A list of 800 animals and plants very close to being wiped out has been put together by researchers who want to highlight the danger they are in.
They've put their information on a map showing the places around the world where the species are found.
Most of the 800 are only found in one place, largely in the tropics.
Writing in a science magazine, the researchers say protecting some of these sites could cost as little at $1,000 (£560) a year.
Most of the animals and plants are under threat because they could lose their habitat, as many jungles and forests are being cut down by farmers or loggers.
Animals under threat include the Indian pygmy hog and the golden-crowned sifaka from Madagascar.
A total of 13 conservation organisations took part in the research, coming together in a group called the Alliance for Zero Extinction (AZE).
They aim to work together with people who live alongside the animals, showing them that it is important to keep them safe, and how things like tourism can actually make them cash.
AZE spokesman Stuart Butchart said: "It's impossible to know or predict how long these species might have; but certainly within the next few decades, if these sites aren't protected, they will be gone."