All about Gaur (Bos gaurus)

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Habitat and Ecology [top] Habitat and Ecology: The Gaur occurs from sea level up to at least 2,800 m asl (Wood 1937; Wharton 1968; Choudhury 2002). Despite the many reports that call it an animal of hill-country, low-lying areas seem to comprise optimal habitat (Choudhury 2002): in Conry’s (1989) study area, elevations ranged from 46 to 1,079 m asl but the three radio-tracked Gaur only used areas below 381 m. Elevations below 61 m were used most intensively and all three animals selected these low-lying areas; elevations above 61 m were selected against or used in proportion to availability (Conry 1989). Similarly, in the Tenasserim–Dawna mountains, Thailand, signs of Gaur were more abundant in the lowlands than in the hills, noting that this was the opposite of the patterns that would be predicted if hunting (itself concentrated heavily in the lowlands) was the chief determinant of population densities, although solitary animals were found mainly in the hills (Steinmetz et al. 2008). Schaller (1967) compared vegetation maps of India with the (mid-20th century) distribution of Gaur and concluded that the species was largely confined to evergreen, semi-evergreen, and moist deciduous forest but it also occurred in dry deciduous forest areas at the periphery of its range. He considered Gaur habitat to be "characterized by (1) large, relatively undisturbed forest tracts, (2) hilly terrain below an altitude of 5,000 to 6,000 ft (1,500–1,800 m asl), (3) availability of water, and (4) an abundance of forage in the form of coarse grasses (including bamboo), shrubs, and trees". However, He cautioned that the apparent preference of Gaur 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. Similarly, Wharton (1968) concluded that Gaur appeared to avoid evergreen rainforest, "preferring foothill tracts of sub-humid or deciduous forest adjacent to savanna forest, glades or other open terrain affected by man and fire thus co-existing with and exploiting low human populations in hill zones with moderate to heavy rainfall". Throughout the range of Gaur, habitat destruction and human presence is usually higher in lowlands than in hills, meaning that differential human pressures may have caused the apparent preference of Gaur for hills. Gaur occurs in many forest types in Lao PDR, Viet Nam and Cambodia including truly evergreen and montane forest, but populations in closed canopy forests especially those at higher elevations might naturally be at much lower densities than those in lowland areas with a mosaic of open and closed forest types, and in closed canopy forests areas the species appears to frequent grassy openings (Duckworth et al 1999; Greiser Johns 2000; Duckworth and Hedges 1998; Timmins and Ou 2001; R.J. Timmins pers. comm. 2008). No significant difference was found in Gaur densities in moist compared with in dry deciduous forests in Nagarahole, India (Karanth and Sunquist 1992). Steinmetz et al. (in prep.) considered that Gaur herds in an expanding population were consistently concentrated in mixed deciduous forest rather than semi-evergreen forest, although the total area of study, that was safe from poaching, was only 20 km².

Gaur can persist in fragmented areas with some habitat disturbance and hunting, including in landscapes dominated by plantations (such as on parts of the Valparai plateau, south India), but in Southeast Asia it has been too heavily hunted in such areas to survive in them. Gaur can better tolerate rugged terrain and denser forest than other wild and domestic cattle, provided that there are adequate water sources (N.S. Kumar pers. comm. 2008.; Smith and Xie Yan in press). In Thailand it uses former cultivation amid forest, and populations in such areas can recover well if not hunted (Anak Pattanavipool pers. comm. 2006; R. Steinmetz pers. comm. 2006). A study of coffee estates around Bhadra Wildlife Sanctuary, India, recorded Gaur only in those coffee areas within 1 km of the sanctuary’s boundary (Bali et al. 2007).

Gaur both grazes and browses, reportedly eating mostly young green grasses but also leaves, fruit, twigs, and bark of various woody species, as well as coarse dry grasses, and bamboo. It seems able to maintain good condition on relatively low quality feed. At least 180–190 species of plants have been recorded in the diet (N.S. Kumar pers. comm. 2008). More information is given about Gaur’s diet in Dunbar Brander (1923), Hubback (1937), Schaller (1967), Wharton (1968), Krishnan (1972), Khan (1973), Conry (1981), Ebil Yusof (1982), Ramachandran et al. (1986), Prayurasiddhi and Smith (1993) and Sankar et al. (2000). Captive Gaur are reported to eat about 20 kg of green fodder per day (Ramachandran et al. 1986). During the cool season (November–February) the Gaur that Schaller (1967) studied in central India ate various herbs, large quantities of the leaves and seeds of bamboo, various other grasses, and the leaves of a number of tree species; but by the beginning of the hot season (March–June) coarse dry and semi-dry grasses made up the bulk of their diet, averaging 85% by volume (range 66–100%; four rumen samples), with browse only making up about 10%. Gaur also feeds on crops including corn, cassava, and young rubber trees, sometimes causing great damage (Wharton 1968; National Research Council 1983). Schaller (1967) reported that Gaur in Kanha National Park drank at least once per day during the hot season, usually in the evening. Sahai (1972) stated that Gaur drink at least twice in a 24-hour period but there appears to be no fixed time for drinking.

