First things first — what even is a fossa? Is it a cat? A dog… or perhaps a giant weasel?

Actually, it’s none of the above. Fossas are classified as Malagasy carnivorans, also known as Eupleridae. In plain English, they’re mongoose-like mammals endemic to Madagascar. Scientists believe that this animal evolved from an ancient African ancestor around 20 million years ago.

Today, Madagascar is home to a smaller fossa species. The two fossas were morphologically identical — meaning they look exactly alike. However, their difference in size classifies them as two separate, sibling species.

Let’s step into a mental time machine and take a look at ancient Madagascar. This is a fascinating place, teeming with giants. It’s an isolated landmass, where you’ll find creatures unlike anything else on Earth. One of these animals being the giant fossa.


This carnivore dwelled primarily in the humid forests of Madagascar. The rainforests extended from the mountainous central highlands down to the coastal lowlands.

Subfossil bones (not fully fossilized) were discovered in the caves of Madagascar. This suggests that the giant fossa lived in dens. On the other hand, the living fossa sometimes sleeps on tree limbs. So we can assume that the giant fossa did the same.


Living fossas are about 6 ft in length (including tail), but the giant could grow over 7 ft long. This is comparable to the size of a full-grown gray wolf. Their tails were particularly long, making up for about half of this length.

Giant fossa coats were short, sleek, and almost entirely monochrome brown. They had cat-like features, including long whiskers and sharp claws and teeth. However, fossas’ snouts protrude further outwards, much like their mongoose cousins. They also have longer, more slender bodies than you’d see on most big cats.


Fossil evidence found in underwater caves suggests that it preyed on giant lemurs. This is thought to have once been a giant fossa’s den, as the cave was not always submerged.

Go back into that mental time machine of yours; try to imagine these ancient Madagascar lemurs — as big as gorillas! This explains why the giant fossa was armed with such massive jaws. Even to this day, living fossas continue to hunt (much smaller) lemurs.

It’s also assumed that it preyed on a few other creatures, including rodents, reptiles, birds, and fish. These are a few of the modern-day fossa’s favorite meals, after all. Giant fossas are thought to have hunted both during day and night, categorizing them as cathemeral.


Although they are solitary hunters, today’s fossas have been observed sharing their catch. Scientists believe that this is indicative of the extinct giant fossa’s behavior. Cooperative hunting could have been used to tackle the much larger lemurs of earlier times.

There is not a lot of evidence to explain the true nature of giant fossas. However, there is a bit of interesting folklore. French governor of Madagascar, Étienne de Flacourt, described a “large, rare, leopard-like carnivore that eats men and calves and lives in remote mountainous areas.” To this day, there seems to be a looming fear of the fossa amongst the Malagasy natives.


It’s unknown exactly when the giant fossa went extinct, but scientists believe it happened sometime before the 1650s. This made it the only known carnivoran mammal to go extinct in Madagascar.

Early French migration to Madagascar led to a great deal of habitat destruction. On top of this, giant lemurs had eventually disappeared. With the loss of both habitat and its main prey, the giant fossa, too, went extinct.