The fossa (Cryptoprocta ferox) is the largest carnivorous mammal on the island of Madagascar.It looks like a cross between a cat, a dog, and a mongoose. Fossas have slender bodies, muscular limbs, and short, reddish-brown coats. They have small, cat-like heads, short, dog-like muzzles, and large, rounded ears.So what is a fossa? Read my latest Zoologic post: The Creature Feature: 10 Fun Facts About the Fossa.