Snakes' Skins Adapated to Deter Water Loss

Snakes, like all animals that live in arid climates, have evolved ways to conserve water and prevent dehydration. Now, scientists can explain how snakes' waterproof skins serve as effective moisture barriers. Although scientists have long believed that reptilian skin was somehow adapted to foster water conservation, they did not understand the underlying physiology until the 1970's. It was then that Harvey Lillywhite and collegues set about to measure the evaporation rates from snakes' skins. The researchers examined evaporation rates for recently-hatched California king snakes. They also recorded evaporation rates for the snakes shortly after they had shed their skin for the first time.

Lillywhite and colleages found that the post-shedding evaporation rate fell to half of that measured before shedding. Eager to find a reason for such a drastic difference in evaporation rates, the team analyzed samples of both skin types, pre- and post-shedding. They found that a layer in the skin known as the keratin/lipid barrier had doubled in thickness after the first skin shedding.

Now that Lillywhite and his colleagues understand how water evaporation is minimized through the snakes' skins, they are investigating the maternal behavior of snakes to try to determine if it is yet another adaptation to aid water conservation. The researchers observed that although snakes tend not to be overly protective of their young, often abandonning them at birth, some species do tend their young until they have shed their skin for the first time. Lillywhite observes that some snakes curl around their young, protecting them until the family later disperses. He believe that this behavior helps to prevent the young from becoming dehydrated in the vulnerable time before their first ecdysis (skin shedding).

Find out more: Phillips K. Sealing Snake Skin. The Journal of Experimental Biology. 205:ii (2002).

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