Over the last decade or so, terrible reports concerning rhino poaching have been spread across the media, and all people except for those living on the moon are familiar with the poaching pressures which this unique species currently faces. Despite all the negative media coverage and emotional draw strings attached to their plight, how much do you actually know about them as a species?
These prehistoric pachyderms have been wondering the Planet for approximately 50 million years in comparison to the meagre 30 000 years that modern man (Homo erectus) has been around. This long evolutionary path, coupled with anthropogenic factors has resulted in five different ‘modern’ rhino species roaming the earth today – all exclusively restricted to conservation areas and zoos. A brief description (in a bid to avoid providing too much detail, for obvious reasons) of each species follows below:
• Black Rhino (Diceros bicornis)
There are five subspecies of black rhino, which occur in southern, central and east Africa. Their preferred habitat is tropical bush lands, grasslands and savannahs in Africa. The average adult weight achieved by both male and female individuals is between 800 – 1 350 kg. Black rhino are strictly browsers and use their prehensile lip to strip off leaves, flowers, shoots and twigs. Adult individuals have two horns which are quite variable in shape and length, with the front horn reaching up to 132 cm in length.
The name black rhino does not relate to the colour of the animal, and it probably derives its name from the dark coloured local soil covering its skin from wallowing. Diceros was formerly the most widespread and numerous rhino species, and a notably successful member of the herbivore community. There are currently around 4 860 surviving individuals left in the world.
• White Rhino (Ceratotherium simum)
White rhino are divided into two distinct subspecies: The northern white rhino (C.s. cottoni) and the southern white rhino (C. simum). The southern white rhino is the least endangered of the living species of rhino. Unfortunately, the northern white rhino is feared extinct in the wild, as reported on June 17, 2008. There are only eight known northern white rhino left in the world.
The white rhino, like its smaller cousin occurs in southern and central Africa. They favour a different habitat to the black rhino and are generally found in long and short grass savannahs in Africa. The average adult weight achieved by both male and female individuals is between 1 800 – 2 700 kg. This makes the white rhino the biggest land mammal after the elephant (although outweighed by the hippo). White rhino are strictly bulk grazers and prefer to feed on lower stratum grasses. Adult individuals have two horns, with the average length being 60 cm and the maximum length being around 150 cm.
The white rhino is actually not white in colour; the name is thought to be a result of mistaking the Dutch word ‘wijd’ (meaning ‘wide’, pertaining to the wide lip) for ‘white.’ White rhino are grey, although they often look brown due to being covered in mud after wallowing. There are currently around 20 000 surviving individuals left in the world.
Moving off of the African continent, there are another three species remaining throughout the world, namely the:
• Indian Rhino (Rhinoceros unicornis)
The Indian rhino, a.k.a. greater one-horned rhino, or Nepalese rhino is found in northern India and southern Nepal. This species favours floodplains and riverine grasslands. The Indian rhino is very similar in size to the white rhino, as they too reach weights of 1 800 – 2 700 kg. Indian rhino are mixed feeders, feeding on a spectrum of vegetation, ranging from grass, fruit, leaves, shrubs and branches. As the species name ‘unicornis’ suggests, the Indian rhino has one horn, which on average grows to a length of 20 – 60 cm.
The Indian rhino is greyish, and the skin forms distinctive folds around the body, making the rhino appear to be wearing plates of armour. They are the most aquatic of the five rhino species. They are strong swimmers and may spend 60% of their day in the water. Indian rhino can dive and feed under water, and it is not uncommon to see just their snouts, eyes, and ears above the water. There are currently around 2 940 surviving individuals left in the world.
• Sumatran Rhino (Dicerorhinus sumatrensis)
The Sumatran rhino, a.k.a. hairy is found in south-east Asia, primarily in Indonesia and Malaysia. Owing to its small body size, this species favours tropical rainforests and mountain moss forests. The Sumatran rhino is the smallest of all the rhino species, standing only 90 – 150 cm high at the shoulder. The adults reach a weight of 600 – 800 Kg. Sumatran rhino are generally browsers and will feed on fruit, leaves, twigs and bark. This species has two horns, with the average front horn length between 25 – 80 cm. The second horn is quite small and usually measures around 8 cm.
By far the Sumatran rhino’s most distinguishing feature is the hair. The Sumatran rhino’s reddish brown skin is covered with coarse hair, which grows quite long and shabby but gets worn down a little from rubbing against rough objects. There are currently less than 200 surviving individuals left in the world.
• Javan Rhino (Rhinoceros sondaicus)
With fewer than 50 Javan rhinos surviving in only one known location, the Javan rhino is quite possibly the most critically endangered mammal on earth…
There are none in captivity, and the remaining numbers can only be found in the Ujung Kulon National Park in Indonesia, where as mentioned above, the population appears to have fewer than 50 rhino. The Vietnamese subspecies of the Javan rhino was declared extinct in 2011. The species favours lowland tropical rainforests. The adults reach a weight of between 900 – 1 400 kg. Interestingly, Javan rhino are mixed feeders, although they do predominantly browse but will frequently graze. One of the most notable features of this species is its large prehensile upper lip. This species has one horn, which grows to about 25 cm in length, and is thought to occur only in the male Javan rhino.
The Javan rhino is grey or greyish brown, and the skin has a mosaic patterning that gives it a somewhat prehistoric appearance. Like the Indian rhino, these rhinos have distinctive folds of skin on its body, which look like plates of armour. A large part of the Javan rhino’s day is spent in the water, wallowing in mud holes, pools, and puddles. As mentioned above there are fewer than 50 living individuals left in the world.
After briefly delving into the remaining rhino biodiversity left, let’s take some time and celebrate the five species of rhino on World Rhino Day on the 22 September.