Pygmy hippopotamus population that freely breeds in zoos around the world. Between 1970 and 1991 the population of pygmy hippos born in captivity more than doubled. The survival of the species in zoos is more certain than the survival of the species in the wild. In captivity, the pygmy hippo lives from 42 to 55 years, longer than in the wild. Since 1919, only 41 percent of pygmy hippos born in zoos have been male. While the common hippopotamus was known to Europeans since classical antiquity, the pygmy hippopotamus was unknown outside its range in West Africa until the 19th century. Due
Mountain pygmy possum is hairless. On the underside of the female's body is a pouch containing four teats. This possum is the only extant species in the genus "Burramys". It is also the only Australian mammal restricted to alpine habitat. The mountain pygmy possum was first discovered in the fossil record in 1895 when a portion of the jaw and skull bones were found in the Wombeyan Caves in central New South Wales. At the time, the species was believed to be extinct. It was not until 1966 that a living individual was found at a ski resort at Mount Hotham in Victoria.