Ninety-nine percent of all forms of life that have existed on Earth are now extinct.

The last auroch, the wild ancestor of the cow, was killed in 1627 by a poacher on a Polish hunting preserve. (source)

The ivory-billed woodpecker is one of the most elusive animals. It was believed to be extinct since the 1930s due to the loss of its natural habitat, but in 2004 and 2005 it was sighted in Arkansas and Florida. Attempts to confirm these sightings have not been successful. (source)

Over the past 2,000 years, humanity has helped to cause the extinction of about 2% of the known species of the world's mammals. (source)

Brown bears used to be native to England, but became extinct there in the 11^th century. Later on in the Middle Ages, bears had to be imported into England for the mediaeval sport of bear-baiting. (source)

The Wake Island rail was only discovered in 1903 and was extinct by 1946. It was wiped out when the island was occupied during World War II by Japanese soldiers, who found it a tasty delicacy. (source)

The coelacanth, a member of a group of fishes that existed 350 million years ago, is still alive and can be found off the shores of southern Africa. It was thought to be extinct until 1938, when fishermen off the coast of South Africa caught one. (source)

Passenger pigeon.

The passenger pigeon, which became extinct on September 1, 1914, when the Cincinnati zoo's specimen, Martha, died, was the most abundant bird in the world in the nineteenth century and the most abundant ever in North America. Scottish-American ornithologist Alexander Wilson once watched a 250-mile-long flock pass over his Kentucky home for two whole days. In 1813, naturalist John James Audubon saw a flock that flew past at an estimated 300 million birds per hour for three days, blotting out the sun. However, due to vigourous hunting and destruction of their habitat, by the 1860s the birds had disappeared from the American east coast and were quickly disappearing everywhere else. The last big pigeon hunt took place in 1878 near Petoskey, Michigan, killing one billion birds. The last wild passenger pigeon was shot in St. Vincent, Quebec, on September 23, 1907. In 1909, a reward of $1,500 was offered for information on a nesting pair, and while it was believed for a few years that it might be possible to find the passenger pigeon in the remote Lake of the Woods region, none were found; the species was extinct. (source)

The only wild horses in the world are Przewalski's horses, from Mongolia. Although they became extinct in the wild in 1968, they have since been re-introduced to their native Mongolia. All other horse breeds are descended from horses that were once domesticated.

The Irish Elk or Giant deer was the largest deer ever. It became extinct somewhat less than 6,000 years ago; the latest known remains have been dated to about 5,700 B.C. At the shoulders the Giant Deer measured 7 feet in height. Its antlers were 12 feet from tip to tip and weighed up to 90 pounds. (source)

Perhaps the most famous extinct animal is the dodo, giving rise to the phrase "dead as a dodo". It was a peculiar-looking flightless bird that looked a bit like a duck with a large, hooked bill. It lived in Mauritius in the Indian Ocean. However, its inability to fly, its lack of fear for humans and its good taste caused it to be hunted to extinction in the 17th century. (source)

The zebra used to have a close relative called the quagga. The quagga only had stripes on its head and neck, not on its entire body like the zebra. It was hunted to extinction, with the last member of the species dying in captivity in 1883. It became the first extinct animal to have its DNA studied when its DNA was extracted from mounted specimens in 1984. (source)

The heath hen was quite commonplace in New England in the 1600s. During breeding season, it nested on the ground and would stay there, guarding its nest, even when threatened. That made them easy targets for the Puritan inhabitants of New England, who ate the bird so frequently that they grew tired of it, and the dish was relegated to servants. By 1880, the heath hen could only be found in Martha's Vineyard, off the coast of Massachusetts. By 1932 the bird was extinct. (source)

There is only one recorded battle in which both sides used elephants. In the Fourth Syrian War, in 217 B.C., Antiochus III of Syria used Asian elephants when attacking Ptolemy IV's Egyptian army with its smaller North African elephants (now extinct). While the Asian elephants were victorious, the Egyptian army would go on to win a smashing victory at Raphia on the Egyptian border. (source)

In the early 1980s, due to the risk of swine fever, all of the native Haitian pigs, which were descended from mediaeval European pigs brought to Haiti during the seventeenth and eighteenth century, were eradicated by Haitian dictator Jean-Claude Duvalier. French scientists later "re-created" the extinct Haitian pig by crossing Chinese pigs with Caribbean and mediaeval Gascon breeds. When the Duvalier regime fell, the French sent their creation to Haiti.

The lions used by the Romans in the Colosseum were Barbary lions, whose manes covered nearly half of their bodies. While the export of lions to Rome threatened their population, greater damage was done after Roman times, when they were killed by Arabs, encouraged by governments that exempted tribes that killed lions from taxation. The Barbary lion's last stronghold was in the Atlas Mountains, where the last true Barbary lion was killed in 1922. (source)

The island of Mauritius in the Indian Ocean is the home of the tambalacoque tree, which, until the 17^th century, flourished in the hot and humid climate. Then, all of a sudden, the tree seemed to lose the ability to grow from seed. No reason was found, with the result that, by the 1970's, there were only 13 very old tambalacoque trees left. It was then that an American ecologist, Stanley Temple, noticed that the tambalacoque had stopped growing from seed at precisely the time when the dodo became extinct. Many seeds will germinate only after having been eaten by a particular animal and passing through its digestive system. As an experiment, Temple fed tambalacoque seeds to turkeys and gathered seeds up from their droppings. Some of these seeds did germinate, and there is hope that the tambalacoque tree will survive.