Monday, 9 July 2012

Wild Water Buffalo

The wild water buffalo (Bubalus arnee), also called Asian buffalo and Asiatic buffalo, is a large bovine native to Southeast Asia. The species is listed as endangered on the IUCN Red List since 1986, as the remaining population totals less than 4,000, with an estimate of fewer than 2,500 mature individuals.
The global population has been estimated at 3,400 individuals, of which 3,100 (91%) live in India, mostly in Assam.
The wild water buffalo is the ancestor of the domestic water buffalo, and the second-largest wild bovid, smaller only than the gaur.
The slightly smaller African buffalo or Cape buffalo (Syncerus caffer) is not closely related to the water buffalo.

Characteristics

 

Horn differences between Cape buffalo (above) and water buffalo (below) - the two groups are not closely related.

Wild water buffalo are larger and heavier than domestic buffalo, and weigh from 700 to 1,200 kg (1,500 to 2,600 lb). Their head-to-body-length is 240 to 300 cm (94 to 120 in) with a tail 60 to 100 cm (24 to 39 in) long, and a shoulder height of 150 to 190 cm (59 to 75 in). Both sexes carry horns that are heavy at the base and widely spreading up to 2 m (79 in) along the outer edges, exceeding in size the horns of any other living bovid. Their skin color is ash gray to black. The moderately long, coarse and sparse hair is directed forward from the haunches to the long and narrow head. There is a tuft on the forehead, and the ears are comparatively small. The tip of the tail is bushy; the hooves are large and splayed.

Distribution and habitat

 

Landscape in Kaziranga National Park with a herd of water buffaloes in the background

Wild water buffalos occur in India, Nepal, Bhutan, Thailand, and Cambodia, with an unconfirmed population in Myanmar. They have been extirpated in Pakistan, Bangladesh, Laos and Vietnam. They are associated with wet grasslands, swamps and densely vegetated river valleys.
In India, they are largely restricted to in and around Kaziranga, Manas and Dibru-Saikhowa National Parks, Laokhowa and Burhachapori Wildlife Sanctuaries and a few scattered pockets in Assam; in and around D'Ering Memorial Wildlife Sanctuary in Arunachal Pradesh; a small population in Buxa Tiger Reserve northern West Bengal; Balpakram National Park Meghalaya and in Madhya Pradesh in the Indravati National Park and the Udanti Wildlife Sanctuary. This population might extend into adjacent parts of Orissa. In the early 1990s, there may still have been about 3,300–3,500 wild buffaloes in Assam and the adjacent states of northeast India. In 1997, the number was assessed at less than 1,500 mature individuals.
Many surviving populations are believed to have interbred with domestic or feral water buffalos. In the late 1980s, fewer than 100 wild buffaloes were left in Madhya Pradesh. By 1992, only 50 animals were estimated to have survived there.

Nepal's only population lives in the Koshi Tappu Wildlife Reserve, and comprised 219 individuals in 2009. This small population is currently seriously threatened.
In and around Bhutan's Royal Manas National Park, a small number of wild water buffaloes occur. This is part of the subpopulation that occurs in India's Manas National Park. In Myanmar, a few wild-living animals independent of human husbandry live in the Hukaung Valley Tiger Reserve.
In Thailand, wild buffaloes have been reported to occur in small herds of less than 40 individuals. A population of 25–60 individuals inhabited lowland areas of the Huai Kha Khaeng Wildlife Sanctuary between December 1999 and April 2001. This population has not grown significantly in 15 years, and may be interbreeding with domestic water buffalo.
The population in Cambodia is confined to a small area of easternmost Mondulkiri and possibly Ratanakiri Provinces. Only a few dozen individuals remain.
Populations found elsewhere in Asia are feral breeds. They were introduced to northern Australia, Argentina and Bolivia.

Ecology and behavior

 

Wild water buffalos are both diurnal and nocturnal. Adult females and their young form stable clans of as many as 30 individuals that have home ranges of 170 to 1,000 ha (0.66 to 3.9 sq mi), including areas for resting, grazing, wallowing and drinking. Clans are led by old cows, even when bulls accompany the group. Several clans form a herd of 30 to 500 animals that gather at resting areas. Adult males form bachelor groups of up to 10 individuals, with older males often solitary, and spend the dry season apart from the female clans. They are seasonal breeders in most of their range, typically in October and November. However, some populations breed year round. Dominant males mate with the females of a clan who subsequently drive them off. Their gestation period lasts 10 to 11 months, with an interbirth interval of one year. They typically give birth to a single offspring, although twins are possible. Age at sexual maturity is 18 months for males, and three years for females. The maximum known lifespan is 25 years in the wild. In the wild in Assam, the herd size varied from three to 30 individuals.
They are probably grazers by preference, feeding mainly on true grasses when available, such as scutch grass, and sedges, but they also eat herbs, fruits, and bark, as well as browsing on trees and shrubs. They also feed on crops, including rice, sugarcane, and jute, sometimes causing considerable damage.

Threats

 

A population reduction by at least 50% over the last three generations seems likely given the severity of the threats, especially hybridization; this population trend is projected to continue into the future. The most important threats are:
  • interbreeding with feral and domestic buffalo in and around protected areas;
  • hunting, especially in Thailand, Cambodia, and Myanmar;
  • habitat loss of floodplain areas due to conversion to agriculture and hydropower development;
  • degradation of wetlands due to invasive species such as stem twiners and lianas;
  • diseases and parasites transmitted by domestic livestock;
  • interspecific competition for food and water between wild buffalo and domestic stock.
Tigers prey on adult wild water buffalo, and Asian black bears have also been known to kill them. The smaller and less aggressive domestic water buffalo can be taken by the saltwater crocodile (Crocodylus porosus), which rarely, if ever, encounters the wild buffalo species.

Conservation

 

Bubalus arnee is included in CITES Appendix III, and is legally protected in Bhutan, India, Nepal, and Thailand.

Taxonomy

 

Water buffalo sculpture, Lopburi, Thailand, 2300 BCE

Carl Linnaeus applied the binomial Bos bubalis to the domestic water buffalo in his first description of 1758. In 1792, Robert Kerr applied the binomial Bos arnee to the wild species occurring in India north from Bengal. Later authors subordinated the species under either Bos, Bubalus or Buffelus.
In 2003, the International Commission on Zoological Nomenclature fixed the first available specific name based on a wild population that the name for this wild species is valid by virtue of its being antedated by a name based on a domestic form. Most authors have adopted the binomial Bubalus arnee for the wild species as valid for the taxon.
The river buffalo Bubalus bubalis bubalis and carabao or swamp buffalo Bubalus bubalis carabanensis are both derived from the wild water buffalo, and are the product of thousands of years of selective breeding carried out either in South Asia or Southeast Asia.

Modern uses

 

Wildlife and conservation scientists have started to recommend and use introduced populations of feral domestic water buffalo in far away lands to manage uncontrolled vegetation growth in and around natural wetlands. Introduced water buffalo at home in such environs provide cheap service by regularly grazing the uncontrolled vegetation and opening up clogged water bodies for waterfowl, wetland birds and other wildlife.