In undisturbed areas, Gaur is mainly diurnal, but in areas of high human disturbance, it is reported to become mainly nocturnal.

The basic social group appears to be a female–juvenile unit with larger groups tending to be more-or-less temporary assemblages (as in the other large species of Asian Bovini). Maternal herds containing several adult cows, juveniles, and calves frequently occur but their composition is somewhat fluid, particularly during the rut; these herds can often contain several subadult and adult males. The number of bulls in a herd changes with the time of year. Mature males associate with cows primarily during the rut: during Schaller’s study in Kanha National Park 65% of herds were accompanied by a mature male during April (the peak of the rut) but during the second half of the year the proportion dropped to 31% (Schaller 1967). Neither Schaller (1967) nor Sahai (1972) found any evidence to support Powell’s (1964) statement that young bulls usually live apart from the maternal herds; nor did Schaller’s observations support Dunbar Brander’s (1923) statement that the ‘master bull’ drives all other males from the herd. Males not associating with mixed herds either live in all-male groups or are solitary. The bull herds are generally unstable, although sometimes two or more animals may frequently associate. The typical herd size appears to be in the range of 5–12 animals and herds are rarely larger than 20 (Dunbar Brander 1923; Hubback 1937; Hislop 1961a; Schaller 1967; Prater 1971; Sahai 1972; Pal and Guin 1986). Large groups of 20, 40, or even 100 animals are probably temporary aggregations of smaller groups (Pal and Guin 1986).

The majority of the 125–150 Gaur studied by Schaller (1967) in Kanha National Park (India) ranged over an area of at least 78 km²; and the herds he studied travelled on average 2–3 miles (3.2–4.8 km) a day, although on occasion the distance could be much less. In West Malaysia Gaur home ranges have been estimated to be: approximately 13 km² (the Kuala Tahan herd in Taman Negara National Park) (Weigum 1972); and 29.9 km² for a yearling male, 52.1 km² for a yearling female, and 137.3 km² for an adult male in Pahang (Conry 1989). The large differences between the two studies probably reflect the different methods employed by the two workers (see Conry 1989: 60). Home ranges that can be as large as 137 km² hinder the setting aside of conservation areas for Gaur, particularly as Gaur often occurs in those areas where the pressures for economic development are highest.

In central India, most Gaur mate in December and January, and calves are born in August and September according to Dunbar Brander (1923); Stebbing (1911) and Sanderson (1912) generally agreed with Dunbar Brander but noted that calves may also be born in April, May, and June. In Kanha National Park (central India) Schaller (1967) recorded rutting bulls from December to June, with an apparent peak of sexual behaviour in March and April; however, the occurrence of a few new-born animals throughout the year indicated that some mating must occur in every month. In southern India the majority of matings reportedly take place between November and March (Morris 1937). In Cambodia the majority of Gaur births occur in December and January (Wharton 1957). In Myanmar, calves are born throughout the year (Evans 1912; Peacock 1933); and in West Malaysia young Gaur are seen in all months except October to December (Hubback 1937).

The gestation period of Gaur is reported to be nine months by Hubback (1937) and Crandall (1964) and 270 days, ‘a little shorter than for Banteng or domestic cattle and longer than for yak and Kouprey’, by National Research Council (1983: 49). Only one calf is born to a cow per pregnancy; there are no records of twins (Hubback 1937; Schaller 1967). Females probably first mate when about two years old and thus have their first calf at three years old (Schaller 1967). If the food supply is favourable, most adult females probably calve every year. In Kanha National Park, approximately 90% of adult cows bore young during a year but calf mortality was high, with about 50% of the calves dying before reaching one year old; the main cause of death was predation by Tigers Panthera tigris (Schaller 1967).

Rarely, bulls kill each other when fighting, and occasionally they are severely injured while fighting. Predation is by far the major cause of Gaur mortality, perhaps followed by disease (N.S. Kumar pers. comm. 2008). For example in Bandipur, Gaur is the most important prey in terms of the biomass taken by Tiger (42%) and Leopard Panthera pardus (15%) (Andheria et al. 2007). In Bandipur, Gaur remains were found in about 24% of Tiger faeces and 9% of Leopard faeces (Andheria et al. 2007). In adjoining Nagarahole, the proportion of Gaur in Tiger’s diet was about 45% in kills, 17% in scats (Karanth and Sunquist 1995). In Tadoba-Andhari, Gaur together with Sambar contributed to nearly 70% of the prey biomass consumed by Tiger, whereas in Pench-Maharashtra it was 80% (Karanth and Kumar 2005). In well protected forest reserves where different body-sized ungulates are abundantly available, Gaur is selectively predated by Tiger (N.S. Kumar pers. comm. 2008).
Systems: Terrestrial
 

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