Gaur

The **gaur** (/ˈɡaʊər/, *Bos gaurus*), also called **Indian bison**, is the largest extant bovine, native to South Asia and Southeast Asia. The species has been listed as vulnerable on the IUCN Red List since 1986, as the population decline in parts of the species' range is likely to be well over 70% during the last three generations. Population trends are stable in well-protected areas, and are rebuilding in a few areas which had been neglected. The gaur is the tallest species of wild cattle. The Malayan gaur is called *seladang*, and the Burmese gaur is called *young.* The domesticated form of the gaur *Bos frontalis* is called *gayal* or *mithun*.

## Taxonomy

The type locality is North-East of Chittagong in Bangladesh. Some authors treat the wild and domestic forms of gaur as separate species *Bos gaurus* and *Bos frontalis*. The domestic gaur, also called gayal, mithan or mithun, (*Bos frontalis*) is probably the result of crossbreeding with domestic cattle. Currently, the two forms are considered synonymous, and the domestic species is designated equally as *Bos gaurus* or *Bos frontalis*. The gaur is the member of the subgenus *Bibos* (Hodgson, 1837) with the banteng and the kouprey, and it was at one time elevated to a genus. Many subspecies of gaur have been described, but currently only three subspecies are recognized (see below). However, further research is required to precisely determine the taxonomy of this species.

## Distribution

Once distributed all across South-East Asia, gaur populations are now fragmented and confined to isolated areas.*Bos gaurus gaurus* occurs in India, Southern Nepal; *B. g. laosiensis* ranges in Myanmar, Laos, Vietnam, Cambodia and Southern China; and *B. g. hubbacki* in Thailand and Malaysia. The domestic form is used in the border area of Myanmar, Manipur and Nagaland.

## Discription

Adult males can reach 170 to 220 cm tall, with a body mass ranging from 600 to 1000 kg, compared with 450 to 800 kg for the cows. The domestic gaur or Mithan is different from the wild gaur by having shorter legs and males have no dorsal hump. The head is also shorter and the horns grow straight upward. Gaur subadults are chestnut with white stockinged legs. Adult gaurs are dark brown to black with white stockinged legs, and present large horns that curve inward near the tip. Gaurs are sexually dimorphic. Adult males have a pronounced muscular crest between the shoulders and a large dewlap hanging between the forelegs and a smaller one under the chin. The male horns grow out and up and have thick basal diameters. Females show slight muscular development of the neck and shoulders. In females, the horns curve inward sharply with thin basal diameters. The tip of the horn is black. Yellow hair at the base of the horns contrasts with adult dark body colour. The gaur produces a distinct smell which probably repels the insects.

## Ecology and Behavior

Gaur are found in hilly areas, below 1,800 m, covered with large tracts of forests (dry dipterocarp forest, evergreen forest, mixed-deciduous forest) and grasslands (Schaller, 1967). They use a large scope of habitats and tend to spend more time in evergreen forest and in higher elevation zones during the dry season (Prayurasiddhi, 1997). Forest edges, riverbanks, including areas with grass growth after burning are particularly utilised. Gaur tolerate well habitat degradation due to human activities and in fact may benefit from limited forest disturbance. They often forage in plantations and cultures; shifting cultivation provides openings in the canopy and increases the vegetation density of ground cover. They are both grazers and browsers; they browse more than other species of wild cattle. Bamboo shoots are one of the most frequently eaten foods in rainy season in Thailand (Prayurasiddhi, 1997). Water availability throughout the year is particularly important to support this species; and they generally do not travel more than a day’s walking distance from water (Conry, 1981). They do not wallow. Mineral licks and mineral rich springs are important requirements for this species. Home range size varies according to the sex, the season, the locality and herd size. It varies from 27 km2 to 137 km2 in Malaysia (Conry, 1989). Home range size is larger during the wet season than in the dry season, and larger herds have a larger annual home range than smaller herds. However, daily movement does not change between wet and dry seasons, and corresponds to about 3 km per day (Prayurasiddhi, 1997). The main activity period occurs during the night; during the day they stay hidden in forest or high grasses to ruminate. It is thought that such activity pattern is largely influenced by human disturbances since captive individuals are more diurnal. They live in herd of 3 to 40 individuals. Herd structure consists of adult males and females, sub-adults and calves. This structure is conserved between seasons. Individuals maintain their relative position in the herd’s dominance hierarchy by sparring (Thomas, 1996). The oldest female leads the herd to foraging locations and the dominant males play a defensive role (Prayurasiddhi, 1997). Dominance rank inside the herd is determined by individual body size (Schaller, 1967; Thomas, 1996). Gaur herds can occasionally associate with sambar deer (*Cervus unicolor*). Female are polyestrus and reproduction can occur at any time of the year, with peaks of birth depending of environmental conditions. A single calf is born after nine months of gestation. Maximum longevity in captivity is 24 years (Thomas, 1996). Calf and juvenile gaurs have several predators (*Panthera tigris; Panthera pardus; Neofelis nebulosa; Cuon alpinus; Ursus thibetanus*), but only tigers are powerful enough to kill adults.

