sanctuary receiving a year to annual rainfalls of between 1,600 and 2,000 millimetres in the eastern parts of the sanctuary. Over 80 percent of the rain is brought by the southwest monsoon from the Andaman Sea. Flora and habitat types Phytogeographically the sanctuary lies at the interface between the terminal southern ridges of the eastern Himalayas and the equatorial forests of the great Sunda Shelf. As most of the sanctuary is botanically unexplored, scientific knowledge about its rich flora is sparse. montane evergreen forests cover about 15 percent of the sanctuary and occur along the mountain ridges above 1,000 metres where moisture levels are high. Seasonal or dry evergreen forests are found on about 31 percent of the area, predominantly on land lying between 800–1,000 metres elevation. Gallery evergreen forests occur along permanent watercourses, where humidity is high and the soil perpetually moist. They are often categorized under dry evergreen forests, but are particularly important to the sanctuary's fauna. Mixed deciduous forest is the most common forest type in Thung Yai, covering about 45 percent, predominantly in areas below elevation. Dry dipterocarp forest is a formation unique to mainland Southeast Asia and is found on about one percent of the area. Savanna forest and grassland covers about four percent, predominantly in the thung yai or "big field" covering about 140 km2 at the centre of the sanctuary. The remaining 4% of the area are categorized as secondary forests, fallow areas, and swidden fields in the nomination for the World Heritage Site, but include also various Bamboo forests which are not included in this classification. Fauna Like the flora, the fauna of Thung Yai provides a specific mix of species with Sundaic, Indo-Chinese, Indo-Burmese and Sino-Himalayan affinities due to the sanctuary's particular biogeographic location. The savanna forest of Thung Yai is the most complete and secure example of Southeast Asia's dry tropical forest. Among the mammal species living in Thung Yai are lar gibbon (Hylobates lar), various species of macaque (Macaca) and lutung (Trachypithecus), Indochinese tiger (Panthera tigris tigris), Indochinese leopard (Panthera pardus delacouri), clouded leopard (Neofelis nebulosa), sun bear (Helarctos malayanus) and Asian black bear (Ursus thibetanus), Malayan tapir (Tapirus indicus), Indian elephant (Elephas maximus indicus), gaur (Bos gaurus), hog deer (Cervus porcinus), sambar (Rusa unicolor), Fea's muntjac (Muntiacus feae) und Sumatran serow (Capricornis sumatraensis) as well as many bat species probably including Kitti's hog-nosed bat (Craseonycteris thonglongyai). Thung Yai