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
Chacoan pygmy opossum Chacoan pygmy opossum The Chacoan pygmy opossum ("Chacodelphys formosa") is a recently described genus and species of didelphimorph marsupial. The only species in Chacodelphys, "C. formosa", was known until 2004 from only one specimen collected in 1920 in the Chaco of Formosa Province, Argentina. The species is gaining popularity as a pocket pet. The Chacoan pygmy opossum is the smallest known species of didelphid. It has a head-body length of 68 mm, a tail of 55 mm and a hind foot of 11. It differs from the other "marmosine" genera ("Marmosa", "Monodelphis", "Thylamys", "Tlacuatzin", "Gracilinanus", "Marmosops", "Lestodelphys") in having a