The cheetah (Acinonyx jubatus) is a large feline (family Felidae, subfamily Felinae) inhabiting most of Africa and parts of Iran. It is the only extant member of the genus Acinonyx. The cheetah can run faster than any other land animal— as fast as 112 to 120 km/h (70 to 75 mph) in short bursts covering distances up to 500 m (1,600 ft), and has the ability to accelerate from 0 to 100 km/h (62 mph) in three seconds.[9] The cheetah is a unique felid, with its closest living relatives being the puma and jaguarundi of the Americas. This cat is notable for modifications in the species' paws, being one of the few felids with only semi-retractable claws.[10] Its main hunting strategy is to run down swift prey such as various antelope species and hares. Almost every facet of the cheetah's anatomy has evolved to maximise its success in the chase, the result of an evolutionary arms race with its prey. Due to this specialisation, however, the cheetah is poorly equipped to defend itself against other large predators, with speed being its main means of defence. In the wild, the cheetah is a prolific breeder, with up to nine cubs in a litter. The majority of cubs do not survive to adulthood, mainly as a result of depredation from other predators. The rate of cub mortality varies from area to area, from 50% to 75%,[11] and in extreme cases such as the Serengeti ecosystem, up to 90%. Cheetahs are notoriously poor breeders in captivity, though several organizations, such as the De Wildt Cheetah and Wildlife Centre, have succeeded in breeding high numbers of cubs.