Many animals could be saved from extinction after researchers pinpointed the 20 areas in the world where they are most likely to die out.
Regions such as Greenland, the Caribbean islands and parts of South East Asia are home to animals that aren't at risk yet but soon could be.
In these areas the speed at which the creatures reproduce is slower than the pace at which humans are harming them.
Scientists plan to help the animals in these 'hot spots' before it's too late.
Researchers found that the animals at most risk tend to have large bodies, live in small areas and reproduce slowly. These include the North American reindeer, the musk ox, the Seychelles flying fox and the brown lemur.
Experts who compiled the list of at risk regions believe the animals living there could overtake animals that are currently considered to be close to extinction.
The leader of the study Dr Marcel Cardillo said: "We can see this leap-frogging happening now, for example with the Guatemalan howler monkey, which was classified as being on the 'least concern' list in 2000 but which moved to the 'endangered' list in 2004 as it lost much of its forest habitat."
1: Northern Canada and Alaska
3: Siberian tundra
4: Eastern Canadian forests
6: East Indian highlands
7: Southern Polynesia
8: Lesser Antilles
9: Andaman and Nicobar Islands
10: Borneo, Sulawesi, Moluccas
11: New Guinea
12: Patagonian coast
13: Peninsular Malaysia, Sumatra and West Java
14: Nusa Tengarra
15: Tasmania and the Bass Strait
17: Indian Ocean islands