Skin hair skims heat off elephants
20 October ScienceDaily
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.
According to the authors, elephants have the greatest need for such
heat loss to maintain a constant body temperature, since they are large
terrestrial mammals that live in hot climates. Their results are the
first to suggest that animal hairs could play a role in heat dissipation
that could be beneficial to certain animals, like elephants.
Elie Bou-Zeid, corresponding author on the study, says "Sparse hair
increases heat dissipation from the skin of elephants and help the
largest terrestrial mammal meet its thermoregulation needs." |