The fossa feeds mainly on lemurs and tenrecs (hedgehog-like species), and hides in trees.

When a female is in heat, she chooses a tree where several males will come to court her. Only one will mate with her on the end of a branch. This tree is often the same one from year to year. Female fossas have litters of 2 to 4 young, which they raise alone.

Looking at its semi-retractable claws and its tail which it uses for balancing, the fossa could be mistaken for a member of the cat family. But this is not the case for, contrary to appearance, it belongs to the Eupleridae family which includes the eight carnivores of Madagascar.