Beluga whale

Belugas are also called white whales, and their unusual color makes them one of the most familiar and easily distinguishable of all the whales. Calves are born gray or even brown and only fade to white as they become sexually mature around five years of age.

White whales are smallish, ranging from 13 to 20 feet (4 to 6.1 meters) in length. They have rounded foreheads and no dorsal fin.

Belugas generally live together in small groups known as pods. They are social animals and very vocal communicators that employ a diversified language of clicks, whistles, and clangs. Belugas can also mimic a variety of other sounds.

These whales are common in the Arctic Ocean's coastal waters, though they are found in subarctic waters as well. Arctic belugas migrate southward in large herds when the sea freezes over. Animals trapped by Arctic ice often die, and they are prey for polar bears, killer whales, and for Arctic people. They are hunted by indigenous people of the north, and by commercial fisheries that brought some populations, such as those in the Gulf of St. Lawrence, to near collapse.

Beluga feed on fish, crustaceans, and worms. The whale is related to the tusked "unicorn" whale known as the narwhal. The beluga is not related to the sturgeon of the same name, which has been heavily fished for its famous caviar.

Blue Whale

Blue whales are the largest animals ever known to have lived on Earth. These magnificent marine mammals rule the oceans at up to 100 feet (30 meters) long and upwards of 200 tons (181 metric tons). Their tongues alone can weigh as much as an elephant. Their hearts, as much as an automobile.

Blue whales reach these mind-boggling dimensions on a diet composed nearly exclusively of tiny shrimplike animals called krill. During certain times of the year, a single adult blue whale consumes about 4 tons (3.6 metric tons) of krill a day.

Blue whales are baleen whales, which means they have fringed plates of fingernail-like material, called baleen, attached to their upper jaws. The giant animals feed by first gulping an enormous mouthful of water, expanding the pleated skin on their throat and belly to take it in. Then the whale's massive tongue forces the water out through the thin, overlapping baleen plates. Thousands of krill are left behind—and then swallowed.

Blue whales look true blue underwater, but on the surface their coloring is more a mottled blue-gray. Their underbellies take on a yellowish hue from the millions of microorganisms that take up residence in their skin. The blue whale has a broad, flat head and a long, tapered body that ends in wide, triangular flukes.

Blue whales live in all the world's oceans occasionally swimming in small groups but usually alone or in pairs. They often spend summers feeding in polar waters and undertake lengthy migrations towards the Equator as winter arrives.

These graceful swimmers cruise the ocean at more than five miles an hour (eight kilometers an hour), but accelerate to more than 20 miles an hour (32 kilometers an hour) when they are agitated. Blue whales are among the loudest animals on the planet. They emit a series of pulses, groans, and moans, and it’s thought that, in good conditions, blue whales can hear each other up to 1,000 miles (1,600 kilometers) away. Scientists think they use these vocalizations not only to communicate, but, along with their excellent hearing, to sonar-navigate the lightless ocean depths.

Really Big Babies

Blue whale calves enter the world already ranking among the planet's largest creatures. After about a year inside its mother's womb, a baby blue whale emerges weighing up to 3 tons (2.7 metric tons) and stretching to 25 feet (8 meters). It gorges on nothing but mother's milk and gains about 200 pounds (91 kilograms) every day for its first year.

Blue whales are among Earth's longest-lived animals. Scientists have discovered that by counting the layers of a deceased whale's waxlike earplugs, they can get a close estimate of the animal's age. The oldest blue whale found using this method was determined to be around 110 years old. Average lifespan is estimated at around 80 to 90 years.

Between 10,000 and 25,000 blue whales are believed to still swim the world's oceans. Aggressive hunting in the 1900s by whalers seeking whale oil drove them to the brink of extinction. Between 1900 and the mid-1960s, some 360,000 blue whales were slaughtered. They finally came under protection with the 1966 International Whaling Commission, but they've managed only a minor recovery since then.

Blue whales have few predators but are known to fall victim to attacks by sharks and killer whales, and many are injured or die each year from impacts with large ships. Blue whales are currently classified as endangered on the World Conservation Union (IUCN) Red List.

Lion

             

                                                                    

The lion (Panthera leo) is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg (550 lb) in weight, it is the second-largest living cat after the tiger. Wild lions currently exist in Sub-Saharan Africa and in Asia with an endangered remnant population in Gir Forest National Park in India, having disappeared from North Africa and Southwest Asia in historic times. Until the late Pleistocene, about 10,000 years ago, the lion was the most widespread large land mammal after humans. They were found in most of Africa, across Eurasia from western Europe to India, and in the Americas from the Yukon to Peru.The lion is a vulnerable species, having seen a possibly irreversible population decline of thirty to fifty percent over the past two decades in its African range. Lion populations are untenable outside designated reserves and national parks. Although the cause of the decline is not fully understood, habitat loss and conflicts with humans are currently the greatest causes of concern.

