Madagascar's largest carnivore, the fossa is an unusual member of the civet family. It hunts lemurs in trees at night and has a strange courtship and breeding system.

Life span
Probably around 17 years.

Statistics
70cm long, with a long tail the same length as the body. Weighs between 9.5 and 20kg.

Physical description
A member of the civet family, the fossa is Madagascar's largest carnivore. It has a cat-like head with large eyes, a short muzzle and large rounded ears, and a lithe body with a long tail. Its coat is short and reddish-brown all over. It has retractile claws and webbed feet.

Distribution
Madagascar.

Habitat
Rainforest.

Diet
Lemurs make up more than half the fossa's diet. The rest is made up of birds and other small mammals and reptiles.

Behaviour
Fossas spend much of their time in trees, sleeping during the day and hunting agile lemurs by night. They also hunt on the ground, where they walk with their palms flat on the ground like bears rather than on their toes like dogs, cats and other civets. They are mostly solitary except during the breeding season.

Reproduction
Fossas have an unusual mating system. Breeding occurs in September and October when females attract a large number of males. The female takes residence on a high branch in a tree, and males call up to her and fight with each other. The female mates with several males for long periods of time over a week. Mating takes a long time in each case because the male's penis is barbed and so there is a mating lock like that seen in dogs. After a week the female leaves, and another female takes her place, mating with the assembled males.

Gestation is 3 months, and 2-4 young weighing 80-100g are born in a tree or ground den. They develop slowly, with their eyes only opening 16-25 days after both and no solid food being eaten for 3 months. The young wean after 4 months but continue growing until they are 2 years old. They do not reach sexual maturity until they are 4 years old.

During their development, female fossas go through a strange period of 'masculinization' in which their clitoris develops like a penis and they secrete a bright orange substance like that seen in adult males. It is not known whether this is a unique feature of fossas or whether some of the other little-studied civets also go through this stage.

Conservation status
As with much of Madagascar's unique fauna, the fossa is listed as Endangered, mainly through loss of habitat.

Voice
Males call during the breeding season.