There are five species of rhino: white rhino (Ceratotherium simum), black rhino (Diceros bicornis), Greater one-horned rhino (Rhinoceros unicornus), Sumatran rhino (Dicerorhinus sumatrensis), Javan rhino (Rhinoceros sondaicus)
Why are rhinos important?
Rhinos are a keystone species, meaning they play a vitally important role in shaping and maintain their ecosystem. By wallowing in mud and water, rhinos help create natural waterholes which other animals can utilise. They also eat a lot of plants and then recycle nutrients in their ecosystem through their dung and urine. Their dung is an important habitat for numerous invertebrates, which, in turn, helps boost the populations of small birds and mammals who feed on insects.
Their feeding behaviour helps maintain savannah habitats and boosts the diversity of rainforests by creating openings in the canopy, allowing for new growth. Because rhinos have relatively large ranges, by protecting them and their habitat, it is possible to safeguard large numbers of other species.
Black rhino, Javan rhino, Sumatran rhino: Critically Endangered / white rhino: Near Threatened / Indian rhino: Vulnerable
Black rhino: ~5,630 (3,142 mature individuals), increasing / Javan rhino: ~68 (~18 mature individuals), stable ️ / Sumatran rhino: ~80 (~30 mature individuals), decreasing / White rhino: ~18,064 (~10,080 mature individuals), decreasing️ / Indian rhino: ~3,588 (~2,100-2,200 mature individuals), increasing️
Black rhino – 2020; Javan rhino – 2019; Sumatran rhino – 2019; White rhino – 2020; Indian rhino – 2018
Grassland plains, savannah, woodland, in true tropical forests and in swamps
Black and white rhino are only found in Africa. Indian, Sumatran and Javan rhino are found in Asia
Weight – 600-2,700 kg, body length – 2-3.8m, shoulder height – 1-2m
Poaching, habitat loss, disease
Did you know?!
In Africa, an oxpecker bird can often be found hitching a ride with a white or black rhino. They have a mutually beneficial relationship. The oxpecker eats the insects and ticks that live on rhinos, while the rhinos, who have poor eyesight, can be alerted to danger – specifically humans – by the oxpecker. In Swahili, the oxpecker is known as the ‘Askari wa kifaru’, literally meaning the rhino’s guard.
How to recognise a rhino
Rhinoceros belong to a group known as the perissodactyls, or odd-toed ungulates, which includes horses and tapirs. All species can weigh more than a tonne and have one or two horns.
Each rhino species has a slightly different appearance. Black and white rhinos are both actually grey but can be distinguished by their different lip types adapted due to their specific diets.
Black rhinos are browsers, feeding from bushes and trees rather than ground vegetation – they have a pointed or hook like lip to help them do this. The white rhino is a grazer with a square lip, adapted to eating grasses. The Sumatran rhino is unique as it has shaggy hair on its ears and body and is the only two horned rhino in Asia. Javan rhinos are recognisable by their skin folds which look like plated amour.
Most rhino species lead largely solitary lives although they will sometimes share feeding grounds, water holes and wallows. The closest relationship is between a mother and her calf, who stay together between two and four years. As calves mature they leave their mothers and may join other females and their young temporarily, before living completely on their own. Males are territorial to varying extents, often marking their territory with dung.
Rhino feeding behaviour is different between species. While white rhinos are known as ‘grazers’ who prefer grasses, the black rhino is a ‘browser’ and consumes branches, leaves, twigs and hanging fruits. In the tropical forests of Indonesia, Javan and Sumatran rhinos are also browsers, eating a wide diversity of plant species on offer.
Rhinos, especially black rhinos, can appear rather ill-tempered – particularly in areas where they are hunted or regularly disturbed. They have poor eyesight, which might explain why they sometimes charge without apparent reason. They have an extended vocabulary of growls, grunts, squeaks, snorts and bellows.
Wild rhinos have a lifespan of 30-50 years. Pregnancy lasts 15-16 months and the 63kg newborn calf relies on its mother’s milk for up to two years.
Where do rhinos live?
African rhinos, which includes the white rhino and the black rhino, are found in savannahs, forests and shrub habitats. The greater one-horned rhino lives in the grasslands, swamps and forests of India and Nepal. The Javan rhino is found in lowland tropical rainforest close to water sources. The Sumatran rhino, which also lives in Indonesia, inhabits tropical rainforests and mountain forests.
Illegal hunting for sport and the poaching of the animals for their horns, used in traditional Asian medicine, had led to a dramatic fall in rhino numbers. Poaching, combined with civil wars, has devastated the population of northern white rhino, leading to functional extinction, meaning there is no longer a viable population. Only two female northern white rhinos are known to survive in the world and the last male died in 2018.
Rhino habitats are encroached on by human population growth, agricultural development and domestic livestock. They are slow and sensitive breeders and when their land is severely fragmented populations become smaller and more isolated, making it even more difficult for them to reproduce. Non-native species are also reducing the quality of habitat, particularly for the greater one-horned, Sumatran and the Javan rhinos. These species are already at incredibly at risk because their populations occur in only one or a few sites.
Due to the small populations of greater one-horned rhinos, Javan rhinos and Sumatran rhinos the risk of inbreeding is high.
Infectious diseases transmitted by livestock encroaching into protected areas presents a risk to small populations such as the Javan and Sumatran rhino.