The fossa (Cryptoprocta ferox) is a slender, long-tailed, cat-like mammal that is endemic to Madagascar. The fossa is the largest mammalian carnivore on Madagascar. Its head-body length is 70-80 cm and its tail is 65-70 cm long. There is some sexual dimorphism, with adult males (weighing 6.2-8.6 kg) being larger than females (5.5-6.8 kg). It has semi-retractable claws (meaning it can extend but not retract its claws fully) and flexible ankles that allow it to climb up and down trees head-first, and also support jumping from tree to tree.