Gaur

The gaur (Bos gaurus; ), also known as the Indian bison,

The domesticated gayal or mithun originated partly from the wild gaur and is most common in the border regions of Northeast India (Assam, Manipur, Nagaland) and Bangladesh with Myanmar and Yunnan, China.

Etymology

The Sanskrit word means 'white, yellowish, reddish'. The Sanskrit word means a kind of water buffalo.

The Hindi word means 'fair-skinned, fair, white'.

Taxonomy

thumb|Bos gaurus grangeri skeleton

Bison gaurus was the scientific name proposed by Charles Hamilton Smith in 1827. Later authors subordinated the species under either Bos or Bibos.

To date, three gaur subspecies have been recognized:

B. g. gaurus; the nominate subspecies, ranges in India, Nepal and Bhutan.
B. g. hubbacki; described by Lydekker in 1907, based on a specimen from Pahang in Peninsular Malaysia.

In 2003, the International Commission on Zoological Nomenclature fixed the valid specific name of the wild gaur as the first available name based on the wild population, despite being antedated by the name for the domestic form. Most authors have adopted the binomial Bos gaurus for the wild species as valid for the taxon.

In recognition of phenotypic differences between zoological specimens of Indian and Southeast Asian gaur, the trinomials Bos gaurus gaurus and Bos gaurus laosiensis are provisionally accepted, pending further morphometric and genetic study.

Characteristics

The gaur is the largest living bovid. It is a strong and massively built bovine with a high convex ridge on the forehead between the horns that protrudes anteriorly, causing a deep hollow in the profile of the upper part of the head. There is a prominent ridge on the back. The ears are very large. In old bulls, the hair becomes very thin on the back. The adult male is dark brown, approaching black in very old individuals. The upper part of the head, from above the eyes to the nape of the neck, is ashy grey or occasionally dirty white. The muzzle is pale coloured, and the lower part of the legs is pure white or tan. Cows and young bulls are paler and in some instances have a rufous tinge, which is most marked in groups inhabiting dry and open areas. The tail is shorter than in typical oxen, reaching only to the hocks. They have a distinct ridge running from the shoulders to the middle of the back; the shoulders may be as much as higher than the rump. This ridge is caused by the great length of the spinous processes of the vertebrae of the fore-part of the trunk as compared with those of the loins. The hair is short, fine and glossy; the hooves are narrow and pointed.

The gaur has a distinct dewlap on the throat and chest.

The cow is considerably lighter in colour than the bull. Cows' horns are more slender and upright with more inward curvature and a frontal ridge that is scarcely perceptible. In young animals the horns are smooth and polished, while in old bulls they are rugged and dented at the base.

thumb|[[Albino gaur or Manjampatti white bison in Chinnar Wildlife Sanctuary, Kerala]]

The gaur has a head-and-body length of with a long tail, and is high at the shoulder, averaging about in females and in males. At the top of its muscular hump just behind its shoulder, an average adult male is just under tall and the male's girth at its midsection (behind its shoulders) averages about . Males are about one-fourth larger and heavier than females. In general, measurements are derived from gaurs surveyed in India. In a sample of 13 individuals in India, gaur males averaged about and females weighed a median of approximately . In China, the shoulder height of gaurs ranges from , and bulls weigh up to .

Distribution and habitat

thumb|A herd at a [[mineral lick in Nagarhole National Park, Karnataka]]

thumb|A male grazing in the grasslands of Trishna Wildlife Sanctuary, Tripura

thumb|In [[Satpura National Park, Madhya Pradesh]]

The gaur historically occurred throughout mainland South and Southeast Asia, including Nepal, India, Bhutan, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam and China. Today, its range is seriously fragmented, and it is regionally extinct in Peninsular Malaysia and Sri Lanka.

In Nepal, the gaur population was estimated to be 250–350 in the mid-1990s, with the majority in Chitwan National Park and the adjacent Parsa National Park. These two parks are connected by a chain of forested hills. Population trends appeared to be relatively stable.

In India, the population was estimated to be 12,000–22,000 in the mid-1990s. The Western Ghats and their outflanking hills in southern India constitute one of the most extensive extant strongholds of gaur, in particular in the Wayanad – Nagarhole – Mudumalai – Bandipur complex. The populations in India, Bhutan and Bangladesh are estimated to comprise 23,000–34,000 individuals.

In Bhutan, they apparently persist all over the southern foothill zone, notably in Royal Manas National Park, Phibsoo Wildlife Sanctuary and Khaling Wildlife Sanctuary.

In Thailand, the gaur once occurred throughout the country, but fewer than 1,000 individuals were estimated to have remained in the 1990s. In the mostly semi-evergreen Dong Phaya Yen Mountains, it was recorded at low density at the turn of the century, with an estimated total of about 150 individuals.

