Explanation:

Birhors are of short stature, long head, wavy hair and broad nose. They claim they have descended from the Sun and believe that the Kharwars, who also trace their descent from the Sun, are their brothers. Ethnologically, they are akin to the Santals, Mundas, and Hos.
Bhutia tribes usally are from Tibetan origin. They migrated to Sikkim in the 16th century. They inhabited the northern part of Sikkim where they are known as the Lachenpas and Lachungpas. In Sikkim they are called as Denzongpa which is Tibetian name of Sikkim.
Toda people are a Dravidian ethnic group who live in the Nilgiri Mountains of Tamil Nadu. Before the 18th century and British colonisation Toda coexisted locally with other ethnic communities including Kota Badaga and Kurumba in a loose caste-like society in which the Toda were the top ranking.
Lepcha are also called the Rongkup meaning the children of God and the Rong, Mútuncí Róngkup Rumkup and Rongpa are among the indigenous peoples of Sikkim, India and number between 30,000 and 50,000.