Black rhinos live more solitary lives than their white rhino cousins, though they sometimes form groups called crashes. Adult males typically live alone, meeting with females to breed. A mature, dominant male may tolerate subordinate males in his territory, but young adults or old males who can no longer defend themselves often die in fights with dominant males. Females live by themselves unless they have a calf. Occasionally, a female will allow an older offspring to rejoin her when a new calf is six to eight months old.
Rhinos have very poor eyesight, so they depend on their acute hearing and keen sense of smell to communicate, using both sound (sniffs, snorts, and grunts) and scent. Males and females mark their territories by spraying urine, which they can project as far as 12 feet (3.7 m)! They also mark territory with piles of dung and by rubbing a scent gland on their head against rocks or trees.
For such a large animal, black rhinos can run unexpectedly fast: up to 34 miles per hour (55 kph). They weave in sharp, unexpected turns and plow through shrubs like a tank. These rhinos have a reputation for being aggressive when threatened. They can be active during the day or night. They spend the heat of the day out of the sun and often wallow in mud, coating their skin with a natural bug repellent and sunblock. Black rhinos live in and defend home ranges and move within those territorial boundaries to find food, water, shelter, shade, and—sometimes—other rhinos.
Due to persistent hunting, poaching and destruction of rhinoceros habitat, only about 5,000 black rhinos survive in Africa today, making them critically endangered. Much of the poaching is driven by the demand for rhinoceros horn, which is used in traditional Asian medicine and for dagger handles in parts of Africa and the Middle East. Stringent conservation measures, including breeding, anti-poaching efforts, and increased legal protection, strive to preserve the black rhino. But poachers are ruthless in their pursuit of money. In the fall of 2013, they boldly killed a rhinoceros in Lewa Wildlife Conservancy, one of Kenya’s best-guarded parks.