The white rhinoceros, Ceratotherium simum, or square-lipped rhinoceros is the largest extant species of rhinoceros. It has a wide mouth used for grazing and is the most social of all rhino species. The white rhinoceros consists of two subspecies: the southern white rhinoceros, with an estimated 20,405 wild-living animals in 2013, and the much rarer northern white rhinoceros. The northern subspecies has very few remaining, with only four confirmed individuals left, all in captivity.