Skin Hair Skims Heat Off Elephants

ScienceDaily (Oct. 10, 2012) — Body hair in mammals is typically thought to have evolved to keep us warm in colder prehistoric times, but a new study suggests that it may do the opposite, at least in elephants. Epidermal hair may have evolved to help the animals keep cool in the hot regions they live in, according to new research published Oct 10 in the open access journal PLOS ONE by Conor Myhrvold and colleagues at Princeton University.

Though the idea that low surface densities of hair can help dissipate heat is a popular concept in engineering, the biological and evolutionary significance of sparse skin hair is not well known. The authors studied the effects of skin hair densities in Asian and African elephants on thermoregulation in these animals, and concluded that elephant skin hair significantly enhances their capacity to keep cool under different scenarios like higher daytime temperatures or less windy days.

Their research suggests that the dense body hair of furry animals helps with insulation, but as skin hair grows sparser, a tipping point is reached where, for animals such as elephants, skin hair begins to help release heat from the body rather than retain it.

Continued:  http://www.sciencedaily.com/releases/2012/10/121010172120.htm