Mesorrhine noses show an average width to length ratio. Unlike for several other anthropometric traits, for the nasal index, the average category is barely more frequent than the other categories. In Africa, mesorrhine groups are mostly found in a long contact belt between Caucasoid desert groups and Sub-Saharan groups. Mesorrhiny sporadically appears in Siberia, and is common in tribals of India. It dominates in all of South East Asia except for some Indochinese mountain groups and people of the interior of Borneo. Mesorrhiny is typical for Polynesians as well, and the most common nasal index in all of tropical Native America.