Scientists have discovered that the turtle-headed seasnake, which usually sports bright coloured markings of yellow or white bands, turns to grey or black when living near people.
The colour differences, from those snakes living on pristine reefs to those near human habitation, are said to be caused by pollution.
A study in the journal Current Biology says the blacker skin of urban seasnakes allows them to more effectively bind and rid their bodies of contaminants, including arsenic and zinc, each time they shed their skins.
The findings add seasnakes to a growing list of species showing industrial melanism, a greater prevalence of dark-colored varieties in industrial areas.
“The animals I study continue to astonish me,” says Rick Shine at the University of Sydney. “I think it’s remarkable to find industrial melanism in organisms as different as moths and seasnakes.”
Shine says that the findings are yet another example of rapid adaptive evolutionary change in action.
“Even on an apparently pristine coral reef, human activities can pose very real problems for the animals that live there,” he says.
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