Brachyskelic:
Brachyskelic individuals have a sitting height between 49 and 51 percent of their overall height. Brachyskelia is widespread in the tropics but appears to be rare in cold regions. This trait is a response to heat where sweating is efficient, so that bodies with a higher surface have an advantage (Allen's rule). Most Sub-Saharan Africans show brachyskelia, except for the forest populations and Khoisanids. Several Saharan populations (Tuareg) show brachyskelic proportions as well. Outside of Africa it is common in India, New Guinea, and Australia. Brachyskelia hardly developed in the American tropics, because they were only inhabited since the late Paleolithic when humans faced different selective pressures, thus trunk length can be seen as a primary adaption.