Polluted water: It’s where sea snakes wear black | Science News

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Polluted water: It’s where sea snakes wear black

A reptile may be an evolutionary counterpart to dark moths in sooty areas

9:00am, August 14, 2017
turtle-headed sea snake

DARK MARK  This dark form of a turtle-headed sea snake is shedding its skin, and maybe some toxic trace metals along with it.

Maybe it’s more than reptile fashion. The high percentage of citified sea snakes wearing black might be a sign that pollution is an evolutionary force.

Off the coasts of Australia and New Caledonia, some turtle-headed sea snakes (Emydocephalus annulatus) sport pale bands on their dark skins. Others go all black. In 15 places surveyed, the all-black form was more likely to predominate in waters near cities, military sites or industrial zones than along reefs near less built-up coastlines, says evolutionary ecologist Rick Shine of the University of Sydney.

That trend plus some analysis of trace elements in snakes’ skin suggests that the abundant dark forms could turn out to be an example of industrial melanism, Shine and his colleagues propose August 10 in Current Biology.

The most famous example of this evolutionary phenomenon comes from a dark form of peppered moth that

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