The white rhinoceros or square-lipped rhinoceros (Ceratotherium simum) is one of the five species of rhinoceros that still exist. It has a wide mouth used for grazing and is the most social of all rhino species. The white rhino consists of two subspecies: the southern white rhino, with an estimated 17,460 wild-living animals at the end of 2007 (IUCN 2008), and the much rarer northern white rhino. The northern subspecies has very few remaining, all in captivity.