of descendents, and consequently, in larger group size. Thus, energetic
factors are interconnectedwith social factors (see below),
since the use and control of fire has been related with sexual division
of labor and novel implications for the regulation of social
behavior (Wrangham et al., 1999), and also with thermoregulatory
factors (see below), since larger group size is expected to increase
ectoparasitic load, which may favor the loss of body hair
(Rantala, 2007).