牦牛主要生活英语

The wild yak has a dense undercoat of soft, close-matted hair which is covered by generally dark brown to black outer hair. Its long, shaggy coat reaches almost to the ground. The wild yak can weigh up to 1000 kg (2200 lb) with a shoulder height of over 2 m (6.5'). It occurs in treeless uplands, including plains, hills, and mountains, from as low as 3200 m (10,500') up to the limit of vegetation at about 5400 m (18,000'). It stays in high areas with permanent snow during the warmer months of August and September, and spends the rest of the year at lower elevations. The wild yak grazes on grasses, herbs and lichens. Ordinarily it gathers in groups of 10 - 30 or more, but it may occasionally be observed in large groups of 100 - 200. The wild yak was once numerous and widespread on the entire Tibetan plateau north of the Himalayas. Currently it is found in remote areas of the Tibetan plateau and adjacent highlands, including Gansu Province, China, with a few having been observed in the Chang Chenmo Valley of Ladakh (eastern Kashmir, India). Wild yak distribution is highly clumped, with most animals in widely scattered herds, concentrated in the areas with little disturbance by humans. A survey conducted in 2003 found increasing populations of wild yak compared to previous surveys taken 10 years earlier. Uncontrolled hunting by natives and military personnel is the main reason for the wild yak's decline. Its range has been reduced by more than half during this century. Poaching remains the main current threat. The wild yak has lost most of the best alpine meadow and steppe habitat to pastoralists. Problems are also caused by habitat disturbance, hybridization and competition with domestic yaks, and disease transmitted by domestic yaks.