The Mighty Rhinoceros: Exploring Rhino Diversity

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It’s believed that rhinos have been around for more than 50 million years, and these prehistoric-looking creatures are some of the most robust on the planet. While there are several species of rhinoceros, many are endangered, and it would be devastating to say goodbye to such an incredible animal.

Rhinoceros Overview

The rhinoceros is a species of mammal that belongs to the Rhinocerotidae family. These are herbivorous animals that feed on shoots, leaves, grasses, and fruits, whose name comes from the Greek language with rhino meaning nose and ceros meaning horn. It’s their horns for which they are most well-known.

Because of their diet, rhinos are an important part of their ecosystems as they disperse seeds and help to control the ecological balance through grazing. They don’t have particularly good eyesight and largely navigate the world using their excellent sense of smell. Plus, despite feeding on a plant-based diet, these huge animals can weigh more than 6,000 lbs (3 tons)!

Male rhinos are called bulls, while the females are called cows, and while they’re not classed as bovines, they are part of the same group of odd-toed ungulates. Altogether, there are five species of rhinoceros, which I will discuss in more detail later in this article.

The rhinoceros is generally a solitary animal unless they need to defend their territory, which is usually the case for mothers and their calves. These animals can live for up to 50 years in the wild, and males and females reach sexual maturity between the ages of 7 and 10 or 4 and 6, respectively. Once pregnant, the female rhino will carry her calf between 420 and 570 days.

As I mentioned in the introduction to this article, rhinos have been around for tens of millions of years. What’s more, there are ancient fossils of wooly rhinoceroses that date back as far as 3.7 million years.

Today, rhinoceroses face many threats, with one of the main being targets of poaching, which often happens illegally as it has been outlawed in most countries. The problem is that many nations see rhinos as a cultural symbol and prize their horns for use in traditional medicine and because owning them is something of a status symbol.

In some cultures, it is reported that the rhino horn is used as an aphrodisiac but this is largely something that has been misinterpreted by the Western world. What’s more, despite the alleged use in medicine, rhino horns are made from the same stuff as your hair and fingernails, so serve no useful medical purpose.

However, these are not the only threats to rhino populations and they’re also victims of the illegal wildlife trade and habitat loss.

Rhinoceros Adaptations

In order to survive in their natural environment, rhinoceroses have a number of adaptations. These help them when it comes to self-defense, finding food, and much more.

Horns

If there’s one thing that people associate with rhinos, it’s their horns, which are made from keratin which is also found in your nails and hair. Different species of rhinoceroses have different numbers of horns, with one or two being the most common.

So, what are the horns used for? Well, their primary use is for fighting and this may be because of having to defend their territory against other rhinos or for protection from predators. That might sound strange to consider that these large animals even have any predators, but big cats, crocodiles, and hyenas will all give it a go. 

You’ll probably have noticed that rhino horns aren’t overly long, but there is evidence to suggest that their length may have gotten shorter over the years. In the space of just 150 years, researchers that assessed photos of rhino horns noticed a significant difference in their length. It’s thought that this is a result of poachers hunting individuals with larger horns, leaving those with shorter horns behind to pass on their genes and traits.

Thick Skin

The rhinoceros has incredibly thick skin that acts as a tough protective barrier against predators. What’s more, it’s so robust that it also provides protection against minor injuries, and they’ll even coat themselves in mud to prevent their skin from burning in the sun.

Around the neck and shoulders, you will notice that there are thick folds of skin that act as a sort of armor. This is because predators will usually attack these areas, but these skin folds also help the rhino to regulate its body temperature.

Now, just because their skin is thick, that doesn’t mean it’s not sensitive, and that’s one of the reasons that these mighty animals will use mud to protect it.

Efficient Digestive System

Being herbivores, it’s essential that rhinoceroses have effective digestive systems that allow them to extract important nutrients from the plants they eat.

You may be aware that cows and other plant-eaters have more than one stomach and this is also the case in rhinos. Their multi-chambered stomachs are designed to break down cellulose (a tough and fibrous material in plants). If they couldn’t do this, their bodies would not be able to break the plant matter down and absorb the nutrients.

Prehensile Upper Lip

You’ve probably heard of animals with a prehensile tail, but a prehensile upper lip? Yes, this is one of the many adaptations of the rhinoceros, and it allows it to better grasp vegetation and pluck it from the plants.

However, this isn’t something that’s seen in all rhino species, but rather just the black and Asian rhinos, which have pointed prehensile mouths. What’s more, black rhinos don’t have upper teeth. On the other hand, the white rhino has a square-shaped mouth that allows it to pluck grasses.

