Shaved asian paipan

Description:Fur could have evolved from sensory hair whiskers. Hairs can sense movements of air as well as touch by physical objects and they provide sensory awareness of the presence of ectoparasites. There is no evidence that sexual selection would proceed to such a drastic extent over a million years ago when a full, lush coat of hair would most likely indicate health and would therefore be more likely to be selected for, not against, and not all human populations today have sexual dimorphism in body hair. Horses and humans are two of the few animals capable of sweating on most of their body, yet horses are larger and still have fully developed fur. Instead, the relatively sparse density of Afro-hair, combined with its springy coils actually results in an airy, almost sponge-like structure that in turn, Jablonski argues, [47] more likely facilitates an increase in the circulation of cool air onto the scalp. Some modern mammals have a special gland in front of each orbit used to preen the fur, called the harderian gland. In this sense, the trait may enhance comfort levels in intense equatorial climates more than straight hair which, on the other hand, tends to naturally fall over the ears and neck to a degree that provides slightly enhanced comfort levels in cold climates relative to tightly coiled hair.

Views: 8949 Date: 2018-12-29 Favorited: 49