The Fossa: A Cat-Like Mongoose Relative in Madagascar
An Interesting Animal
The fossa (pronounced "FOO-sa") is the largest predator in Madagascar. It lives in forests, both in trees and on the ground, and is active in the day or at night. The animal is a fierce hunter and an excellent tree climber. It travels up and down trees and along branches with ease. It can also move rapidly over land.
The fossa was once thought to be a type of cat. Researchers have now concluded that it’s related to mongooses, despite having a body with several cat-like features and a dog-like muzzle. Its scientific name is Cryptoprocta ferox. "Crypto" comes from the Ancient Greek word for hidden and "procta" from the word for anus. The name refers to the fact that the animal's anus is hidden inside a pouch, which opens to the outside via a slit. "Ferox" comes from the Latin word for fierce.
Madagascar is the fossa’s only home in the wild. The IUCN (International Union for Conservation of Nature) classifies the animal's population as vulnerable due to the loss and fragmentation of its habitat. Animals in the vulnerable category are likely to become endangered if the factors hurting their population size aren’t changed.
Location of Madagascar: The Home of the Fossa
Approximately 95 percent of Madagascar’s reptiles, 89 percent of its plant life, and 92 percent of its mammals exist nowhere else on Earth.— World Wildlife Fund
The fossa belongs to the order Carnivora, like cats, dogs, and mongooses. At one time it was placed in the cat family (Felidae), but it's now placed in the family Eupleridae. It's thought to be more closely related to the African and Asian mongooses than to cats.
A fossa is a slender animal with an elongated body and a long tail. Its coat is usually reddish or golden brown in colour but is occasionally black. The belly is generally cream. The hair is short and dense. The animal has a projecting muzzle, rounded ears, a bulbous nose, and long whiskers. Its large eyes help it to see at night.
The fossa's head and body have a total length of around twenty-four to thirty-one inches. The long tail is about the same length as the head and body. Fossas weigh around fifteen pounds to twenty-four pounds. Females are generally shorter and lighter than males.
The fossa's hind legs are longer than its front legs, which enables it to leap from branch to branch in the trees. Its long tail helps it to balance as it jumps. A fossa has semi-retractable claws, like those of a cat. It also has flexible ankles that can bend through an angle of 180 degrees. This ability helps the animal cling to tree branches and walk head first down tree trunks. Fossas in captivity have been observed hanging upside down from ropes with just their hind feet attached to the rope.
Fossas walk on the soles of their feet, as we do, which is known as a plantigrade method of locomotion. Cats and dogs walk on their toes and are said to have digitigrade locomotion.
The fossa is a carnivorous animal. Its favourite food is lemurs. These may be almost as large as the fossa and are believed to make up over half of the animal's diet. Lemurs are primates, like us. As far as scientists know, the fossa is the only animal whose primary food is a primate.
Fossas also eat rodents and other small mammals, birds, reptiles, amphibians, and sometimes insects. They drink water from the small pools that they find on their travels.
Animals are categorized based on the time when they are most active. Nocturnal animals are active during the night, diurnal animals during the day, crepuscular animals at dawn and dusk and cathemeral animals—such as the fossa—at any time. The fossa is most active at night, however.
Fossas are usually solitary animals. They have sometimes been observed in pairs or small groups and have occasionally been seen engaging in cooperative hunting. They are ambush hunters and catch prey both in the trees and on the ground.
The animals are often hard to observe because they move so rapidly through the tree canopy, leaping from branch to branch. This makes it hard for biologists to learn about their lives in the wild. Researchers do know that the animals maintain a territory, which they mark with a secretion from their anal glands and, at least in males, from glands on their chest.
The animals communicate vocally as well as by scent. They make yelping, chirping, purring, snoring, and mewing sounds at different times, depending on the situation. They sleep in a den on the ground or in a hole in a tree.
Fossa Cubs or Pups
In the wild, fossas breed in September and October. Mating usually takes place in specific trees that are used each year, although it has also been observed taking place on the ground. A female may stay in her mating tree for up to a week and attract many males. The mating process may last for up to an hour or more per male. The female usually mates with multiple males before she descends from her tree.
The youngsters are born in the trees or in a ground den. A hollow in a tree, a rock crevice, an old termite mound, or a hole in the ground are favourite sites for dens. The babies are known as pups or cubs. Between two and four pups are born after a gestation period of around two months. The pups are helpless at birth and are unable to move around. Their eyes are closed and they have no teeth. Due to these characteristics they are said to be altricial. Precocial youngsters have relatively mature features at birth and can move around almost immediately.
Fossa pups are weaned at about four months old. They stay with their mother for at least twelve months and are ready to mate at around four years of age. Fossas in captivity live for about twenty years. Their lifespan in the wild may be shorter, however.
Enrichment Activity in a Zoo
Masculinization in Juvenile Females
One interesting feature of the fossa's development is the transient masculinization shown by a juvenile female when she is between eight and eighteen months old. Her clitoris temporarily becomes elongated and spiny, making her look like a male. She also releases an orange or red secretion on her undersurface like a mature male. By the time she reaches adulthood these features have disappeared. The reason for the female's temporary masculinization is unknown.
IUCN Red List Categories for Population Status
From left to right, the meaning of the red list categories shown above is as follows.
EW - Extinct
EW - Extinct in the Wild (but still exists in captivity)
CR - Critically Endangered
EN - Endangered
VU - Vulnerable
NT - Near Threatened
LC - Least Concern
Often two additional categories are added on the right—DD, or Data Deficient, and NE, or Not Evaluated.
Population Status of the Fossa
The IUCN maintains a “red list” of threatened animal species. Each species that has been assessed is assigned to a red list category based on its nearness to extinction. The latest assessment of the fossa population took place in 2015. The animal has been classified as vulnerable, since its numbers are decreasing. Though it seems to have quite a wide range, it appears to have a low population throughout the range.
The main reason for the decline of the fossa population is the destruction of forests in Madagascar. The land is being cleared for agriculture and logging. As a result, it's harder for fossas to find food. They sometimes prey on livestock, especially chickens, and risk being killed by farmers. In some areas they have a bad and perhaps undeserved reputation as a nuisance or even a dangerous animal. They are sometimes hunted as a pest or are killed for bushmeat.
The IUCN predicts that the fossa population will drop by around thirty percent over the next three generations. The animals can be seen at zoos in both Europe and North America and have bred in captivity. The wild population needs help, however.
The fossa is a distinctive and very interesting animal, just like much of the other wildlife of Madagascar. I hope that ways can be found to balance both the needs of humans and the needs of wildlife on the island.
© 2011 Linda Crampton