous only to the island state of Tasmania. Their Tasmanian range encompasses the entire island, although they are partial to coastal scrublands and forests. Biologists speculate that their extinction on the mainland is attributable to the introduction of Asian dogs, or dingoes.
Efforts in the late 1800s to eradicate Tasmanian devils, which farmers erroneously believed were killing livestock (although they were known to take poultry), were nearly successful. In 1941, the government made devils a protected species, and their numbers have grown steadily since.
Survival Threatened

Tragically, though, a catastrophic illness discovered in the mid-1990s has killed tens of thousands of Tasmanian devils. Called devil facial tumor disease (DFTD), this rapidly spreading condition is a rare contagious cancer that causes large lumps to form around the animal's mouth and head, making it hard for it to eat. The animal eventually starves to death. Animal health experts are sequestering populations where the disease has not yet appeared and are focusing on captive breeding programs to save the species from extinction. Because of the outbreak, the Australian government has listed Tasmanian devils as vulnerable.

National Geographic (Jaguars)

Jaguars are the largest of South America's big cats. They once roamed from the southern tip of that continent north to the region surrounding the U.S.-Mexico border. Today significant numbers of jaguars are found only in remote regions of South and Central America—particularly in the Amazon basin.
These beautiful and powerful beasts were prominent in ancient Native American cultures. In some traditions the Jaguar God of the Night was the formidable lord of the underworld. The name jaguar is derived from the Native American word yaguar, which means "he who kills with one leap."
Unlike many other cats, jaguars do not avoid water; in fact, they are quite good swimmers. Rivers provide prey in the form of fish, turtles, or caimans—small, alligatorlike animals. Jaguars also eat larger animals such as deer, peccaries, capybaras, and tapirs. They sometimes climb trees to prepare an ambush, killing their prey with one powerful bite.
Most jaguars are tan or orange with distinctive black spots, dubbed "rosettes" because they are shaped like roses. Some jaguars are so dark they appear to be spotless, though their markings can be seen on closer inspection.
Jaguars live alone and define territories of many square miles by marking with their waste or clawing trees.
Females have litters of one to four cubs, which are blind and helpless at birth. The mother stays with them and defends them fiercely from any animal that may approach—even their own father. Young jaguars learn to hunt by living with their mothers for two years or more.

Jaguars are still hunted for their attractive fur. Ranchers also kill them because the cats sometimes prey upon their livestock.