. >> accccordingng to the internatioional union for conservation of nature and natural resources' redenearly 24,000 0 animal and p t species are under threat of extinction. and almost always, people are to blame. but how do we know which species are at risk? how is the red list drawn up? we went to kirindy forest in madagascar to talk to scientists working on the lemur red list. >> the forest at night. during the day it's very hot in this dry finalist western madagascar. most animals here are nocturnal, including some species of camimillian and the e mouse lem. >> vision is so important for us humans so it is amazing to walk through the forest at night and to imagine how all these animals get about, find food or the next branch. >> nine species of lemur live in this forest. peter has been researching them for 20 years. every morning he and his team drive to kirindy forest to gather data -- for their research on lemurs, and for the red list. almost all species of lemur are endangered. the team observe the animals, track their movements, and collect samples of their feces. this informat