### **Feeding Ecology**

Wild gaur graze and browse on a wider variety of plants than any other ungulate species of India, with a preference for the upper portions of plants, such as leaf blades, stems, seeds and flowers of grass species, including *kadam*.

During a survey in the Bhagwan Mahaveer Sanctuary and Mollem National Park, 32 species of plants were identified as food for gaur. They consume herbs, young shoots, flowers, fruits of elephant apple (*Dillenia* ssp.) with a high preference for leaves. Food preference varies by season. In winter and monsoon, they feed on preferably fine and fresh 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* ssp.) 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 am and between 5:30 and 6:45 pm. During the hottest hours of the day, 1:30 to 3:30 pm, 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.

### **Reproduction**

Gaur have one calf (or occasionally two) after a gestation period of about 275 days, about nine months, a few days less than domestic cattle. Calves are typically weaned after seven to 12 months. Sexual maturity occurs in the gaur's second or third year. Breeding takes place year-round, but typically peaks between December and June. The lifespan of a gaur in captivity is up to 30 years.

### **Natural Predators**

Due to their formidable size and power, gaur have few natural predators besides humans. Leopards and dhole packs occasionally attack unguarded calves or unhealthy animals; however, only the tiger and the saltwater crocodiles have been reported to kill a full-grown adult. But the habitat of gaurs and saltwater crocodiles seldom overlaps in recent times due to the decreasing range of both species, and a crocodile needs to be a grown adult (more than 3.7 m and 300 kg) to make a successful attack on healthy bulls.

Tigers hunt young or infirm gaur, but have also been reported to have killed healthy bulls weighing at least 1,000 kg (2,200 lb). A video of a tiger killing a female gaur was recorded in the Bandipur Tiger Reserve in October 2013. 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. In Nagarahole National Park, upon sensing a stalking tiger, a herd of gaur walked as a menacing phalanx towards it, forcing the tiger to retreat and abandon the hunt. Gaur are not as aggressive toward humans as wild water buffaloes.

## Conservation

The global population of gaur is estimated to be between 13,000 and 30,000 individuals, with a dramatic decline all across its range due to unprecedented growth of human population in South-East Asia. Decline factors include poaching, habitat destruction, competition for food resources and disease transmission from domestic cattle. Rinderpest has for example dramatically affected the Indian gaur population in 1968. Conservation and management plans for the gaur are implemented in Malaysia and Vietnam where scattered populations are close to extinction. *B. g. laosiensis* and *B. g. hubbacki* are particularly endangered. There has been at least a 60% reduction in the gaur population in Thailand in only 20 years (Srikosamatara and Suteethorn, 1995). Poaching to sell the horns as trophies constitutes the main cause of overexploitation of remnant populations. Subsistence hunting has apparently a small influence on the viability of the population of gaurs. *Ex situ* conservation programs are implemented for gaur in US and in Europe. However, these captive populations are too small and dangerously inbred. In 2001, a gaur was cloned in U.S., but it died within a couple of days.