| Borneo Elephant | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Proboscidea |
| Family: | Elephantidae |
| Genus: | Elephas |
| Species: | E. maximus |
| Subspecies: | E. m. borneensis |
| Trinomial name | |
| Elephas maximus borneensis Deraniyagala, 1950 |
|
The Borneo Elephant also called the Borneo Pygmy Elephant inhabits northeastern Borneo. Its origin remains the subject of debate. A definitive subspecific classification as Elephas maximus borneensis awaits a detailed range-wide morphometric and genetic study. Since 1986, Elephas maximus has been listed as endangered by IUCN as the population has declined by at least 50% over the last three generations, estimated to be 60–75 years. The species is pre-eminently threatened by habitat loss, degradation and fragmentation.[1]
The Sultan of Sulu introduced captive elephants to Borneo in the 18th century, which were released into the jungle.[2] Comparison of the Borneo elephant population to putative source populations in DNA analysis indicates that the Borneo elephants are derived from Sundaic stock and indigenous to Borneo. The genetic divergence of Borneo elephants warrants their recognition as a separate Evolutionary Significant Unit.[3]
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In general, Asian elephants are smaller than African elephants and have the highest body point on the head. The tip of their trunk has one finger-like process. Their back is convex or level. Females are usually smaller than males, and have short or no tusks.[4]
It has become commonplace to refer to Borneo elephants as a ‘pygmy’ subspecies. But adult elephants of Sabah of both sexes are similar in height to their counterparts in Peninsular Malaysia. Five measurements of the skull of a fully adult female elephant from Gomantong Forest Reserve were slightly smaller (72 – 90%) than comparable dimensions averaged for two Sumatran skulls. Few available measurements show that they are of similar size to other populations of the Sunda subregion.[2]
Morphological measurements of fifteen captive elephants from Peninsular Malaysia and of six elephants from Sabah were taken between April 2005 and January 2006, and repeated three times for each elephant and averaged. There was no significant difference in any of the characters between the two captive populations.[5]
They are also remarkably tame and passive, another reason some scientists think they descended from a domestic collection.[3][6]
Elephants have been confined to the northern and northeastern parts of Borneo.[7] In the 1980s, there were two distinct populations in Sabah ranging over the Tabin Wildlife Reserve and adjacent mostly logged dipterocarp forest on steep terrain; and in the hilly interior at about 300 to 1,500 m (980 to 4,900 ft) altitude in dipterocarp forest, which was largely undisturbed at the time, and only logged at the periphery. In Kalimantan, their range is restricted to a small contiguous area of the upper Sembakung River in the east.[8]
Previous estimations for the population in Sabah have ranged between 500-2000 elephants. Between July 2007 and December 2008, wildlife biologists conducted an elephant population census in five main elephant managed ranges in Sabah using a systematic line transect survey and a long term monitoring of dung decay rates. They estimated a population of 2,040 elephants. The largest of the five populations inhabits the unprotected central forests of Sabah, a contiguous area of forest which is largely commercial forest, where 1,132 elephants were estimated to remain. Elephant density (elephants per square kilometre) was found to be highest where neighbouring habitat had been destroyed and the remaining elephants squeezed into the remaining forest areas.[9]
The range of wild elephants in Sabah and Kalimantan seems to have expanded very little in the past 100 years despite access to suitable habitat elsewhere on Borneo. Borneo’s soil tends to be young, leached and infertile, and there is speculation that the distribution of wild elephants on the island may be limited by the occurrence of natural mineral sources.[10]
It has not been resolved whether Borneo elephants are indigenous or have descended from captive elephants presented to the Sultan of Sulu in 1750 by the East-India Company and later set free in northern Borneo.[8]
In the 19th century, a zoological exploration established that wild elephants occurred naturally in a restricted region of northeastern Borneo. The status and taxonomic distinctiveness of the Borneo elephants has been controversial since then. In 1940, Frederick Nutter Chasen considered Bornean elephants as descendants of an introduced stock, and placed them in the subspecies Elephas maximus indicus. Reginald Innes Pocock having studied specimens in the British Museum of Natural History disagreed in 1943, and placed all Sundaic elephants in the subspecies Elephas maximus sumatrensis. In 1950, Paules Edward Pieris Deraniyagala described a subspecies Elephas maximus borneensis, taking as his type an illustration in the National Geographical Magazine, but not a living elephant in accordance with the rules of the International Code of Zoological Nomenclature.[2]
In 2003, the debate was re-opened by a suggestion that the introduced Sulu elephants and the north-east Borneo population might have descended from the now extinct Javan elephant, which was named Elephas maximus sondaicus by Deraniyagala. This hypothesis is based on missing archaeological evidence of long term elephant habitation in Borneo, a corroboration in folklore and that elephants have not colonized the entire island of Borneo.[11] If Borneo elephants are in fact Javan elephants, they represent the only successful elephant translocation[12].