Lions live for ten to fourteen years in the wild, while in captivity they can live longer than twenty years. In the wild, males seldom live longer than ten years, as injuries sustained from continual fighting with rival males greatly reduce their longevity. They typically inhabit savanna and grassland, although they may take to bush and forest. Lions are unusually social compared to other cats. A pride of lions consists of related females and offspring and a small number of adult males. Groups of female lions typically hunt together, preying mostly on large ungulates. Lions are apex and keystone predators, although they scavenge as opportunity allows. While lions do not typically hunt humans, some have been known to do so.

Golden Lion Tamarin

Lion tamarins take their name from their impressive manes—thick rings of hair reminiscent of Africa's great cats. The golden lion tamarin may be the most beautiful of the four lion tamarin species. Its abundant golden hair frames a charismatic black face and covers its small body and tail. Despite their name, these rare primates have far more in common with their monkey relatives than any feline.

The golden lion tamarin forms social family groups. Males help to raise their offspring, and often carry their young on their backs in between feedings. Tamarin young are usually twins.

Golden lions live primarily in the trees. They sleep in hollows at night and forage by day while traveling from branch to branch. Long fingers help them stay aloft and snare insects, fruit, lizards, and birds.

These interesting animals are critically endangered, as are many of the forests in which they live. Brazil's Atlantic coastal rain forests are disappearing due to ever-expanding logging, agriculture, and industry, and unfortunately, the golden lion tamarin is in danger of vanishing with them.

Gelada

Gelada monkeys live only in the high mountain meadows of Ethiopia—an environment very unlike those of their forest- or savanna-dwelling primate relatives. This high-altitude homeland is replete with steep, rocky cliffs, to which geladas have adapted. At night, the animals drop over precipice edges to sleep huddled together on ledges.

These baboon-size animals are the world's most terrestrial primates—except for humans. As grass-eaters, they are the last surviving species of ancient grazing primates that were once numerous. Geladas spend most of their day sitting down, plucking and munching on grasses. They have fatty rear ends, much like human buttocks, which seem well adapted to this activity.

Theropithecus gelada live in small family units of one male and three to six females. Though males are larger and more colorful, females dominate gelada societies. When an aging male begins to decline, the females in his family decide when he will be replaced by a younger rival—though the male will do all he can do drive off such competition.

Gelada family units often combine to form large foraging bands of 30 to 350 animals. When food is abundant as many as 670 geladas have been seen together.

About 100,000 to 200,000 gelada monkeys survive, but even their remote mountain locales are feeling the effects of encroaching agriculture that threatens the grasslands. Indigenous peoples also hunt gelada and use their impressive manes in traditional coming-of-age ceremonies.

Aye-ayes

Aye-ayes can be found only on the island of Madagascar. These rare animals may not look like primates at first glance, but they are related to chimpanzees, apes, and humans.

Aye-ayes are dark brown or black and are distinguished by a bushy tail that is larger than their body. They also feature big eyes, slender fingers, and large, sensitive ears. Aye-ayes have pointed claws on all their fingers and toes except for their opposable big toes, which enable them to dangle from branches.

Aye-ayes spend their lives in rain forest trees and avoid coming down to earth. They are nocturnal, and spend the day curled up in a ball-like nest of leaves and branches. The nests appear as closed spheres with single entry holes, situated in the forks of large trees.

While perched aloft, the aye-aye taps on trees with its long middle finger and listens for wood-boring insect larvae moving under the bark. It employs the same middle finger to fish them out. The digit is also useful for scooping the flesh out of coconuts and other fruits that supplement the animal's insect diet.

Many people native to Madagascar consider the aye-aye an omen of ill luck. For this reason they often have been killed on sight. Such hunting, coupled with habitat destruction, have made the aye-aye critically endangered. Today they are protected by law.

Baboons

There are five different species of baboons. All of them live in Africa or Arabia. Baboons are some of the world's largest monkeys, and males of different species average from 33 to 82 pounds (15 to 37 kilograms). Baboon bodies are 20 to 40 inches (60 to 102 centimeters) long, not including substantial tails of varying lengths.

Baboons generally prefer savanna and other semi-arid habitats, though a few live in tropical forests.

Like other Old World monkeys, baboons do not have prehensile (gripping) tails. But they can and do climb trees to sleep, eat, or look out for trouble. They spend much of their time on the ground.

Baboons are opportunistic eaters and, fond of crops, become destructive pests to many African farmers. They eat fruits, grasses, seeds, bark, and roots, but also have a taste for meat. They eat birds, rodents, and even the young of larger mammals, such as antelopes and sheep.

Four baboon species (i.e., chacma, olive, yellow, and Guinea) are known as the savanna baboons. These animals form large troops, composed of dozens or even hundreds of baboons, governed by a complex hierarchy that fascinates scientists. Males use shows of physical power to dominate rivals, and troop members spend endless hours carefully grooming one another to remove insects and dead skin.

A fifth species, the hamadryas baboon, lives in the hills along the Red Sea coasts of Africa and Arabia. These cliff-dwelling baboons disperse to forage during the day and reconvene in much smaller groups at night.