Gaur


The gaur, 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 and Bangladesh with Myanmar and Yunnan, China.

Etymology

The Sanskrit word गौर means 'white, yellowish, reddish'. The Sanskrit word means a kind of water buffalo.
The Hindi word गौर means 'fair-skinned, fair, white'.

Taxonomy

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:
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.
Within the genus Bos, the gaur is most closely related to the banteng and the probably now extinct kouprey, which are also native to Southeast Asia. Relationships of members of the genus Bos based on nuclear genomes after Sinding, et al. 2021.

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. 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.
File:White bison by N A Nazeer.jpg|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 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.

Distribution and habitat

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.
It is largely confined to evergreen forests or semi-evergreen and moist deciduous forests, but also inhabits deciduous forest areas at the periphery. Gaur habitat is characterized by large, relatively undisturbed forest tracts, hilly terrain below an elevation of, availability of water, and an abundance of forage in the form of grasses, bamboo, shrubs, and trees. Its apparent preference for hilly terrain may be partly due to the earlier conversion of most of the plains and other low-lying areas to croplands and pastures. It occurs from sea level to an elevation of at least. Low-lying areas seem to comprise optimal habitat.
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 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.
In China, the gaur was present up to the 34th parallel north during the late Neolithic period about 5,200 years BP. 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 locally extinct in Sri Lanka. Populations in well-protected areas appeared to be stable.