Sumatran Rhinoceros

## About

A Sumatran rhinoceros.

The Sumatran rhinoceros ***(Dicerorhinus sumatrensis)*** is an Asian species of rhinoceros native to the Indonesian islands of Sumatra and Borneo. Unlike all other rhino species, the Sumatran rhino has a considerably amount of brown and black fur, giving them the title hairy or woolly rhino. This hair can be found most prolifically on their legs, chin and underbelly. The fur allows mud and dirt to cake to the rhino, protecting it from insect stings and bites. Oddly enough, the Sumatran rhino is the closest living relative of the ice age woolly rhino ***(Coelodonta antiquitatis)*** despite only resembling one another on a very basal level. The skin of the Sumatran rhino is unlike any other extant rhino species, being a more brown or even orange shade as opposed to the common grey of other rhinos. Sumatran rhinos have two very blunt horns, with the shorter of the two almost being flat rather than sharp. The possession of two horns in Asiatic rhinos is very rare among the species, as only two Asian rhino species have this attribute, with the other being the Javan rhinoceros ***(Rhinoceros sondaicus)***. Sumatran rhinos have very small eyes, which greatly inhibit their eyesight, making them rely greatly on their smelling and hearing abilities. This is a common trait in all rhino species, which leads the, to have a hyper aggressive attitude towards not only predators, but other rhinos. Sumatran rhinos can measure up to be 250cm (8.2ft) and weigh around 598-948kg (1,320-2,090lbs). Sumatran rhinos can also grow to be 1-1.5m (3.3-5ft) making them the smallest rhino species by quite a large margin.

## Diet

Sumatran rhinos are herbivorous eating leaves and grasses, as well as fruits such as wild mangoes and figs, which they seem to particularly enjoy. Sumatran rhinos have a prehensile upper lip, which allows them to grip leafy foliage from trees. This method of eating is used by many rhino species and is known as browsing.

## Conservation Status

The Sumatran rhino is currently listed as critically endangered by the IUCN. As their horns are a valuable ingredient in Chinese and East Asian remedies, Sumatran rhinos are impacted greatly by poaching. Rhinoceros horn is used prolifically in East Asian medicine and health products which promise great benefits after the consumption of rhinoceros horn. In reality, the effects of the consumption of rhinoceros horns in medicines, are non-existent at worst and questionable at best. Rhinoceros horn is usually grounded to a greyish-brown powder to be inserted in these products, and then proudly advertised on the product's branding, making it very apparent to the average customer as to what products contain rhino horn. The usage of rhino horn in medicinal products is not the only reason why rhino horn is so sought after however, less prominently rhino horn is often a means of producing jewelry or ornaments. These rhino-based jewelry however, are much less common in East Asian medicine, and are found more abundantly in African markets. Problems that the Sumatran rhino faces on a more personal level when compared to other rhino species is notably, the deforestation that occurs constantly throughout their range. The continued deforestation of Southeast Asian regions has not only devastated the Sumatran rhino population, but also lead to their extinction on mainland Asia after the death of the last Malaysian rhino, Iman on the 23rd of November, 2019. Iman's death also possibly marked the extinction of the West Sumatran rhinoceros, ***(Dicerorhinus sumatrensis sumatrensis)***, which was a possible subspecies of the Sumatran rhino. The production of palm oil in Southeast Asia is currently increasing rates of deforestation. This is because large amounts of forests are often cleared out, in favour of uniform pal oil plantations. The decrease in native biodiversity, and increase in man caused fatality, has destroyed the population of Sumatran rhinos, as well as other species such as tigers. has majorly fragmented the population of Sumatran rhinos, with most individuals being too far from each other to establish a breeding population.

