Tuesday, April 30, 2013

F is for FOSSA

The fossa (Cryptoprocta ferox) is a cat-like, carnivorous mammal that is endemic to Madasgascar.  It is a member of the Eupleridae, a family of carnivorans closely related to the mongoose family (Herpestidae).  Its classification has been controversial because its physical traits resemble those of cats, yet other traits suggest a close relationship with viverrids (most civets and their relatives).  Its classification, along with that of the other Malagasy carnivores. influenced hypotheses about how many times mammalian carnivores are most closely related to each other (forming a clade, recognised as the family Eupleridae).  Carnivores are how thought to have colonised the island once around 18 to 20 million years ago.

The fossa is the largest mammalian carnivore on the island of Madagascar and has been compared to a small cougar.  Adults have a head-body length of 70-80 cms (28-31 in) and weigh between 5.5-6.8 kg (12-19 lb), with males larger than the females.  It has semi-retractable claws and flexible ankles that allow it to climb up and down trees head-first, and also support jumping from tree to tree.  The fossa is unique within its family for the shape of its genitalia, which share traits with those of cats and hyenas.

The species is widespread, although population densities are usually low.  It is found solely in forested habitats, and actively hunts both by day and night.  Over 50% of its diet consists of lemurs, the endemic primates found on the island; tenrecs, rodents, lizards, birds and other animals are also documented as prey.  Mating usually occurs in trees on horizontal limbs and can last for several hours.  Litters range from one to six pups, which are born blind and toothless (altricial).  Infants wean after 4-5 months and are independent after a year.  Sexual maturity occurs around three to four years of age, and life expectancy in captivity is 20 years.  The fossa is listed as "vulnerable" by the International Union for Conservation of Nature (IUCN).  It is generally feared by the Malagasy people and is often protected by their taboo, known as 'fady'.  The greatest threat to the species is habitat destruction.

The above shows the distribution of the fossa on the island od Madagascar.

An extinct relative of the fossa was described in 1902 from subfossil remains and recognised as a separate species, Cryptoprocta spelea, in 1935.  This species was larger than the living fossa (with a body mass estimated as twice as great), but otherwise similar.  Across Madagascar people distinguish two kinds of fossa - a large 'fosa mainty' (black fossa) and the 'fosa mena (reddish fossa) - and a white form has been reported in the southwest of the island.  It is unclear whether this is purely folklore or individual variation - related to sex, age or instances of melanism and leucism - or whether there is indeed more than one species of living fossa.

Melanism = the condition of having a high amount of dark or black pigment granules in the skin, hair, eyes etc.
Leucism = In zoology, whiteness resulting from lack of colouring; albinism, partial or complete; a technical term correlated with melanism and erythrism.

I was disappointed to learn that the lemur was one of the creatures that the fossa hunts as I am rather fond of lemurs but I guess it's all part of nature in the wild which one has to accept.


  1. Like you I am a fan of lemurs. Madagascar seems to have some quite distinctive wildlife. Quite of lot of it vulnerable. Sigh.
    This is a fascinating series - thank you.

  2. Once again, EC, thank you for your compliments re the series. I am having fun, like you, learning so much about these animals.
    I am thinking perhaps "L" may be about lemurs unless there is an Aussie animal suitable. Perhaps a double up again? Who knows.

  3. Amazing how many creatures are 'cat like' in their appearance. I guess there are only so many variations on a theme.

    1. From the very tiny to the extra large there is no mistake their shape or form.

  4. There's a lot of wildlife on that small island. But now I'll worry about the Lemurs too, they're such cute little monkeys. Then again, the Fossa need to eat too.....the whole circle of life thing, it must go on.

  5. Mankind I think is the biggest threat to all the animal species on Madagascar. It's called progress whereas with the creatures themselves it's all part of nature itself.