RHINOCEROSES: RhinocerotidaeSUMATRAN RHINOCEROS (Dicerorhinus sumatrensis): SPECIES ACCOUNTS
INDIAN RHINOCEROS (Rhinoceros unicornis): SPECIES ACCOUNTS
WHITE RHINOCEROS (Ceratotherium simum): SPECIES ACCOUNTS
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.
HUMAN GREED SPELLS DEATH FOR BLACK RHINOS
For nearly twenty years, the African Wildlife Foundation has been committed to rhinoceros conservation. Much of its funding supports black rhino protection and conservation in the Tsavo East National Park in Kenya.
In the 1970s, the black rhino population was between six and eight thousand. By 1989, however, the population had dwindled to twenty. Poaching is the sole reason for the decline of the rhino population throughout Africa. As a way to counterbalance this tragic pattern, Tsavo East created the Ngulia Rhino Sanctuary (NRS) in 1985. It began with three rhinos in a fenced-in area less than 1 square mile (less than 1 square kilometer). Today it is larger than 38 square miles (98 square kilometers) and is home to fifty-seven rhinos, half of whom were born in the sanctuary.
Although the numbers are slowly rising, it isn't happening without a cost. In May 2003 two park rangers were murdered in an effort to protect the rhinos from poachers. Poaching continues throughout rhino ranges, but sanctuaries like NRS are key to bolstering the rhino population.
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.
Physical characteristics: This is the smallest and oldest living rhino species, with a weight from 2,200 to 4,400 pounds (999 to 1,998 kilograms) and a shoulder height of 48 to 58 inches (120 to 150 centimeters). From head to tail, this species measures 100 to 125 inches (250 to 315 centimeters). The body is covered sparingly with short hairs, and the hide is dark red-brown. The horn closest to the snout can measure up to 31 inches (79 centimeters), but that is unusually long, and it is normally much shorter. The other horn is no longer than 6 inches (15 centimeters). Both sexes have horns.
Geographic range: Though they once roamed over Southeast Asia, they are found only on the island of Sumatra and in the Malay peninsula today.
Habitat: The Sumatran rhino lives in mountainous rainforests today, but experts believe it may have once occupied lowland forests, as well. They need to live near permanent bodies of water.
Diet: This species eats mostly twigs and leaves of small trees and shrubs. It also enjoys fruits and herbs. Although these rhinos feed on undergrowth along streams, they will reach higher shoots and twigs by walking on plants and pressing down on the trunk of saplings with their round bodies.
Behavior and reproduction: Sumatran rhinos are solitary and come together only to breed, although calves and mothers are frequently seen together. They like to wallow in mud holes, which not only keep them cool, but also protect their thin outer layer of skin from insect bites and thorns. Males roam whereas females have home ranges covering 4 to 6 square miles (10 to 15 square kilometers). Each territory has a salt lick, which the rhinos visit frequently.
Pregnancy lasts 475 days and calves weigh around 72.8 pounds (33 kilograms). While nursing, females confine their movements to small areas close to a salt lick. Calves leave their mothers between sixteen and seventeen months, at which time the mother returns to her non-breeding range. Females give birth about every four years.
Sumatran rhinoceroses and people: The number of Sumatran rhinos has decreased by 50 percent in the past twelve years due to poaching. It is believed that as of 2002, there are fewer than three hundred left in existence. Captive breeding has not been successful, as it has come to light that rhinos have strange mating habits that captivity cannot allow.
Conservation status: Listed as Critically Endangered since 1996. ∎
Physical characteristics: This species has skin that is covered in what looks like plates of armor. Indian rhinos also have just one horn. Males can weigh up to 4,600 pounds (2,100 kilograms), while females weigh around 3,500 pounds (1,600 kilograms). Males measure to 150 inches (380 centimeters) in length, females to 135 inches (340 centimeters). Both sexes have the horn, which measures around 18 inches (45 centimeters). The hairless skin is gray and has flat bumps on it.
Geographic range: Indian rhinos are found in Pakistan, India, Nepal, and Bangladesh.
Habitat: The Indian rhino lives on floodplains and swamplands with tall grasses as well as adjoining woodlands on drier ground.
Diet: This species uses its upper lip to grasp grass stems and bushes. The lip folds back when the rhino wants to graze. The tall grasses of
the preferred region supply food year-round. During winter, woody vegetation is important. The Indian rhino also eats aquatic plants and green fallen fruits. These rhinos will step on plants and pull down stems so they can bite off the tips of vegetation. In doing so, they disperse seeds, thus guaranteeing a plentiful food supply.
