Why elephants don’t shed their skin
The African elephant is known for its thick, wrinkly skin. But look closer and you’ll see an intricate network of tiny crevices that makes the mighty mammal’s hide resemble cracked mud or damaged asphalt.
The purpose of those cracks is no mystery. An elephant doesn’t have sweat or sebum glands, so it covers its skin in water or mud to keep cool. The micrometer-wide cracks in its skin retain 10 times more moisture than a flat surface, helping the animal regulate its body temperature. They also help mud adhere to the skin, which protects against parasites and rays from the sun.
Now, a team of researchers believe they have discovered that these cracks form as a result of the stress of skin bending, not shrinking. Their explanation, published recently in Nature Communications, might even hold clues to treating a common human genetic skin disorder.
Michel Milinkovitch, an evolutionary biologist at the University of Geneva in Switzerland, and his team found that dead elephant skin cells resemble those of humans suffering from ichthyosis vulgaris, a disease found in 1 of every 250 people that prevents the shedding of skin. In humans, the condition, for which there is no cure, causes thick, dry scales on the surface of the skin that are usually treated with moisturizers.
But in African elephants, holding onto all that dead skin appears to be beneficial: The lack of shedding causes the skin to build up as the elephant ages, eventually bending and breaking over the layer of papillae, which provides the animal the means to stay cool.
More research is needed to determine whether the lack of skin shedding in elephants shares a genetic basis with ichthyosis vulgaris in humans. But the confluence of the conditions could suggest a path forward for treating the ailment.