This story appears in the March 2019 issue of National Geographic magazine.

The intricate web of cracks and crevices that gives African elephants their distinctive look is, in fact, an essential adaptation. The millions of micrometer-wide fractures in elephants’ skin retain mud and water after mud baths, helping the animals stay hydrated between trips to the water hole. Evaporation from the mud and water also aids temperature regulation—vital because elephants, unlike many mammals, don’t sweat. How the crevices develop has long been a mystery, but Michel Milinkovitch and his colleagues may have solved it. Their research suggests that fractures form when the growth of new skin puts stress on the brittle, outermost skin layer. The findings offer fresh insights into how elephants beat the heat.

Annie Roth contributed to this story.

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