According to the International Union for Conservation of Nature, around one in four of the world's mammals are at risk of extinction.
Some 8,462 species are threatened to some extent, including mammals, birds, reptiles, insects and fish.
One in every three of the world's amphibian species, and one in eight of all species of birds are at risk too.
By 2008 the IUCN said it had studied almost 45,000 different species.
Of those, almost four in every 10 species are threatened and 804 of them are classified as extinct.
*We got this information from the 2008 Red List, an annual report by the International Union for Conservation of Nature.