White rhinoceros cow with calf. ©Getty Images

White rhinoceros cow with calf. ©Getty Images

Rhinoceros, or rhinos, are mammals with horns on their noses, either one or two. Their name comes from Greek words rhino, meaning nose, and ceros, meaning horn.

Rhinoceros horn is made from keratin, the same substance as our hair and fingernails. The horn is stiff, matted fibres, compressed so that it is hard. Rhinos can sharpen their horns by rubbing them on rocks and trees.  

The closest living relative to the rhinoceros is the horse.

Five species

There are five species, or kinds, of rhinoceros: two live in Africa (black rhino and white rhino) and three are found in Asia (Javan, Sumatran and Indian). 

Female rhinos are called cows, males are bulls and young are calves.

A rhino's body

Rhino skin ©Getty Images

Rhino skin ©Getty Images

All rhinos have thick skin. They are herbivores and have to eat a lot because of the way they digest their food: the food is broken down in the part of the gut that is past the part that takes out nutrition for the body.  So they have to spend most of the day eating in order to get enough nutrition for their huge bodies. 

Rhinoceros have three toes on each foot, with a soft pad in the middle of the foot which helps to carry their enormous weight. They are very strong and powerful animals.

Rhinoceros have poor eyesight, but make up for it by having excellent senses of smell and hearing. Because they have little hair on their bodies, rhinoceros dig up mud with their horns, then roll in the mud to to keep cool, to keep their skin in good condition, and to keep insects from biting. 

The biggest rhinoceros species

White rhino calf just weeks old. The horn is beginning to grow. See the square lip. ©kidcyber

White rhino calf just weeks old. The horn is beginning to grow. See the square lip. ©kidcyber

The two African species, the white rhinoceros and the black rhinoceros, both have two horns. Their horns grow very long, some reaching 2 metres in length. The front, or primary, horns are the longer. Groups of black rhinos and white rhinos are found in different areas of Africa and are sometimes identified by the area, for example, there are northern and southern white rhinos. However, these are geographical details and the differences between these groups is not big. The white rhinoceros isn't actually white, nor is the black rhino actually black.  Both are greyish brown, although they can look brown when covered in dried mud.

White, or square-lipped, rhinoceros. ©kidcyber

White, or square-lipped, rhinoceros. ©kidcyber

Both the black and white rhinoceros have a large head, broad chest and thick legs.

Life cycle

Females are pregnant for about 18 months before giving birth to a single calf,  which does not have a horn when it is first born. The horn starts to grow soon after birth.  Rhinoceros calves are able to walk and run about an hour after birth. When there is danger, they run in front of their mothers for safety. They suckle milk from their mothers. They stay with their mothers for 2 or more years.

White rhinoceros

The white rhinoceros is the largest of all five rhinoceros species - about 1.7 metres tall and up to three and a half tonnes in weight. It is considered to be the second largest land animal after the elephant.  It has a longer and heavier head than the other species. The head alone can weigh almost 1,000 kilos, so the white rhinoceros has a hump on its shoulder containing a mass of muscles just to support and move the head.

Its mouth is wide and straight because it is a grass eater and the mouth shape makes it easier to walk along and graze.  It is often called 'square-lipped rhino' which is a more accurate term than white rhino.

Black rhinoceros. ©Getty Images

Black rhinoceros. ©Getty Images

Black rhinoceros

The black rhinoceros is smaller than the white rhinoceros. It is a browser, which means it eats leaves of trees and shrubs.

To help it do this, it has a a pointy upper lip that works rather like a finger, grabbing leaves and shoving them into the mouth. They are also known as hook-lipped rhinoceros.

Black, or hook-lipped, rhinoceros. ©Getty Images

Black, or hook-lipped, rhinoceros. ©Getty Images

Indian rhinoceros ©Getty Images

Indian rhinoceros ©Getty Images

Indian rhinoceros

The Indian rhinoceros is the largest of the three kinds of Asian rhinos, second in size to the African white rhinoceros because although it can be taller than the white rhino, it is not as heavy. It is about 1.7 metres tall and about 3.5 m long, weighing up about 2,500 kg.  It has one horn, about 30 centimetres long. It has bumpy skin that has big folds and bumps so that it looks like it is covered in armour plates.

