The gaur ( Bos gaurus; ), also known as the Indian bison, is a large bovine native to the Indian subcontinent and Southeast Asia, and has been listed as Vulnerable on the IUCN Red List since 1986. The global population was estimated at a maximum of 21,000 mature individuals in 2016, with the majority of those existing in India. It is the largest species among the wild cattle and the Bovidae.
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.Simoons, F. J. (1984). Gayal or mithan. In: Mason, I. L. (ed.) Evolution of Domesticated Animals. Longman, London. Pages 34–38.
The Hindi word गौर means 'fair-skinned, fair, white'.
To date, three gaur subspecies have been recognized:
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 Genetics study.
Within the genus Bos, the gaur is most closely related to the banteng ( Bos javanicus) and the probably now extinct kouprey ( Bos sauveli), which are also native to Southeast Asia. Relationships of members of the genus Bos based on nuclear genomes after Sinding, et al. 2021.
The gaur has a distinct dewlap on the throat and chest. Both sexes have horns, which grow from the sides of the head, curving upwards. Between the horns is a high convex ridge on the forehead. At their bases the horns present an elliptical cross-section, a characteristic that is more strongly marked in bulls than in cows. They are decidedly flattened at the base and regularly curved throughout their length, and are bent inward and slightly backward at their tips. The colour of the horns is pale green or yellow throughout the greater part of their length, but the tips are black. The horns, of medium size by large bovid standards, grow to a length of .
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.
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. Body mass ranges widely from in adult females and in adult males. 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 .
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. The Chitwan population has increased from 188 to 368 animals in the years 1997 to 2016. Census conducted in Parsa National Park confirmed the presence of 112 gaur in the same period.
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. Major populations of about 2,000 individuals have been reported in both Nagarahole and Bandipur National Parks, over 1,000 individuals in Tadoba Andhari Tiger Project, 500–1,000 individuals in both Periyar Tiger Reserve and Silent Valley and adjoining forest complexes, and over 800 individuals in Bhadra Wildlife Sanctuary. Trishna Wildlife Sanctuary in southern Tripura is home to a significant number of 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 Bangladesh, a few gaur occur in the Chittagong Hill Tracts, mostly in Banderban district. During a camera trap project, few gaur were recorded indicating that the population is fragmented and probably declining.
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.
In Cambodia, the gaur population declined considerably in the period from the late 1960s to the early 1990s. The most substantial population of the country remained in Mondulkiri Province, where up to 1,000 individuals may have survived up to 2010 in a forested landscape of over . Results of 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.
In China, the gaur was present up to the 34th parallel north during the late Neolithic period about 5,200 years Before Present. 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 2016, it was estimated that the global population has declined by more than 70% in Indochina and Malaysia during the last three generations of 24–30 years, and that the gaur is Local extinction in Sri Lanka. Populations in well-protected areas appeared to be stable.
In January and February, gaur live in small herds of eight to 11 individuals, one of which is a bull. In April or May, more bulls may join the herd for mating, and individual bulls may move from herd to herd, each mating with many cows. In May or June, they leave the herd and may form herds of bulls only or live alone. Herds wander each day. Each herd has a nonexclusive home range, and sometimes herds may join in groups of 50 or more.
Gaur herds are led by an old adult female, the matriarch. Adult males may be solitary. During the peak of the breeding season, unattached males wander widely in search of receptive females. No serious fighting between males has been recorded, with size being the major factor in determining dominance. Males make a mating call of clear, resonant tones which may carry for more than . Gaur have also been known to make a whistling snort as an alarm call, and a low, cow-like moo.
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.
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.
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.
Characteristics
Distribution and habitat
Ecology and behaviour
Feeding ecology
Reproduction
Natural predators
Threats
Conservation
In captivity
See also
Further reading
External links
Notes
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