Assam is one of the richest biodiversity zones in the world and consists of tropical rainforests,deciduous forests, riverine grasslands, bamboo orchards and numerous wetland ecosystems; Many are now protected as national parks and reserved forests.
Assam has wildlife sanctuaries, the most prominent of which are two UNESCO World Heritage sites the Kaziranga National Park, on the bank of the Brahmaputra River, and the Manas Wildlife Sanctuary, near the border with Bhutan. The Kaziranga is refuges for the fast-disappearing Indian one-horned rhinoceros. The state is the last refuge for numerous other endangered and threatened species including the White-winged Wood Duck or Deohanh, Bengal Florican, Black-breasted Parrotbill, Red-headed vulture, White-rumped vulture, Greater Adjutant, Jerdon's Babbler, Rufous-necked hornbill, Bengal tiger, Asian elephant, Pygmy hog, Gaur, Wild water buffalo, Indian hog deer, Hoolock gibbon, Golden Langur, Capped langur, Barasingha,Ganges river dolphin, Barca snakehead, Ganges shark, Burmese python, Brahminy river turtle, Black pond turtle, Asian forest tortoise, and Assam roofed turtle. Threatened species that are extinct in Assam include the Gharial, a critically endangered fish-eating crocodilian, and the Pink-headed duck (which may be extinct worldwide). For the State Bird, the White-winged Wood Duck, Assam is a globally important area.
