Elephant "Hair Conditioning"

Hair on an Asian elephant (right) compared to an African elephant's head (left). Image taken by: Conor Myhrvold

Researchers think that the hair on an elephant might actually function to keep the animals cool as opposed to keeping them warm as it does for other mammals. Living in hot climates (as high as 122 degrees F) since the last ice age means the animals have had to evolve ways to tolerate the heat. Until now, it was only known that elephants kept cool by dissipating heat from their ears (circulating warm blood to their large flat ears, where the heat could escape, and returning the cooled blood to the general circulation), bathing in water, using dust to help block the sun, moving to shaded areas, or spraying water or mud over their bodies. What little hair elephants had was thought to be either left over from colder times or to serve a sensory role.

To study "hair conditioning", Dr. Bou-Zeid and his team calculated the flow of heat from a surface with varying wind speeds, skin textures, and densities of hairs that were similar in diameter and length as those found on an elephant. Their research showed that elephant hairs could improve heat loss by 5-20%, depending on the chosen wind speed. They think that the animal's body heat is able to escape through the hairs kind of like electricity through a wire. This research is the first to show that animal hair has the potential to cool and animal down when the hair cover is sparse, like an elephant's, as opposed to dense.

Source:

Myhrvold CL, Stone HA, Bou-Zeid E (2012) What Is the Use of Elephant Hair? PLoS ONE 7(10): e47018. doi:10.1371/journal.pone