The Great Nicobar Biosphere Reserve encompasses a large part (some 85%) of the island of Great Nicobar, the largest of the Nicobar Islands in the Indian Union Territory of Andaman and Nicobar Islands. The Nicobars lie in the Bay of Bengal, eastern Indian Ocean. It was included in the list of Man and Biosphere program of UNESCO to promote sustainable development based on local community effort and sound science.
The reserve is home to many species of plants and animals, often endemic to the Andaman and Nicobars biogeographic region. Species of fauna in the reserve include: Nicobar scrubfowl (Megapodius nicobariensis, a megapode bird), the edible-nest swiftlet (Aerodramus fuciphagus), the Nicobar long-tailed macaque (Macaca fascicularis umbrosa), saltwater crocodile (Crocodylus porosus), Andaman water monitor (Varanus salvator andamanensis), giant leatherback sea turtle (Dermochelys coriacea), Malayan box turtle, Nicobar tree shrew, reticulated python (Python reticulatus) and the giant robber crab (or coconut crab, Birgus latro).