The polar bear and hippopotamus are for the first time listed as species threatened with extinction by the world’s biodiversity agency. They can still be saved. But for other unfortunate species, there is no chance – they have become permanently extinct. A survey conducted among biologists conducted by New York’s American Museum of Natural History, 70% of biologists we are undergoing the early stages of a human-caused mass extinction, known as the Holocene extinction event. What are the species we have lost?

- Caspian Tiger - Of all the tigers known to the world, the Caspian tiger was the third largest. It is commonly stated that the Caspian tiger finally disappeared sometime in the late 1950s; the year given is usually 1959 and the accompanying information often makes reference to the last specimen as having been shot in Golestan National Park, Iran. Yet other reports state that the final Caspian tiger was captured and killed in Northeast Afghanistan in 1997. Hunting, and loss of habitat and large wild prey are the primary causes of the loss of the subspecies.

- Dodo bird – Around 1505 the Portuguese became the first Europeans to discover the dodo. By 1681 it had been driven to extinction by humans and the feral dogs, pigs, rats, and monkeys introduced by Europeans to Mauritius. The last one was killed in 1681. Having evolved over millions of years to take maximum advantage of its splendid isolation, its size and inability to flee from predators ushered it into extinction in an evolutionary instant. Although the tale of the dodo’s demise is well documented, no complete specimens of the bird were preserved; there are only fragments and sketches.

- Great Auk - A strong swimmer, the great auk wintered as far south as Florida and southern Spain. The last authenticated sighting of this species was from Fire Island off the coast of Cape Reykjanes, Iceland, on June 3, 1844. At that time a pair of adult Great Auks were caught and killed by collectors. The adults had laid an egg and were incubating. Today, around 75 eggs of the Great Auk remain in museum collections, and about again this number of skins.

- Steller’s Sea Cow - Although they look rather like whales or sea lions, the order’s closest relatives are elephants and hyrax. The Steller’s Sea Cow was slaughtered for its meat and leather. They grew as large as 35 feet long and weighed up to three-and-a-half tons. It was discovered in the Bering Strait in 1741 by the naturalist Georg Steller and vanished from their only home within 30 years after Steller’s discovery.

- Tasmanian Tiger - This is one of the most fabled animals in the world and was the largest known carnivorous marsupial of modern times. The arrival of European settlers marked the start of a tragic period of conflict that led to the tiger’s extinction. The last known member of the species died in Hobart Zoo on 7th September, 1936. Ever since that specimen died in captivity, there have been sporadic but unconfirmed reports of tigers being sighted in the wilds near their old habitats. Most of the recent reports of Tasmanian Tigers come from the Island of Tasmania, a state of Australia, which lies just south of the eastern portion of the continent.

- Quagga - This is an extinct subspecies of the plains zebra, which was once found in great numbers in South Africa’s Cape Province and the southern part of the Orange Free State. When the Quagga mare at Amsterdam Zoo died on 12 August 1883, it was not realised that she was the very last of her kind. Because of the confusion caused by the indiscriminate use of the term “Quagga” for any zebra, the true Quagga was hunted to extinction without this being realised until many years later. A selective breeding programme was started in 1987. This aims to retrieve the Quagga genes, and to eventually produce individuals that will be comparable to the very varied 23 preserved Quaggas in the world’s museums.

This are only a few of the valuable species we have lost. For a list of the extinct species so far, visit AboutExtinction.com. Here are some quick facts about extinction today:

- 137 species are estimated to go extinct each day
- 50,000 species are estimated to go extinct each year
- There are more than 1,000 animal species endangered worldwide.