Meet the Fosa

It was dusk in the dry forests of western Madagascar, and just outside the thin walls of my one-room cabin came extremely loud and repeated gasping – uh-HUNHHHHHH, uh-HUNHHHHHHH, uh-HUNHHHHH – that ended each time with a sort of wild bellow. It was, clearly, not human.

Thus began my introduction to the fosa (Cryptoprocta ferox), found only in Madagascar, and a candidate for one of Earth’s strangest but most fascinating animals. Overall, a fosa looks like a small and very sleek brownish-black panther, although it actually is more closely related to the mongoose and civets and weighs only about 7-12 kg (15-25 lbs).

After decades of controversy, researchers have only recently decided on the fosa’s (formerly fossa’s) scientific classification, in its own family with a small group of other Malagasy carnivores. In addition to long whiskers, it has retractable claws like a cat, which makes it an excellent tree climber. Yet it walks on the soles of its slightly webbed feet like a bear. It has a short, pointed muzzle resembling that of a dog.

Adding to its highly unusual nature, a fosa can even climb down a tree head-first using its “reversible” ankles, which have tremendous gripping power. Adolescent females go through a “masculine” phase in their development, when their sexual organs temporarily appear to resemble a male’s.

A very swift and agile carnivore – and the largest predator on the island – the fosa has been aptly described as “a lemur’s worst nightmare,” since the well-known primates comprise more than half of its diet. As a voracious predator that hunts mostly at night, it sees, hears and smells very well.

Outside my cabin in the Kirindy Forest, barely 6m (20 ft) from me, were not just one, but two, fosas. One was a male, the other female; fortunately, they ignored me. The male was on his hind legs, stretching up along the trunk of a tree and looking like he was scent-marking it. For balance, he was using his extremely long tail – at up to 1m (3 ft) by itself, almost the same length as his body.

Suddenly the two fosas lunged at each other, and there ensued what can only be described as an old-fashioned, and prolonged, catfight. They snapped. They screamed. They rolled in the dirt, snarling and slashing. Finally, the female ran off, and the male was left alone to forlornly rub against the tree again,

Later, I learned that the male, although it was the “off” season, was trying to get the female interested in breeding. (This activity, which usually occurs high in the trees, may last up to 3 hours for a single session.) She wasn’t having any of it – and made sure he knew that he wasn’t going to be lucky.

Few people outside Madagascar have even heard of fosas, much less had the privilege of seeing these rare and splendid creatures in the wild. The fosa fight itself also was unusual: Fosas are generally solitary. These two likely were around the camp because it was winter, and food was scarce overall.

Although fosas are found in forests and woodland savannas all over Madagascar, their population densities are usually very low. Fewer than 2,500 fosas are thought to exist in the wild. It is believed the population size has declined by at least 30 percent since the late 1980s. Equally alarming, it also is believed that no protected areas support a viable population, which would be needed for the species as a whole to survive.

Since 2008, fosas have been listed as vulnerable to extinction by the International Union for the Conservation of Nature (IUCN); according to some estimates, extinction may occur within 100 years. Clearly, urgent measures are needed to secure the fosa’s future.

The fosa is particularly threatened by the rapid disappearance of Madagascar’s forests and the severe fragmentation of its forest habitat. Some 90 percent of the country’s forests have vanished in the last 50 years, largely as a result of slash-and-burn clearing of land for agriculture as well as from illegal logging for rare tropical timber.

Humans are by far the fosa’s worst threat – even more so in a country ranked among the poorest in the world in terms of human development and still beset by political turmoil following a coup in 2009. People are not only responsible for the extreme deforestation, but they often hunt fosas to keep them from killing their cattle, goats or chickens. In some places villagers eat fosas, although in others the fosas may be protected by traditional taboos, known as fady.

As if all this weren’t enough, the fosa is further threatened by the plunging populations of various species of lemurs, which in July 2012 were rated by the IUCN as the most endangered mammals on Earth. If fosas’ favorite food disappears, clearly the predators will be in even deeper trouble than they already are.

But just hours after the fosa fight outside my cabin, at least one fosa – perhaps even the same male – was hoping to get lucky again, in a different sort of way. During a night walk in the Kirindy Forest, several Rainforest Connection members were startled by the thunderous shrieking of lemurs. Beneath the trees, stalking its prey, was a very intent fosa. The outcome of its hunt that night is unknown, but almost inevitably a fosa gets whatever it’s after. And that’s good: The strange but majestic fosa is going to need all the luck it can get.

K.K. Dorji, a writer/editor and international development practitioner, joined the Rainforest Connection on a recent monthlong trip to Madagascar to study the island’s unique wildlife.