Discover Why Sea Snakes Often Die of Thirst While Surrounded By Water

Yellow-bellied sea snake washed up on the beach
© John Fader/

Written by Cindy Rasmussen

Updated: October 13, 2022

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Sea snakes is a group of snakes that live entirely in the ocean. They eat, swim and have their young all in the water without coming on land. As with most animal species there are some exceptions, like the sea kraits who come on land to lay eggs, but the majority of the sea snake species are surrounded by water their whole life so how could they possibly die of thirst? Lot’s of animals live in the ocean exclusively like sharks, dolphins and tuna and they don’t seem to die of thirst. Let’s find out why sea snake often die of thirst while surrounded by water.

What are sea snakes?

Banded Sea Snake swimming underwater on coral reef

Sea snakes live in the ocean and can swim like other marine animals. They have a paddle-like tail to help get around.

©Rich Carey/

Sea snakes are marine snakes that belong to the elapidae family (same as cobras, mambas and taipans) and includes two subfamilies Hydrophiinae (majority of sea snakes) and Laticaudinae ( 3 kinds of sea kraits). Sea snakes live in the ocean, they swim all the time and can dive deep underwater to find food or escape prey. They are also highly venomous! Cobras, mambas and taipans are some of the most venomous land snakes and sea snakes are even more venomous than their land cousins.

Sea snakes are well adapted for aquatic life and even have a paddle-like tail to help propel them through the water. Most are around 4-5 feet long and small-medium bodied. The 69+ species include a variety of colorations including the yellow-bellied sea snake which is all black on the back and has a bright yellow belly and the banded sea snakes which are a variety of base colors with vertical bands.

Do sea snakes need water to live?

Yes! All living things need water to survive. Animals need food and water to produce energy and to stay hydrated. Sea snakes are no different; they require water to stay hydrate to live.

Do sea snakes drink ocean water?

Scientists used to think that sea snakes drank ocean water (sea water) but a recent study suggests that they need freshwater to survive.

Why do sea snakes often die of thirst while surrounded by water?

Sea snakes need freshwater to survive, so although they are surrounded by water they can die of thirst.

©Richard Whitcombe/

Sea snakes can die of thirst during times of drought when there is no or little rainfall over the ocean. Researchers at the University of Florida performed a study on sea snakes that found that sea snakes need freshwater to survive vs. sea water. So even though they are surrounded by water if they don’t have access to freshwater they can die of thirst. Some marine animals like bony fish (tuna, herring) can drink saltwater and have a special gland that processes the salt. Sharks process salt water through their gills and skin. So they don’t really “drink” water but they do maintain the correct hydration.

The Researchers from Florida found that the sea snakes drink freshwater that pools on top of the ocean after rainfalls. The researchers called these pools “oceanic freshwater lenses”. The sea snakes skim along the surface of the water and drink the freshwater.

What kind of sea snakes were part of the study?

A yellow-bellied sea snake on rocks

Yellow-bellied sea snakes are all black with a bright yellow belly. their paddle-like tails are pale yellow with black splotches.

©Ken Griffiths/

The researchers were studying the Yellow-bellied sea snake (Hydrophis platurus). These sea snake have a distinctive look, they are jet black on their backs and have a bright yellow belly. Their paddle-like tail is a pale yellow with black splotches. Yellow-bellied sea snakes can get to be around 4 feet long. They spend 90% of their lives underwater, only coming to the surface to breathe air.  These snakes are known to be the most widely ranging snakes and can be found in the Indian and Pacific Oceans. On rare occasions a Yellow-bellied sea snake has washed up on shore in southern California so it is believed that they do live as far north as southern California, but again, they live far from shore out in the middle of the ocean.

Have a lot of sea snakes died of thirst in the past few years?

Last year in New Zealand multiple reports of Yellow-bellied sea snakes washing up on shore alerted the attention of researchers. In May of 2021 an 11-year-old found one on Northland beach and carried it into town to find a box for it. He had no idea he was handling an extremely venomous snake. Luckily for the boy the snake died on its way home so no one was injured. New Zealand is one of the areas in the world where there are no snakes. So there is also no need for antivenom. So when more of these snakes started washing up on shore local authorities started to get concerned. The belief is, as the oceans warm due to climate change, the range of these snakes will expand and will include areas where they have not lived before.

Where else have sea snake been spotted?

A research article in the Journal of Climate Change and Human Health suggests that climate change is responsible for the expansion of the sea snake habitat. They have been located in areas where they have never been seen before like South Korea, Japan and southern California. The increase in water temperatures and the expansion of the sea snakes habitat could increase the human-animal conflicts which is worrisome due to the toxic levels of the sea snakes.

What other venomous animals live in the ocean?

Deadliest Jellyfish - Box Jellyfish



are another venomous marine animal.

©Nuttawut Uttamaharad/

 The research on sea snakes and climate change also looked at a variety of other venomous marine animals that may be affected. The list includes:

Kind of makes you want to stay on shore!

Could there be mass deaths of sea snakes if there was a long drought over a portion of the ocean?

Yes, there could be. Researchers are trying to study the effects of climate change and drought at sea and on land. The study conducted by the University of Florida researchers was performed after 6 months of seasonal drought off the coast of Costa Rica. Since the sea snake seems to have such a wide distribution it would seem they are pretty adaptable and can move to areas that have more rainfall if needed. But introducing a new species to any new ecosystem has its risks as they can become invasive species and compete for food and resources. More research needs to be done to ensure that their current ecosystems are protected.

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About the Author

I'm a Wildlife Conservation Author and Journalist, raising awareness about conservation by teaching others about the amazing animals we share the planet with. I graduated from the University of Minnesota-Morris with a degree in Elementary Education and I am a former teacher. When I am not writing I love going to my kids' soccer games, watching movies, taking on DIY projects and running with our giant Labradoodle "Tango".

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