The Northeast India has been identified as one of the world’s seven richest biodiversity areas by Myers 2000. The Northeast India represents the transitional zone between the Indian, Indo-Malayan and Indo-Chinese biogeographic regions and is the geographical ‘gateway’ for much of India’s flora and fauna. As a consequence, the area is one of the richest in biological values, high in endemism and holds a large number of rare species.

Source: http://biodiversity-mohanpai.blogspot.in/2008/10/fauna-of-northeast-india.html