## Range and Population

Today the Sumatran rhino only exists in Sumatra and possibly Indonesian Borneo. Sumatran rhinos are however, thought to have historically roamed across much of Mainland Asia from the foothills of the Himalayas in India, to the southern most points of Sumatra. A constant preference that both historical and extant Sumatran rhinos share, is their adaptability to rainforest environments. Sumatran rhinos are found modernly exclusively in dense humid jungles in both coastal and inland regions. A subspecies of the Sumatran rhino, the Bornean or Sabah rhino ***(Dicerorhinus sumatrensis harissoni)*** used to exist on Borneo however, the species current status is unknown, possibly being extinct. The population of the Sumatran rhino is known to be under 100 mature individuals and is estimated at 30-80. The continued deforestation of southeast Asia has lead to rhino population becoming severely fragmented, and when coupled with increased rarity, Sumatran rhinos have found it harder and harder to locate each other during the breeding season. Due to factors previously discussed, such as poaching, Sumatran rhinos are in a declining state, and their recovery depends on the intervention of humans. Efforts are being made to preserve the species (with limited success) such as gathering remaining captive zoo rhinos in the Way Kambas National Park, Indonesia, and currently accommodates eight individuals in its 100ha (247ac) area. The overall goal of Way Kambas is to eventually make a self-sustaining breeding population in order to be released into the wilderness of Sumatra.

## Behaviour

The Sumatran rhino, being covered in thick fur, often becomes very hot in the humid jungles of Sumatra. In order to combat the heat, the rhinos will wallow in water or mudholes. After wallowing the sticky mud will cake their fur, not only cooling the rhino down, but also creating an efficient shield from bugs. The barricade will successfully deter parasitic organisms, allowing the rhinos to protect themselves from diseases and harmful stings or bites. Sumatran rhinos will often spend almost the entire day in the wallows, traveling under the cover of the night. Female rhinos reach sexual maturity at around 6-7 years of age, whether as males will become sexually mature at age 10. The gestation period of the Sumatran rhino can last 15-16 months, with calves being born in the rainy season (October to March). Sumatran rhino females will give birth to a new calf around every 3-4 years, Until their calf is independent, the calf will stay situated near salt licks in dense vegetation, whilst the mother browses nearby. and their calf will gain their independence from their mother at 16-17 months, eventually attaining a solitary lifestyle. Similarly to other rhino species, Sumatran rhinos are solitary, only interacting with other individuals during breeding and courtship, as well as the mother's subsequent rearing of the offspring, and if two rhinos manage to encounter each other outside of these circumstances they will not stay united. More commonly two rhinos will almost never encounter each other, as rhinos make clearly defined territories. These territories are marked by scent, with feces and urine. Males have larger territories when compared to their female counterparts. Sumatran rhinos are known to move seasonally, escaping to higher elevations during floods, and descending during the cooler dry season. Rhinos will do this in part to escape insects, which are abundant during flood seasons.

### Relationship with Humans

Sumatran rhinos are rarely encountered by humans, and typically do not want anything to do with them. Usually if encountered, a Sumatran rhino will defecate and urinate copiously. This rather peculiar display serves as a means of distracting humans from their calf when threatened. Sumatran rhinos should not be approached by humans as often individuals can become aggressive when pursued and may attack. Occasionally Sumatran rhinos will ruin crops by trampling and grazing on them however, this is rare as the rhinos barely ever approach human settlements.

## In Captivity

Sumatran rhinos could once be found in many zoos from the USA to Australia. Zoos such as the Cincinnati and Bronx Zoo housed Sumatran rhinos, as well as the Australian Taronga Zoo. All of these zoos donated their rhinos to the breeding program, and these individuals are now situated in Way Kambas National Park, and may someday be a part of a sustainable breeding population.

## Sources

* IUCN Red List of Threatened Species - https://www.iucnredlist.org/species/6553/18493355
* its Time To Mix The Sumatran Rhino Subspecies | Mongabay News - https://news.mongabay.com/2018/05/geneticists-its-time-to-mix-the-sumatran-rhino-subspecies/
* Sumatran Rhinoceros | WWF - https://www.worldwildlife.org/species/sumatran-rhino
* Sumatran Rhinoceros | WWF Panda.org - https://wwf.panda.org/discover/knowledge\_hub/endangered\_species/rhinoceros/asian\_rhinos/sumatran\_rhinoceros/
* The Sumatran Rhino Sanctuary | Save The Rhino - https://www.savetherhino.org/programmes/the-sumatran-rhino-sanctuary/
* Sumatran Rhinoceros | International Rhino Foundation - https://rhinos.org/about-rhinos/rhino-species/sumatran-rhino/
* Sumatran Rhinoceros | Animal Diversity Web, University of Michigan Museum of Zoology - https://animaldiversity.org/accounts/Dicerorhinus\_sumatrensis/