The white rhinoceros is the largest of the five living species of rhinoceros. By mean body mass, the white rhinoceros falls behind only the three extant species of elephant as the largest land animal and terrestrial mammal alive today. It weighs slightly more on average than a hippopotamus despite a considerable mass overlap between these two species. It has a massive body and large head, a short neck and broad chest.
The head and body length is 3.7 to 4.5 m (12.1 to 14.8 ft) in males and 3.4 to 3.65 m (11.2 to 12.0 ft) in females, with the tail adding another 70 cm (28 in) and the shoulder height is 170 to 186 cm (5.58 to 6.10 ft) in the male and 160 to 177 cm (5.25 to 5.81 ft) in the female. The male, averaging about 2,300 kg (5,070 lb) is heavier than the female, at an average of about 1,700 kg (3,750 lb). The largest size the species can attain is not definitively known; specimens of up to 3,600 kg (7,940 lb) are considered reliable, while larger sizes up to 4,500 kg (9,920 lb) have been claimed but are not verified. On its snout it has two horn-like growths, one behind the other. These are made of solid keratin, in which they differ from the horns of bovids (cattle and their relatives), which are keratin with a bony core, and deer antlers, which are solid bone.
The front horn is larger and averages 60 cm (24 in) in length, reaching as much as 150 cm (59 in) but only in females. The white rhinoceros also has a noticeable hump on the back of its neck. Each of the four stumpy feet has three toes. The color of the body ranges from yellowish brown to slate grey. Its only hair is the ear fringes and tail bristles. White rhinos have a distinctive broad, straight mouth which is used for grazing. Its ears can move independently to pick up sounds, but it depends most of all on its sense of smell. The olfactory passages that are responsible for smell are larger than their entire brain. The white rhinoceros has the widest set of nostrils of any land-based animal.