The Indian rhinoceros is found in grasslands on flood plains of rivers, and sometimes in nearby woodlands, in Bhutan, northern India and southern Nepal. They eat grass, fruit, leaves and even crops. They have a special upper lip that helps them grab plants, particularly tall grasses, and helps them pull them up water plants by the roots. They feed in early morning or late afternoon and not in the hottest part of the day. 

About 16 months after mating with a male, a female  gives birth to one calf, usually between the end of February and the end of April. Usually females give birth every 2-4 years. The calves drink milk from their mother until they are about 2 years old, but they gradually eat more solid food during this time. Indian Rhinos live for about 45 years.  

The smallest rhinoceros species

The other two rhinoceros species are found in Indonesia. They are named after the islands on which they are mostly found: Sumatra and Java. The Javan and Sumatran Rhinoceroses live in wooded areas, in thick rainforests where they are hard to see. They are smaller than the other kinds of rhinoceros to make it easier to move in the rainforest. Both species can swim, and generally live in places where there is good water supply. Both species are solitary (live alone), except at breeding time. They wallow in mud to keep cool and for protection from the sun and biting insects.

Both species are browsers, which means they feed on the shoots, twigs, leaves and fruit of trees and bushes. They also eat the fallen fruit of certain plants. Both use their jaws and chest to bend trees so they can feed from branches at the top. They have a pointy upper lip to help them feed from bushes and trees by grabbing leaves and pushing them into the mouth.   About 16 months after mating, a female  gives birth to one calf, which she protects fiercely, charging at enemies and attacking with her sharp front teeth and horn. Young stay with their mothers for about 2 years.

Javan rhinoceros ©Getty Images

Javan rhinoceros ©Getty Images

Javan rhinoceros

The Javan rhinoceros is the rarest of the five species: there are only about 60 left in the wild. The skin of the Javan rhinoceros forms heavy folds, and looks a bit like armour. Males have one horn, about 25cm long, and females have a small horn or none at all. The Javan rhino is about 165 cm tall and weighs about 900-2,000 kilos. It often lies in streams, where small fish and crabs feed on the insects that live on its skin. It can go for several days without drinking, and may travel great distances to find water if necessary.

Sumatran rhinoceros ©Getty Images

Sumatran rhinoceros ©Getty Images

Sumatran rhinoceros

The Sumatran Rhinoceros is the smallest of the five species of rhinoceros, at 135 cm in height and about 1,000 kilograms in weight. They are now considered to be extinct in the wild in Malaysia. There are now just three small groups, all in Indonesia. The Sumatran rhino has two horns and is the only one of the five species that has fur – it has a coat of shaggy hair. It is able to swim across wide rivers with ease. It is extremely shy and difficult to observe.

Rhino horn: see the keratin fibres near the base. ©kidcyber

Rhino horn: see the keratin fibres near the base. ©kidcyber

Conservation status and threats

Rhinoceros species are endangered partly because their habitat is destroyed by humans, but mainly because they are hunted and killed for their horns alone.  Some people believe that dried, ground rhinoceros horn has magical medicinal powers to cure fever and other ailments. Modern pharmacy can do this more cheaply and without making an animal species endangered. In some countries, the horn is carved and polished and made into special ceremonial dagger handles.

Poachers are a danger

In some places where rhinoceros lived, they are now gone. Although it is illegal to kill rhinoceros, poachers still kill them, and rhino horn still fetches a high price. Although a rhino's horn does grow back, poachers kill the animal and saw off the horn.

  • White rhinoceros were once thought to be extinct, but numbers have increased in protected areas and are now classified as Near Threatened, with about 20,000. 
  • The black rhinoceros is classified as Critically Endangered, with about 5,000 left in the wild. 
  • The Indian rhino is classified as Vulnerable.  
  • Javan rhinos are classified as Critically Endangered, with probably only about 50-60 left in the wild.
  • Sumatran rhinos are classified as Critically Endangered, with about 100 left in the wild. Action is being taken to move the three remaining groups to one location, In Way Kambas National Park in Indonesia, with an increased protection zone. Captive breeding efforts are to increase, and those rhinos to be moved to join the remaining wild group.
Indian rhinoceros calf ©Getty Images

Indian rhinoceros calf ©Getty Images


Watch a video about wild white rhinoceros in Botswana here

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