With reddish-brown fur, an elongated, muscular and agile body; The fossa is the largest endemic carnivore on Madagascar and the island's dominant predator. Its size is similar to that of two domestic cats and the male is slightly larger than the female. Its appearance is similar to that of a jungle cat, in fact, for a long time it was classified among felines, but it really descends from some type of civet.

It is primarily arboreal, although it is also comfortable on the ground. It can run at high speed and easily climb trees thanks to its powerful muscles, its long tail and strong retractable nails that serve as a grip. They are solitary and territorial animals. Both the female and the male mark their territory through secretions from powerful scent glands. They tend to be nocturnal, especially when hunting, as they have very keen vision, as well as sense of smell and hearing.

Man is the main predator of the fosa. He usually hunts her to prevent her from feeding on his livestock, such as guinea fowl, and other animals. This, together with the destruction of Madagascar's wild habitat, places the trench in a threatened state of conservation.