Acute Sense of Smell & Hearing

Rhinoceroses don’t have very good vision, but they do have an excellent sense of smell and incredible hearing. This is essential in helping them navigate the world, avoid threats, and find food.

One of the reasons rhinos can hear so well is because they’re able to rotate their ears. The ears are also cup-shaped which allows them to pick up on sound very quickly, even when it’s coming from far away.

The rhino’s nose is equipped with super-sized nostrils that are packed with extremely sensitive nerve endings, allowing them to detect even the faintest scents on the breeze.

Importance of Rhinoceros

The rhinoceros is an incredibly important species and plays a crucial role within its ecosystem. Not only this, but they’re an indicator species which is able to tell us a lot about the conditions of the environment.

Ecological Balance

The rhinoceros is considered to be a keystone species which means that removing it from an ecosystem would have a cascading effect on everything else there. One of their most important roles is maintaining ecological balance because, as grazing herbivores, they shape vegetation which therefore improves the structure of the ecosystem.

What’s more, the rhino often feeds on fruits that contain seeds. In order for these plants to reproduce, these seeds need to be dispersed and this occurs as they pass through the rhinoceros’s digestive system unharmed. When the rhino excretes them, they’re in a new location ready to germinate. Without them, the biodiversity of their ecosystems would suffer.

What’s more, the rhino plays an important part in the food chain being a prey animal for carnivores like big cats and hyenas. This maintains the predator-prey balance within the ecosystem and ensures the survival of many other species.

Habitat Engineering

If you were to remove the rhinoceros from its habitat, then you’d quickly notice some very obvious changes. For starters, this is a species that wallows in order to maintain its temperature. But to do that, the rhino has to create wallows (depressions in the ground filled with water), which can become viable habitats for other species, attracting more animals and therefore improving biodiversity.

What’s more, as they graze and make clearings in the forest, these mighty animals create further habitats as well as trails between them, perfectly shaping the world around them. For example, studies have shown that areas without rhinos have 60-80% less grass cover as they encourage grass growth as they graze. In addition to this, regulating plant growth ensures that no one species becomes dominant, again maintaining a perfect balance.

Earlier, I mentioned that rhinos are seed dispersers as they drop undigested seeds out with their faces. But this isn’t the only way that rhinoceros dung can benefit the environment. When it is passed back to the soil, the nutrients within the dung encourage healthy soil where plants can thrive.

Indicator Species

Not only do rhinoceroses shape and maintain the world around them, but they can also tell humans a lot about what’s going on in the environment, giving us very early warning signs if something is wrong. For this reason, they’re known as an indicator species and can tell us a lot about the quality and viability of their habitat.

Where rhinoceros numbers decline or grow, this tells us that there are either problems with the habitat or that it is diverse and thriving. Where issues arise, these early warnings allow conservationists to take action as quickly as possible. What’s more, where rhino populations are doing well, this is often an indicator that other plants and animals in the area are thriving.

Economic Benefits

Ecotourism is big business, but it’s not possible without a varied number of species and rhinos play an important role in this. In the countries where rhinoceroses live, tourism can create a viable income for what might otherwise be very poor communities.

People from all over the world head to national parks where rhinos live just to catch a glimpse of these wonderful animals in the wild. The maintenance of these parks, along with the running of tours, ensures job security for local people. The wider community also benefits because jobs in hospitality and other related industries are also created. As a direct result of this, more infrastructure needs to be created which can enhance the region, and this brings in more tourism, so it’s a very beneficial cycle.

Areas that benefit from ecotourism may also be eligible for conservation funding, which ensures the survival of rhinos and other vulnerable animals, proving that ecotourism benefits everyone and everything involved. Not to mention the awareness raised by having people visit these sites, allowing them to learn about the threats the rhinoceroses face and what they can do to help.

Types of Rhinoceros

There are five rhinoceros species in the world and some have further subspecies. They’re found in both Asia and Africa and each one has its own unique characteristics.

1. White Rhinoceros (Ceratotherium simum)

The white rhino is the biggest species of rhino on the planet, and males can stand as tall as 5.8 feet (1.8 meters) and weigh up to 5,500 lbs (2,495 kg)! They’re sometimes called square-lipped rhinos because, unlike other species, they do not have a prehensile lip but rather a wide mouth that allows them to bite grass close to the ground. They may also feed on branches and leaves, although these aren’t the primary part of their diet.

