A northeastern spotted dolphin.

Aristotle noticed that dolphins give birth to live young who were attached to their mothers by umbilical cords, so he classified dolphins as mammals in Generation of Animals. Not until the nineteenth century did modern science confirm his statement. (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)

According to Roman historian Suetonius, it was rumoured that one consul and coregent of Rome was a horse—Emperor Caligula's favourite, Incitatus, who was accorded honour at every turn. Caligula's successor, Claudius, did not invite Incitatus in to dine, as had Caligula, but the horse was still decently treated, having an ivory manger and a golden drinking goblet for partaking of wine. (source)

Horses were not commonly used for farm work until the twelfth century, because the chest harness in use since Roman times was inefficient. The invention of the shoulder harness, the "horse collar," enabled them to pull much greater weights, such as farm implements. (source)

The fourth Moghul Emperor, Jahangir, who ruled from 1605 to 1627, had a harem of 300 royal wives, 5,000 additional women, and 1,000 young men. His stables contained 12,000 elephants, 10,000 oxen, 2,000 camels, 3,000 deer, 4,000 dogs, 100 tame lions, 500 buffalo, and 10,000 carrier pigeons. (source)

Lord Byron kept a pet bear at Cambridge University because dogs were not allowed. (source)

A well-intentioned philanthropist, Eugene Scheifflin, instituted a project in 1890 to bring to America each type of bird mentioned in the works of Shakespeare. In Act 1 scene 3 of Henry IV, Part I Hotspur says, " Nay, I'll have a starling shall be taught to speak / Nothing but 'Mortimer,' and give it him / To keep his anger still in motion," so starlings were let loose in New York's Central Park. There are now hundreds of millions of starlings throughout all of North America, from Alaska to Mexico, bullying and displacing many native species of songbirds. (source)

The Dingo is the only wild, carnivorous animal that is native to Australia.

Until recently, the only purple animal known was the blesbok, a small South African antelope. However, in 2003 a small purple frog was discovered in Western India. It spends most of the year up to 12 feet underground, which is why it was not discovered earlier. (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 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.

A group of magpies is called a tiding, one of ravens an unkindness, one of turtledoves a pitying, one of starlings a murmuration, one of swans a lamentation, one of ponies a string, one of rattlesnakes a rhumba, one of crows a murder, one of cobras a quiver, one of foxes a skulk, one of emus a mob, one of elks a gang, one of cats a clowder, one of flamingoes a pat, and one of bears a sleuth. Groups of geese are named in a peculiar manner; when they are on the ground they are called a "gaggle", but in the air they are called a "skein". (source)

The eye of an ostrich is larger than its brain.

Some crabs near Danno-ura in Japan have patterns on their shells bearing an uncanny resemblance to a face of a samurai. When caught, these crabs are thrown back in commemoration of the Heike samurai clan, who lost a naval battle there in 1185. The patterns on the crabs' shells are inherited, and it is believed that the patterns evolved because fishermen tended to throw back crabs with patterns resembling faces. So, crabs with patterns that most resembled a face had a better chance of surviv­al. Eventually, the pattern of a fierce, scowling samurai face evolved. (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)

A frozen woolly mammoth found on the banks of the Beresovka River, in Siberia, was in an almost complete state of preservation. Investigating scientists were able to eat its meat, and buttercups were found in the creature's mouth. (source)

Winnie-the-Pooh is based on a real bear. On August 24th, 1914, a Canadian soldier and veterinarian named Harry Colebourn, en route to a training camp in Valcartier, Quebec, purchased an orphaned black bear cub for $20 in White River, Ontario, which he named Winnipeg, or Winnie for short. When his unit was sent over to France during World War I, Colebourn loaned her to the London Zoo, intending to take her back to Canada after the war. However, Winnie's gentle disposition made her the zoo's top attraction, and on December 1, 1919, he donated her to the zoo. In the mid 1920s, writer A. A. Milne often took his young son, Christopher Robin, to the zoo, and Christopher named his teddy bear "Winnie-the-Pooh" after Winnie. A. A. Milne went on to write several best-selling children's books about Christopher Robin and Winnie-the-Pooh.

Apart from humans, the Asian elephant is the only mammal that can stand on its head.

A cockroach can live without its head for over a week, until it dies due to lack of food or water.

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)

From 1890 to 1900, 20 tons of ivory taken from the remains of woolly mammoths were shipped each year from Siberia to London.

In Barnsley, England, in 1984, Percy, a Chihuahua, accompanied his owner, Christine Harrison, on a visit to her parents' home. Percy refused to stay in the yard, darting into the street, where he was hit by a car. The dog displayed no signs of life, so Christine asked her father to bury her pet. Percy was put in a heavy paper sack and entombed in a two-foot-deep grave in the garden. However, Mick, a terrier belonging to Christine's parents, refused to leave the grave. He dug up Percy, dragged him to the house, and stimulated his circulation by licking him. Percy was still unconscious but now had a faint heartbeat, and he eventually recovered. Interestingly enough, Percy and Mick hated each other, and continued to do so after this incident.

Hummingbirds can't walk.

An elephant can achieve a speed of twenty miles an hour, and sustain it for half a day. (source)

There is a species of jellyfish, Turritopsis nutricula, called the "immortal jellyfish", that can theoretically live forever. Unlike other species of jellyfish that die after reaching maturity, the immortal jellyfish is able to revert to an immature polyp state and begin maturing again. It can in theory repeat the process indefinitely. (source)

The largest recorded specimen of the blue whale is 33 meters (110 feet) long—about the height of an 11-storey building. (source)

The Romans were so fond of eating dormice that the upper classes raised them domestically. The rodents were kept in specially designed cages and fed a mixture of nuts.

Three pairs of common English rabbits were let loose in Australia in the middle of the nineteenth century. Within a decade, the six rabbits had multiplied into millions, menacing the country's agriculture.

India has a bill of rights for cows.

The only mammal with a poisonous bite is the short-tailed shrew.