Rivers had already formed a career in physiology and psychology. But now he moved more definitively into anthropology. He wanted a demographically small, fairly isolated people, comparable to the island societies of the Torres Strait, where he might be able to get genealogical data on each and every individual. The Todas in the Nilgiri Hills of Southern India, with their population then about 700 plus, suited Rivers's criteria. And they had specific features of social organization, such as polyandrous marriage and a bifurcation of their society into so-called moieties that had interested historical evolutionists. Whether his fieldwork was initially so single-minded is questionable, however, since at first Rivers looked at other local communities and studied their visual perception before fixing all his attention on the Todas.
