They can be found only in the tropical rainforests of the Madagascar. Fossa is the largest predator on the island and it does not have natural enemies, but due to extreme deforestation (90% of the forest is already destroyed) it is listed as an endangered species.Less than 2500 animals are left in the wild.ossa is carnivore and 50% of its diet is composed of lemurs. They hunt any of 30 different species of lemurs that reside the Madagascar. Besides lemurs, fossa also eats small mammals, birds, fish, lizards, frogs and domestic animals (such as chickens).