derekmead (2466858) writes "A new paper from Conor Myhrvold, Howard Stone, and Elie Bou-Zeid of Princeton, published in PLoS One, shows that elephants’ sparse hair actually acts as pin-shaped cooling fins, which helps the giant animals dissipate heat more effectively. The hair works by creating more area for heat to be released, while also also pushing heat away from the animal’s body where wind flow is less impeded.
The team calculated the heat transfer coefficients for measured values of elephants’ smooth skin (around ears, for example) and rough skin (on the legs), both with and without hair. They found that, at high wind speeds, the convection effect of the wind overpowered any surface differences. But at low wind speeds, when convection effects are lower and elephants have more trouble shedding heat, the team found that hair acted as pin-shaped cooling fins, which increased convection cooling efficiency by as much as 24 percent. For elephants dealing with huge thermal loads, that’s an important difference."
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