White Rhinoceros (Ceratotherium simum)

White rhinoceroses, also known as Square-lipped Rhinoceroses, rank among the largest land mammals. Their substantial weight can range from 2,200 to almost 8,000 pounds. 

Plate-like folds complement their thick, pale grey skin. This density is clearly noticeable and quite impenetrable. They also sport a long neck with a hump, two uneven horns, a small set of eyes as compared to their body size, and a square-shaped lip. 

Interestingly, the term "white" in their name is a misunderstood translation of "wide" in reference to their broad mouths.

They are native to the vast regions of southern Africa. However, now, their presence is limited to certain areas. While the Northern White Rhino subspecies was once found in the Democratic Republic of Congo, the Southern White Rhino subspecies is more spread across regions like Botswana, Namibia, and Zimbabwe and protected areas like Kruger National Park.

They have a long gestation period spanning approximately 530 to 550 days. Consequently, their breeding interval lasts long, ranging between 2.5 to 3 years.

These types of rhinos are herbivorous, primarily consuming thick bush covers and short grasses. They play a crucial role in maintaining biodiversity and preventing wildfires. However, their existence is threatened due to high poaching activity, fueled mainly by illegal rhino horn demand in Southeast Asia.

The number of white rhinos could decline drastically without substantial conservation measures. Hence, the status of this African rhino species is pegged as Near Threatened. 

Unfortunately, the Northern White Rhino subspecies are critically endangered1, with unconfirmed reports of surviving members in remote areas of South Sudan.

Black Rhinoceros (Diceros bicornis)

The Black Rhinoceros is widespread in southern and eastern Africa, effortlessly adapting to grasslands, deserts, and tropical forests.

The African rhinos' general skin color is grey, with some variance to yellow-brown or dark brown. Distinctively, the color tends to match the soil of their individual habitats. Apart from short, fringe-like hair on their ears, the rhino's skin is largely hairless.

In terms of size, males typically exceed females, with an average weight scale tipping between 1,700 and 3,000 pounds. This robust animal brandishes two uneven horns, with some showcasing a small third horn at the posterior.

Unlike the previously mentioned species, Black Rhinos have a pointed, prehensile upper lip that facilitates the feeding process. They leverage this advantage while browsing for their diet, primarily consisting of twigs, woody shrubs, and small trees.

Notably, the Black Rhino forms a mutualistic association with the oxpeckers. The bird not only feeds on the parasites on the rhino’s skin but also warns of incoming predators. 

Unfortunately, the Black Rhinoceros is listed as Critically Endangered owing to heavy poaching for rhino horns in the late 20th century4, despite better protection and management. However, numbers have improved since the mid-90s.

Indian Rhinoceros (Rhinoceros unicornis)

The Indian rhinoceros, widely recognized as the Greater One-horned Rhino, resides primarily in the damp alluvial plains of northern India. Wallows and river dips form part of their daily routine. At the same time, dry savanna grasslands and eastern Himalayan deciduous forests serve as additional habitats.

The Indian Rhino has gray-brown skin that folds around its hind and front legs. Thanks to the single horn atop its snout, it can be spotted from a mile away, distinguishing it from its African counterparts.

As generalist herbivores, an Indian rhino's diet revolves around grasses. Still, they are open to branching out to fruits, flowers, twigs, and even grains like rice. 

Strict protection and habitat management have recently allowed their population to increase slowly. However, 70% of the rhino population lives in Assam's Kaziranga National Park. A single disaster in this area could be devastating. Thus, Great One Horned Rhinos are a vulnerable species.

Javan Rhinoceros (Rhinoceros sondaicus)

The Javan rhinoceros, commonly known as the lesser-one-horned rhino, presents quite the ecological conundrum. Historically native to Southeast Asia, their modern populace is resigned to the confines of Java's Ujung Kulon Nature Reserve.

Critically endangered, the rhino population is at an estimated 683, with only a third considered reproductive. This decline links directly to the rising demand for their horn for traditional medicine.

Another contributing factor is habitat loss, led by human encroachment. Equally damaging is the proliferation of the local langkap palm, stifling the growth of the rhino's food plants.

Javan rhino sports the smallest horn of its genus, a mere 10-inch protrusion in males, while females do not have them at all. Its distinct grey hide is characterized by sectional creases stemming from rigid folds.

Primarily a herbivore, Javan Rhinos do not eat grass but prefer softer vegetation, preferring figs and guest-tree plants.

Sumatran Rhinoceros (Dicerorhinus sumatrensis)

Our last type of rhino is the Sumatran rhinoceros, also known as the Hairy Rhinoceros. It was historically found in regions spanning from Assam, Burma, and Indochina to Malaysia, northern Sumatra, and northwestern Borneo. Today, it only resides in national parks in Sumatra and Malaysia.

It has fringed ears, two horns, reddish-brown skin cloaked in long hair, and distinct wrinkles around its eyes. The dense hair aids in layering mud on the rhino's skin, forming a natural cooling system in hot weather. 

The Sumatran rhino is also the smallest of the rhinoceros family, weighing between 1,300 to 2,200 pounds. These two-horned creatures have an adaptive dietary habit. They are generalist herbivores, feeding primarily on leaves and twigs from saplings and small trees.

Unfortunately, the Sumatran Rhinos are critically endangered2. Habitat loss due to encroachment, poaching, human disturbance, and habitat fragmentation has led to an 80% reduction in population over the last three generations. 

Today, less than 30 mature individuals are estimated to exist, with a projected probability of extinction at 90% within three generations without proactive interventions.