University of Exeter researchers studied green turtles nesting on Ascension Island, a British overseas territory in the South Atlantic Ocean.
They found that eggs laid by turtles nesting on a naturally hot beach were able withstand high temperatures better than eggs from turtles nesting on a cooler beach just a few miles away, a university release said Monday.
A darker sand makes the warm beach 3 to 5 degrees Fahrenheit hotter than a nearby beach with white sand, researchers said.
"We believe this is the first time that adaptation to local environmental conditions has been demonstrated in sea turtles, which is all the more remarkable because the beaches in question are just 6 kilometres [3.7 miles] apart," research leader Jonathan Blount said.
Most female turtles nest on the same beaches where they themselves hatched, so populations can adapt to specific nesting locations and conditions, the researchers said.