White rhinoceroses are found in the southern parts of Africa, including South Africa, Namibia, Eswatini, and Zimbabwe, meaning that their populations sometimes overlap with the black rhino. Although they are incredibly territorial, so disputes are not uncommon.

Out of all the rhino species, the white rhino is the one most likely to form a small group with other individuals. These groups are called crashes and are usually made up of mothers and their calves. During mating season, males may even connect with the crash.

As large grazing herbivores, white rhinos are incredibly important to the ecosystem as they control and shape vegetation, spread seeds, and through this, encourage greater plant diversity. Sadly, their populations are under significant threat from poaching, which has led to them being marked as a near threatened species with around 10,000 individuals left in the wild. 

However, there are many efforts in place to protect this amazing two-horned species that has skin folds as thick as 2 inches (5 cm), offering amazing protection. Since white rhinoceroses are important in terms of ecotourism, the revenue earned from this can support conservation projects as well as providing an income to support local communities.

There are two subspecies of the white rhino; the Northern (Ceratotherium simum cottoni) and Southern (Ceratotherium simum simum) white rhinoceroses. Sadly, the northern white rhino is extinct in the wild, and only one living captive individual remains. Things didn’t look hopeful for the subspecies until scientists were able to freeze and inseminate eggs from the last remaining female, creating five viable potential new northern white rhinos!

It’s thought that the northern and southern white rhinos were once one of the same species but split around 1 million years ago. The northern white rhino is markedly smaller and has shorter legs and a less concave skull. Although to the untrained eye, they look very similar to their southern counterparts.

2. Black Rhinoceros (Diceros bicornis)

The black rhino is probably the second most well-known species in the world, and there are three living subspecies, including the south-central black rhino (Diceros bicornis minor), the eastern black rhino (Diceros bicornis michaeli), and the south-western black rhino (Diceros bicornis bicornis). These subspecies are found through the southern and eastern parts of Africa, including South Africa, Zimbabwe, Kenya, and Tanzania.

Interestingly, the black rhinoceros enjoys a range of territories, including woodlands, deserts, and savannas which are all well suited to its browsing herbivorous diet that consists of woody plants, shrubs, and trees. Like many other species of rhino, they have a prehensile upper lip that helps them to grasp foliage and strip it away.

While it is called the black rhinoceros, this species actually has more of a gray coloration similar to that of the white rhino. The main difference is that this species is much smaller, and the white rhino doesn’t have a prehensile lip. However, just like the white rhinoceros, its black counterpart is equipped with two horns, which usually grow to around 20 inches (50 cm). Although in some individuals, they can be triple this length, although this is rare.

Black rhinos are solitary creatures, and the males can be very territorial. They’ll use their horns to fight when necessary, but hopefully things won’t get this far since they often leave feces and use vocalizations to protect their territory.

Unfortunately, illegal poaching due to a high demand for rhino horns in Asia has led to the serious decline of black rhino populations. This has meant that there are now as few as 3000 individuals in the wild, meaning they are critically endangered.

However, by managing and monitoring these animals along with efforts to prevent poaching, we are seeing numbers rise. For example, in Zimbabwe, the number of wild black rhinos has risen to more than 1000, which has not been recorded for over three decades! In South Africa and Namibia, authorities are permitted up to five rhino trophy hunts per year, and targets must meet specific criteria. This is in the hopes that it will decrease the number of illegal poaching incidents. Personally, I think that this is still five too many.

3. Indian Rhinoceros (Rhinoceros unicornis)

Despite its name, the Indian rhinoceros is not only found in India but also parts of Nepal, where it prefers a grassland habitat as well as those around floodplains. In Asia, this is the largest species of rhino, and it also boasts a huge horn that can measure up to 24 inches (60 cm), giving it the common name of the greater one-horned rhinoceros. This species also has very prominent armor-like skin folds that help with thermoregulation. There are no subspecies of the Indian rhino.

Just like other rhino species, the Indian rhinoceros is a solitary animal that’s serious about protecting its territory. To this end, males will mark out their areas with feces and urine. Despite their solitary nature, it’s not uncommon for females to sometimes form groups with other mothers and their young.

In their grassland habitats, Indian rhinos forage for shoots, leaves, and grasses, which they pluck using their prehensile upper lip. Sadly, the habitat of the Indian rhinoceros has diminished dramatically but there are conservation efforts in place to restore it as well as creating protected areas.

