Scientists have called for called for governments to do more to protect primates.
It's after warning that more than half the world's primate population is facing extinction.
A new list of the world's 25 most endangered primates has been published.
The population has been decreasing for a number of reasons, including the burning and clearing of tropical forests.
Primates are also being hunted for food or for use in traditional medicine in Asia.
There are more 700 different types of primates in the world.
The Philippine tarsier and the Lavasoa Mountains dwarf lemur from Madagascar have been added to the list for the first time.
The hope is to convince governments across the world to look at ways of better protecting habitats and the animals.