Here's a look at just a few of the world's most endangered species:

Greater Horseshoe Bat

Rhinolophus ferrumequinum

IUCN Status: least concern

Population trend: decreasing

There are eighteen species of bat in Britain and all of them are endangered. The greater horseshoe bat is one of the rarest. One reason for their decline is the destruction of suitable roosting sites, such as old buildings and hollow trees. Changing land use from woodland and small fields to large scale agriculture has also had an effect. They have also suffered from the use of insecticides (poisonous chemicals sprayed on to crops to kill harmful insects) which have deprived the bats of their insect food. Due to conservation efforts its population in the UK has stabilized at about 5000.

Siberian (Amur) Tiger Panthera tigris ssp. altaica IUCN status: Endangered Population trend: stable