As they are surrounded by undrinkable water, living in the sea is hardly an advantage for sea snakes when it comes to quenching their thirst.
These snakes wait for the rainy days or find places where it is raining and wait for pool of fresh water to form on the surface, and then drink, finds a new study.
The researchers studied the yellow-bellied sea snake, a venomous animal.
Most of these snakes probably never leave the ocean as they generally live in the open sea, far from any land. They are also the most widely distributed reptile in the world.
"When you have a good rain storm, there's a lot of fresh water falling on the ocean surface. It's less dense than sea water so it tends to float" said Harvey Lillywhite of University of Florida.
Scientists call the pool of fresh water that forms on the surface "lenses".
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"How big the lens is, how pure it is, and how long it lasts, depends on how much rainfall there is and the nature of the mixing conditions at the time, driven by wind, and other factors," Lillywhite said.
If it is raining or just rained, the water would be pure, he said.
The snakes come up from below and drink from the collecting lenses.
They do not have to do the exercise very often, sometimes going six or seven months without a drink, LiveScience reported.
The study was published in the Proceedings of the Royal Society in England.