In the wild, it is estimated that there are around 2000 individuals, which doesn’t sound like a lot and means that they are listed as vulnerable. However, you have to consider that at the beginning of the 20th century, as few as 200 Indian rhinos remained, so it’s obvious that conservation efforts are having positive results.

Aside from habitat restoration, conservationists are working hard to prevent illegal poaching. These efforts appear to be working because in 2022, for the first time in almost half a century, there were no reports of Indian rhino poaching.

In India and Nepal, the greater one-horned rhinoceros is a population species for tourists. While we must carefully manage wildlife tourism so as not to disturb these wonderful creatures, it is important that this can continue as it provides important revenue for local communities. What’s more, this revenue, along with education of the public, can help conservation efforts.

4. Javan Rhinoceros (Rhinoceros sondaicus)

When you think of endangered mammals, you might think of the tiger or even the white rhino. But a lot of people aren’t even aware of the existence of the Javan rhinoceros, and this is one of the rarest and most endangered large mammals on the planet. In fact, so few remain that it’s now listed as critically endangered, with an estimated 18 mature adults in the wild. However, in 2023, the birth of two new Javan rhinos was reported. 

One of the reasons that this species’ numbers are so low is the limited range. The Javan rhino can only be found on the Indonesia island of Java, where it inhabits wetlands and rainforests. The males can get very territorial and, like other rhinos, this is a largely solitary species. But the rainforest is the perfect place to find plants and trees as part of its herbivorous diet.

In addition to this, the Javan rhinoceros faces threats related to habitat loss and fragmentation, as well as illegal poaching. As is the case with other rhino species, it’s believed by some that the horns are valuable as a medicine.

Looking at the Javan rhinoceros, you’ll notice that it has a slightly different appearance to other species. The horn is typically much smaller, which is why it’s sometimes called the lesser-horned rhino. The armored skin folds are very prominent, and this rhinoceros has a dark coloration.

Since we know that these beautiful animals are under threat, conservationists are putting great effort into restoring and protecting their remaining habitats. For example, these creatures need to get access to salt, which they do by entering the sea. But since many illegal fishing platforms have been erected, fewer rhinos have been since. In 2020, the Indonesian authorities employed marine patrols to ensure that the rhinos were able to gain access.

What’s more, owing to the extreme threat of extinction they face, Javan rhinoceroses are protected on a global scale, with worldwide organizations putting in efforts to create new conservation strategies. While there’s still a long way to go, many of these strategies are proving to be effective, as is demonstrated by the new rhinos I discussed earlier.

5. Sumatran Rhinoceros (Dicerorhinus sumatrensis)

The Sumatran rhinoceros is the smallest rhino species and looks unique with its two horns and hairy body. As their name suggests, these rhinos are found in Sumatra (and also Borneo), where they enjoy a tropical rainforest habitat with lots of dense vegetation since they’re herbivores and use their prehensile lips to pluck foliage from the trees.

It’s worth noting that there are three subspecies of this rhino, including the western Sumatran (Dicerorhinus sumatrensis sumatrensis), the northern Sumatran (Dicerorhinus sumatrensis lasiotis), and the eastern Sumatran, also known as the Bornean rhino (Dicerorhinus sumatrensis harrissoni). However, the northern Sumatran rhino is believed to be extinct.

Male Sumatran rhinos are incredibly territorial and will mark their territory with scents but will also use body language and vocalizations to communicate.

Sumatran rhinos can live for up to 45 years in the wild and they have the longest gestation period of all rhinoceros species. Females can be pregnant for between 15 and 16 months, after which, they give birth to a single calf.

Sadly, the Sumatran rhinoceros is listed as critically endangered, and according to IUCN, there may be as few as 30 left in the wild. Reports suggest that their numbers are dropping by as much as 13% every year. One of the main threats to this species is habitat loss as a result of deforestation, especially since the logging industry is big business in Sumatra. This has also led to habitat fragmentation. Poaching is also an issue where humans want to get their hands on the rhino’s horns for their alleged medicinal properties. However, it is illegal to poach rhinos in this part of the world.

Moreover, the Sumatran rhinoceros is an important seed disperser, so it plays a vital role within the ecosystem. It’s also known for its ability to maintain healthy biodiversity through vegetation control. To this end, conservation efforts are in place to preserve its habitat and research the species. What’s more, there are even captive breeding programs taking place to increase the number of Sumatran rhinoceroses. This includes the Sumatran Rhino Sanctuary that is currently home to seven individuals.

Conservation Efforts to Protect the Rhinoceros

While rhinoceroses do face a significant number of threats, there are many efforts in place to protect them and hopefully increase their populations.