In Vietnam, the gaur occurred in several areas in Đắk Lắk Province in 1997. Several herds persist in Cát Tiên National Park and in adjacent state forest enterprises. The current status of the gaur population is poorly known; it may be in serious decline. Results of camera trapping carried out in 2009 suggested a globally significant gaur population in Sre Pok Wildlife Sanctuary and the contiguous Phnom Prich Wildlife Sanctuary. Line transect distance sampling in Keo Seima Wildlife Sanctuary revealed around 500 individuals in 2010, but only 33 individuals were encountered in 2020. Encounter rates in Sre Pok Wildlife Sanctuary and Phnom Prich Wildlife Sanctuary in 2020 were low with 0-5 individuals sighted in long transects.

In Laos, up to 200 individuals were estimated to inhabit protected area boundaries in the mid-1990s. They were reported discontinuously distributed in low numbers. Overhunting had reduced the population, and survivors occurred mainly in remote sites. Fewer than six National Biodiversity Conservation Areas held more than 50 individuals. Areas with populations likely to be nationally important included the Nam Theun catchment and the adjoining plateau. Subsequent surveys carried out a decade later using fairly intensive camera trapping did not record any gaur any more, indicating a massive decline of the population. Now it occurs only in heavily fragmented populations in Yunnan and southeastern Tibet. By the 1980s, it was extirpated in Lancang County, and the remaining animals were split into two populations in Xishuangbanna–Simao District and Cangyuan. In the mid-1990s, a population of 600–800 individuals may have lived in Yunnan Province, with the majority occurring in Xishuangbanna National Nature Reserve.

In some regions in India where human disturbance is minor, the gaur is very timid and shy despite its great size and power. When alarmed, gaur crash into the jungle at a surprising speed. However, in Southeast Asia and South India, where they are used to the presence of humans, gaur are said by locals to be very bold and aggressive. They are frequently known to go into fields and graze alongside domestic cattle, sometimes killing them in fights. Gaur bulls may charge without provocation, especially during summer, when the intense heat and parasitic insects make them more short-tempered than usual. To warn other members of its herd of approaching danger, the gaur lets out a high whistle for help.

During a survey in the Bhagwan Mahaveer Sanctuary and Mollem National Park, gaurs were observed to feed on 32 species of plants. They consume herbs, young shoots, flowers, fruits of elephant apple (Dillenia) with a high preference for leaves. Food preference varies by season. In winter and monsoon, they feed on preferably fine and fresh true grasses and herb species of the legume family, such as tick clover (Desmodium triflorum), but also browse on leaves of shrub species such as karvy (Strobilanthes callosus), Indian boxwood (Gardenia latifolia), mallow-leaved crossberry (Grewia abutifolia), East-Indian screw tree (Helicteres) and the chaste tree (Vitex negundo). In summer, they also feed on bark of teak (Tectona grandis), on fruit of golden shower tree (Cassia fistula), and on the bark and fruit of cashew (Anacardium occidentale). Gaur spent most of their daily time feeding. Peak feeding activity was observed between 6:30 and 8:30 in the mornings and between 17:30 and 18:45 in the evenings. During the hottest hours of the day, they rest in the shade of big trees.

They may debark trees due to shortages of preferred food, and of minerals and trace elements needed for their nutrition, or for maintaining an optimum fiber/protein ratio for proper digestion of food and better assimilation of nutrients. They may turn to available browse species and fibrous teak bark in summer as green grass and herbaceous resources dry up. High concentrations of calcium (22400 ppm) and phosphorus (400 ppm) have been reported in teak bark, so consumption of teak bark may help animals to satisfy both mineral and other food needs. Long-term survival and conservation of these herbivores depend on the availability of preferred plant species for food. Hence, protection of the historically preferred habitats used by gaur is a significant factor in conservation biology.

Natural predators

Due to its size and power, the gaur has few natural predators besides humans. Leopards, dhole packs and large mugger crocodiles occasionally attack unguarded calves or unhealthy animals. Only tigers and saltwater crocodiles have been reported to kill adult gaur. However, the habitat and distribution of the gaur and saltwater crocodile seldom overlap in recent times, due to the decreasing range of both species. A crocodile likely would need to be a mature adult male of more than and to make a successful attack on a healthy adult gaur.

thumb|A tiger with gaur carcass

Tigers hunt young or infirm gaur, but have also been reported to have killed healthy bulls weighing at least . When confronted by a tiger, the adult members of a gaur herd often form a circle surrounding the vulnerable young and calves, shielding them from the big cat. As tigers rely on ambush attacks when taking on prey as large as a gaur, they will almost always abandon a hunt if detected and met in this manner. A herd of gaur in Malaysia encircled a calf killed by a tiger and prevented it from approaching the carcass. Nevertheless, the gaur is a formidable opponent to the tiger and capable of killing tigers in self-defence.

Threats

In Laos, the gaur is highly threatened by poaching for trade to supply international markets, but also by opportunistic hunting, and specific hunting for home consumption.

References

External links

Herd of about 30 Indian Gaur at Sathyamangalam Forests
Tigers hunt Largest Wild Cattle Gaurs !
Video of tigers and gaurs
Video of gaur
ARKive: images and movies of the gaur (Bos frontalis)
Images of Indian gaur
Gaur in Bandhipur
Tiger kills adult Gaur
The Hindu.com: A date with bisons in Madurai
The Hindu.com: Bison recolonising Jawadhu Hills, says forest official