In 2003, Mitochondrial DNA analysis and microsatellite data indicated that the extant population is derived from Sundaic stock but has undergone independent local evolution for some 300,000 years since a postulated Pleistocene colonisation, and possibly became isolated from other Asian elephant populations when land bridges that linked Borneo with the other Sunda Islands and the Asian mainland disappeared after the Last Glacial Maximum 18,000 years ago.[3]
Elephants were appropriate gifts from one ruler to another, or to a person of high standing, and it was customary to transport them by sea. In about 1395, the Raja of Java gave two elephants to the ruler Raja Baginda of Sulu. These animals were reputedly the founders of a feral population at the western end of Borneo. When in 1521 the remnants of Ferdinand Magellan’s circumnavigation of the Earth reached Brunei, the chronicler of the voyage recounted that the delegation from the flagship Victoria was conveyed to and from the ruler’s palace on elephants caparisoned in silk. This custom had been discontinued by the time later visitors arrived in Brunei in the 1770s, who reported wild-living elephant herds that were hunted by local people after harvest. Despite the early records of royal elephants in Brunei and Banjarmasin, there was no tradition of capturing and taming local wild elephants in Borneo.[2]
The arrival of elephants in the north Kalimantan region of Borneo coincides with the rule of the Sultans of Sulu over Sabah. The Sultanate of Sulu enjoyed peaceful ties with the Hindu Sultanate of Java. As a token of appreciation, the rulers of Java sent their elephants to Sulu, much as they have sent Javanese elephants to the Sultanate of Maguindanao, which also partly gives the reason why skeletal remains of small elephants are found in Mindanao, south Philippines. The Sultan of Sulu and his family shipped some of their prized Javanese elephants to northeast Borneo due to lack of land and for the elephants to help in hauling logs out of the forest to create fast and long ship vessels. When this lease was signed, most of these timid and largely domesticated small elephants under the employ of Sulu's shipbuilders and traders were released into the forests so they can live deep inside the jungle away from any feuding sultan who might use them for war. This single act of releasing the pachyderms to the wild made the Bolkiah family of Sulu and their allies the savior of what remaining elephants are left, old locals attest.
Wild Asian elephant populations are disappearing as deforestation in Borneo disrupts their migration routes, depletes their food sources, and destroys their habitat. Recognizing these elephants as native to Borneo makes their conservation a high priority and gives biologists important clues about how to manage them.[13]
Elephas maximus is listed on CITES Appendix I.[1]
The genetic distinctiveness of Borneo elephants makes them one of the highest priority populations for Asian elephant conservation.[3]
In Malaysia, the Borneo elephants are protected under schedule II of the Wildlife Conservation Enactment. Any person found guilty of hunting elephants is liable on conviction to a fine of $RM 50,000 or five years imprisonment or both.[10]
The Oregon Zoo in Portland has the only Borneo elephant in the United States, a seventeen-year-old female orphan called Chendra. There are plans to breed Chendra with the zoo's Tusko.