Top 10 facts about rhinos

1. There are five rhino species around the world

There are five recognized species of rhinoceros. Two of them are native to Africa: the black rhino and the white rhino. The other three are found in Asia and include the greater one-horned rhino, Sumatran rhino and Javan rhino.

The Sumatran, Javan and black rhinos are all classified as critically endangered by the IUCN. Fewer than 70 Javan rhinos are believed to remain in the wild, while the estimated number of Sumatran rhinos is only around 34 to 47. The black rhino population is estimated at approximately 6,487 animals across Africa.

White rhinos are currently considered near threatened, with an estimated population of 16,803. The greater one-horned rhino is classified as vulnerable, with about 4,014 individuals remaining in the wild.

2. Rhinos can weigh more than three tonnes

Although the Sumatran rhino is the smallest of the five species, it can still reach around 600 kilograms in weight, which is close to 95 stone.

At the opposite end of the scale, the white rhino is the largest species. Some individuals can weigh as much as 3,500 kilograms, or more than 550 stone. That means these enormous animals can exceed three tonnes despite having a diet consisting mainly of grass and leaves.

3. Black and white rhinos are actually both grey

The names black rhino and white rhino can be confusing because neither species is truly black or white. Both animals are generally grey in colour.

The name “white rhino” is thought to have originated from the Afrikaans word “wyd,” meaning wide. This refers to the animal’s broad, square-shaped upper lip, which differs from the pointed upper lip of the black rhino.

Early English explorers apparently misunderstood the word and interpreted it as “white.” The other species subsequently became known as the black rhino to distinguish it from the white rhino.

4. Male rhinos are bulls and females are cows

Adult male rhinos are known as bulls, while females are called cows. Their offspring are referred to as calves.

Female rhinos are generally more social than males, which tend to be solitary and strongly territorial. A group of rhinos is traditionally called a “crash.”

5. Rhino horns are made from the same protein found in our hair and nails

Rhino horns consist primarily of keratin, the same protein that makes up human hair and fingernails.

Javan rhinos and greater one-horned rhinos have a single horn, while the other three rhino species possess two horns. Rhino horns continue growing throughout the animal’s lifetime. A white rhino horn can increase in length by approximately 7 centimetres each year, and the longest recorded horn has reached around 150 centimetres.

6. Rhinos do not have very good eyesight

Rhinoceros eyesight is relatively poor. For example, a rhino may have difficulty detecting a person who remains completely still at a distance of around 30 metres.

Because their vision is limited, rhinos depend heavily on their highly developed sense of smell to understand what is happening around them and detect potential threats.

7. Javan rhinos now survive in only one small area

The last remaining wild Javan rhinos are found in Ujung Kulon National Park, a World Heritage Site in Indonesia.

However, this isolated population faces serious environmental risks. An active volcano is located only about 50 kilometres away, while scientists have warned that a tsunami reaching up to 10 metres in height could occur within the next century. Such an event could potentially affect as much as 80% of the rhinos’ habitat in Ujung Kulon National Park.

For this reason, creating a secure second population of Javan rhinos elsewhere in Indonesia has become an important conservation goal.

8. Rhinos communicate with sounds, smells and even dung

Rhinos use a surprisingly wide range of sounds to communicate with one another.

During confrontations, they may growl or produce loud trumpet-like calls. Black rhinos can snort when irritated, make sneeze-like sounds to signal an alarm, scream when frightened and produce a sound described as “mmwonk” when they are relaxed.

Communication is not limited to vocalizations. Rhinos also use urine and dung to exchange information. They often defecate in shared areas known as latrines. By detecting the scents left behind by other rhinos, individuals can determine which animals have recently been in the area.

9. Rhinos enjoy covering themselves in mud

Rhinos are often seen wallowing in mud. Covering their bodies with mud creates a natural protective layer that helps them remain cool, reduces insect bites and removes or discourages parasites.

Asian rhino species are also capable swimmers and can cross rivers relatively easily. African rhinos, however, are much less capable in deep water and may even drown. Instead, they rely heavily on mud wallows to cool their bodies and protect their skin.

10. Rhinos continue to face serious threats

The modern rhino poaching crisis began escalating significantly around 2008. Illegal killings across Africa reached a peak of 1,349 rhinos in 2015.

Although intensive conservation programs have helped reduce poaching levels, the problem remains extremely serious. In 2022, 448 rhinos were illegally killed across Africa, equivalent to more than one rhino every day.

Poaching operations have also become increasingly sophisticated. In some cases, helicopters are used to locate animals. After rhinos are shot with firearms or immobilized with tranquilizing darts, their horns are removed with chainsaws and transported away by air.

Ground rhino horn has been used in some forms of traditional Asian medicine to supposedly treat conditions ranging from cancer to hangovers, even though there is no scientific evidence that it provides medicinal benefits. More recently, rhino horn has also been associated with social status, particularly in Vietnam.

Poaching is not the only danger facing these animals. Habitat destruction and the fragmentation of remaining populations are becoming increasingly important concerns as human settlements, roads and other infrastructure expand into rhino habitat. Climate change adds another challenge, with droughts, floods and other extreme weather events capable of placing additional pressure on already vulnerable populations.