Cracks in skin help elephants keep cool

Oct. 3 (UPI) -- Elephants' skin is marked by a network of tiny crevices. These tiny channels trap water and mud, helping elephants regulate their body temperatures.

In a new paper, published this week in the journal Nature Communications, scientists confirmed the channels are fractures of the animal's outer skin layer.

Researchers at the University of Geneva, in Switzerland, conducted a detailed analysis of elephants' skin structure. The findings showed the dry, outer layer of an elephant's skin grows in a way that encourages tiny cracking caused by mechanical stress.

Elephants don't have sweat glands. As a result, the outer layer of dying skin cells becomes dry and brittle. The cracks that form, however, come in handy.

When sweat evaporates, it helps cool the body. To replicate this process, elephants take frequent water and mud baths, coating their body in a layer of moisture. The tiny cracks aid the process.

Scientists determined the intricate network of crevices prevents mud from easily flaking off and helps elephants retain up to 10 times more water than a smooth surface.

A large concentration of keratin, a tough, resistant protein, in the outer layer of elephants' skin encourages cracking. The outer layer's structure, a lattice of tiny elevations, further enhances cracking.

Stress is placed on the outer skin layer as elephants replenish their epidermis with new cells, thickening the skin's base layer. Because elephants don't efficiently shed their dying outer layer of skin cells, the crack-inducing tension between the outer and inner skin layers is enhanced.

Researchers likened cracking elephant skin to the skin of humans affected by ichthyosis vulgaris, a genetic disorder that disrupts a person's ability to naturally shed dead skin cells. Humans affected by ichthyosis vulgaris often experience dry, scaly skin.

Further study is needed to determine whether similar biomechanics are involved.

"This correspondence would also demonstrate that similar mutations that occurred independently in the evolutionary lineages of humans and elephants turned out to be unfavorable in the former and adaptive in the latter," researcher Michel Milinkovitch said in a news release.