The fossa is a cat-like, carnivorous mammal, that lives in Madagascar. It is a member of the Eupleridae, a family of carnivores closely related to the mongoose family.
The fossa is the largest mammalian carnivore on the island of Madagascar and has been compared to a small cougar. Adults have a head-body length of 70–80 cm (28–31 in) and weigh between 5.5 and 8.6 kg (12 and 19 lb), with the males larger than the females. It has semiretractable claws and flexible ankles that allow it to climb up and down trees head-first, and also support jumping from tree to tree. The fossa is unique within its family for the shape of its genitalia , which share traits with those of cats and hyenas.