Contrary to what scientists earlier believed, sea snakes can't actually drink salt water and instead sometimes wait for months at a time for the next rainfall.

A University of Florida biologist and a research team conducted experiments and did field studies with the yellow-bellied sea snake over a three-year period, discovering that the snakes only drank when fresh water was available, said a school news release.

"These snakes refuse to drink salt water, even when dehydrated," biology professor Harvey Lillywhite said in the news release. "They need fresh water to survive."

Scientists had believed that all marine vertebrates had evolved to be able to exist on salt water. Despite what current physiology textbooks say, "no sea snake we have tested drinks sea water," Lillywhite said.

Studying snakes in Guanacaste, Costa Rica, the researchers learned that the reptiles can go for as long as six or seven months without drinking water during the area's dry season.

Dehydrating slowly, the snakes can lose around 25 percent of their body mass. They sometimes consume the same amount of body mass in fresh water when it is available.

The creatures get their water from rainfall, which is less dense than sea water and forms into a "lens" on the ocean surface. According to the research from Lillywhite and his team, the snakes seem to sense when it will rain so they can head to the surface for fresh water.

"We think they almost certainly know that it rains because their behavior changes during the approach of a tropical storm as the atmospheric pressure changes," Lillywhite said in the news release.

The yellow-bellied sea snake is the only species of its kind to live in the open ocean, according to National Geographic. The black and yellow creature hunts at sea and also gives birth to live young in the open ocean.

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