Behavior and reproduction: Solitary like other rhinos, the Indian rhino gathers around and wallows in bathing pools, as well as in feeding areas. Males are aggressive and fights break out when strange rhinos trespass on others' territory. This species is very vocal. Indian rhinos spend more than half of their time feeding.
After a courtship that includes the male chasing the female, sometimes for more than a mile (1.6 kilometers), the pair begins horn fighting. This can lead to biting, and it is common for them to inflict open wounds during mating. Pregnancy lasts sixteen months at which time the female gives birth in a secluded forest area or dense grassland region. Calves weigh 140 to 150 pounds (65 to 70 kilograms) and nurse until they are two years old. They leave their mothers a week or two before the birth of the next offspring, though females may remain on the maternal home range. Females give birth every three-and-a-half to four years. Indian rhinos can live up to thirty years in the wild with tigers as the only natural predator of the young.
Indian rhinoceroses and people: Tourists ride on elephants' backs to view Indian rhinos in some sanctuaries. Local people aren't as fond of the animals, as the rhinos tend to eat crops at night. In some instances, Indian rhinos have killed humans.
Conservation status: Indian rhinos are listed as Endangered by the IUCN due to poaching and competition from cattle and agricultural development. ∎
Physical characteristics: This is the largest rhino species. Males can weigh up to 5,000 pounds (2,300 kilograms), while females weigh around 3,800 pounds (1,700 kilograms). Males measure to 150 inches (380 centimeters) in length, females to 135 inches (343 centimeters). The body is covered sparingly with short hairs, and the hide is gray. The horn closest to the snout measures 20 to 62 inches (50 to 158 centimeters. The other horn is no longer than 15 inches (40 centimeters). Both sexes have horns.
Geographic range: In the nineteenth century, the white rhino was found in two separate regions of Africa: southern Chad, Central African Republic, southwest Sudan, northeast Democratic Republic of the Congo, and northwest Uganda; and southeast Angola, parts of
Mozambique, Botswana, Zimbabwe, Namibia, and northeast South Africa. Today the white rhino occupies fragments of these areas and is restricted to game preservations and national parks.
Habitat: The white rhinoceros prefers the drier savanna regions in southern Africa, yet prefers the moist savanna in the northern range.
Diet: The southern white rhino eats grasses and also ingests herbs and occasionally woody shrubs. Short grasses are the preferred food year-round, though later in the dry season, interest turns to some of the taller grasses. The northern rhino prefers short grasses but includes medium-tall grasses in its foraging.
Behavior and reproduction: White rhinos seem to be the most complex species of the family. Their range varies in size from less than 1 square mile (less than 1 square kilometer) to 5 square miles (8 square kilometers). They spend their entire lives within these ranges, and live in small groups with one dominant male, numerous females and their offspring, and even some sub-adult males. Fighting is rare. Lions have been reported to prey on young calves, but that is the extent of natural predators.
Gestation lasts sixteen months, at which time the female seeks a quiet place to birth her single calf. Calves nurse until the age of fifteen to twenty-four months, though they begin eating vegetation after a couple months of age. Females are sexually mature between the ages of six and eight years while males begin breeding around ten to twelve years. White rhinos live no longer than about forty years in the wild.
White rhinoceroses and people: White rhinos are terrified of humans. Early European hunters brought the white rhino to near extinction as they harvested populations for their meat and other body parts. The southern population has recovered well, but the future of the northern species is questionable at best.
Conservation status: The white rhino is listed as Near Threatened by the IUCN because even though population levels are higher than other rhino species, this breed is easy to track down and hunt, so reintroduced herds have been easily eliminated. The horn of the white rhino is particularly valuable, fetching a couple thousand dollars per horn on the black market. Recently, a herd of young male elephants killed a number of white rhinos. This is normally highly unlikely, but these particular elephants were orphaned at a young age and had no older bulls in the herd. Once older bulls were introduced, the aggression of the younger elephants subsided, demonstrating the importance of hierarchy in elephant populations. ∎
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Toon, Steve, Colin Baxter, and Ann Toon. Rhinos: Natural History and Conservation (WII). Stillwater, MN: Voyageur Press, 2002.
Mill, Frances. "A Horse is a Horse, Of Course—A Rhinoceros is a Horse." Boys' Life (February-March, 2004).
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