Rhinoceroses (commonly called “rhinos” [RYE-nose]) weigh more than 2,200 pounds (1,000 kilograms) as adults. Their barrel-shaped bodies are supported by short legs that end in three-toed feet. The mobile ears are large, tiny eyes are situated on either side of the head, and the neck and tail are short. Rhino horns are not made of bone, but of keratin (KARE-ah-tin), the same material in hooves, hair, and fingernails. They are not attached to the skull. These horns never stop growing, and they will re-grow should they be knocked out in battle or otherwise.
Skin thickness varies with the species. Rhinos have large sweat glands scattered over the skin that allows them to sweat often and a lot to help keep them cool. Their eyesight is poor, but their sense of hearing is well developed and facilitated by ears that can swivel. Their most acute sense is that of smell. Rhinos vary in coloration from gray to brown.
Found in Africa and Southeast Asia.
Different species prefer different habitats. The white rhino likes grasslands and savannas (similar to grasslands but with small trees and bushes), while the black rhino prefers bushland and semidesert. The Indian rhino is found on meadows and swamplands, and Sumatran and Javan rhinos occupy rainforests.
Rhinos are vegetarians and feed primarily on leaves, fruit, grasses, and stems. They have one stomach, which could lead to poor digestion. Because of their large size, however, rhinos have longer periods of digestion, making it more efficient. Rhinos need water not only for drinking, but for wallowing in as well.
BEHAVIOR AND REPRODUCTION
Rhinos are solitary (lone) animals, but are primarily found in the mother-offspring pair. Their poor eyesight prohibits them from clearly seeing anything farther away than 100 feet (30 meters). Their sense of smell alerts them to danger. Rhinos are normally gentle creatures and they will only charge an intruder if they feel threatened.
Courtship behavior (mating rituals) of the rhino is so aggressive that it sometimes ends in injury to one or both parties. Rhino males are territorial and will fight with other males to defend territory or to mate with females. Rhinos do not form bonds and the sexes do not associate with each other outside of mating.
Pregnancy lasts fifteen to sixteen months and results in a single birth. Rhino calves remain with their mothers for two to four years, at which time they live independently. Baby rhinos nurse (drink mother’s milk) for one year, but begin supplementing with vegetation at one to two months. Rhinos are ready to mate between the ages of four to five years, but males often wait until the age of ten due to competition from other males. Babies are born every two to five years. Rhinos can live to be forty years old and have no natural predators.
RHINOCEROSES AND PEOPLE
Humans have long been fascinated with the rhinoceros, as indicated in cave art from the Early Stone Age. Unfortunately, this fascination hasn’t kept humans from reducing all rhino populations. Rhinos are especially valued for their horns, which are used to make dagger handles in Yemen (believed to give the owners invincibility) as well as medicine in China and India. Because the horn is made of keratin, the same as hair and fingernails, the there’s no evidence to support the claim that it holds medicinal power.
The only species that isn’t threatened is the white rhino, though it once was in serious jeopardy. Today, the Javan, Sumatran, and black rhinos are Critically Endangered, facing an extremely high risk of extinction, while the Indian rhino is considered Endangered, facing a very high risk of extinction. Poaching (illegal hunting) is to blame for the threat to all rhinos.