Anti-Poaching Measures

Poaching is one of the biggest threats to rhinos, as their horns are highly prized, so implementing strategies to prevent this is essential. One of the primary things that authorities are doing is keeping a closer eye on this type of activity, and in many areas, they’ve even employed the use of drones to spot any illegal activity. It’s hoped that this will be enough to deter people in the knowledge that they could be caught and penalized. 

Since poachers will kill rhinos for their horns, in some places, drastic measures are having to be taken to prevent this which includes the humane removal of rhino horns. However, since males use their horns to fight, this means having to remove the horns of all local males so that individuals aren’t left more vulnerable. An operation like this can take hundreds of dollars per horn removal and must be repeated every two years but without them, the rhinos are of no interest to poachers.

Rhino horns are not the same as the horns of other animals and are actually tightly packed hairs that are so dense, they form something quite formidable. However, because of this composition, scientists have been able to create fake rhino horns that will hopefully be able to be sold in place of the real thing.

Save The Rhinos Trust was created in the 1980s and not only provides jobs for local people but has also seen great success in raising the populations of local rhinoceroses, proving that the strategies to prevent poaching are working. Since 2018, there has been a significant decline in the number of rhino poaching incidents.

Habitat Preservation & Restoration

Rhinoceroses are large grazing animals that need a lot of space to survive, but with habitats being depleted, this isn’t something that’s always available to them. Fortunately, there is a focus on expanding existing habitats and even establishing new areas within national parks and wildlife reserves.

These efforts may include things like managing current habitats, reforestation, and getting rid of invasive species that compete for resources with rhinos and other native animals. What’s more, humans are looking at the way in which they use the land to prevent further habitat fragmentation, which can be just as devastating as habitat loss.

An example of this is happening in Sumatra in order to support captive breeding programs. Two nearby areas have been cleared in the wild and prepared for replanting so that they’ll provide suitable habitat for new rhinos when they’re introduced to the wild.

In the Chitwan National Park in Nepal, more than 7,413 acres (3,000 hectares) of rhinoceros habitat has recently been restored, with plans for further work in the future. While over in Borneo, in the Tabin Wildlife Reserve, more than 1500 new trees have been planted, with more to come. 

International Cooperation

While rhinoceroses only exist in a small number of countries, the responsibility for protecting them falls on all of us. Without international cooperation, a lot of conservation efforts would fail. For example, the frozen eggs of the black rhino I discussed earlier were processed and stored in Europe, where there are no native rhinos.

Moreover, the United Kingdom has jumped on board, creating an agreement to do its bit in preventing illegal rhino poaching. On an even bigger scale, international agreements are being made at the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which allows proper regulation of the trading of rhino products around the globe.

Even in zoos around the world, conservation efforts are taking place. There are breeding programs to improve the numbers of rhinos as well as raising awareness to the 700 million people that visit zoos every year.

Community Engagement & Awareness

It would be impossible for a group of conservationists to save rhinoceros populations on their own. In order to be successful, they need the help of local communities, and this is most easily achieved by raising awareness and encouraging people to get involved.

But being involved doesn’t mean that locals are having to make any sacrifices. In fact, owing to things like job opportunities in ecotourism, this involvement can actually be beneficial. For example, a village in Zimbabwe where ecotourism is booming has realized the potential for income for local people and now fiercely protects their rhinoceros populations.

What’s more, by encouraging local people to get involved and take advantage of job opportunities, there’s hope that there will be less need to rely on illegal sources of income, such as rhino poaching.

But these opportunities alone aren’t always enough, and it’s vital that awareness is raised to press the importance of protecting these amazing animals. In Sumatra, conservationists are holding workshops to raise awareness and encourage locals to work with them to protect rhinos through things like proper land management. 

Conservation Breeding Programs

Since rhinoceroses may struggle to breed in the wild for various reasons, supporting their numbers through captive breeding programs is a must, and these are taking place all over the world. As I mentioned earlier, zoos are implementing breeding programs and these are showing huge levels of success. For example, Chester Zoo in the UK, has spearheaded the release of five new black rhinos into the wild, where this animal was once extinct.

The technology that’s now available means that breeding programs don’t even have to include the successful copulation of two rhinos. In the northern white rhino breeding efforts I talked about earlier, eggs were taken from a 20 year old female and artificially inseminated with the frozen sperm from a male that was no longer alive. These efforts could be enough to prevent certain species from going extinct. Similar efforts are being made in Sumatra with the help of German scientists.