What Do Sea Snakes Eat?

Sea Snake Up Close
© Jack Pokoj/Shutterstock.com

Written by Colby Maxwell

Updated: February 8, 2023

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Sea snakes are quite possibly the oldest living species of snake on earth. Despite their age, we know less about them than many other types of snakes, mostly because of the difficulty of viewing them in their habitat. Still, these amazing reptiles are a diverse and interesting group that most people don’t know much about. Today, we are going to learn all about the diets of these aquatic snakes, plus a little about how they hunt. Let’s discover, What Do Sea Snakes Eat?

What do sea snakes eat?

Sea Snake in Coral

All sea snakes are carnivores that mostly eat eels. They also eat small fish, crustaceans, and eggs.

©Oksana Golubeva/Shutterstock.com

Sea snakes primarily eat eels, fish, and small crustaceans.

There are dozens of species of sea snake, all with a diet that reflects their particular ecological niche. Still, there are some similarities between them all that we can explore. Regardless of if they live in a muddy mangrove or in a vibrant coral reef, sea snakes generally prefer the same things.

The most preferred foods by sea snakes are eels. A report in 1983 has data to confirm that the most common food that sea snakes prefer is eels. The data was acquired by catching sea snakes and recording what was found inside their belly. What researchers learned was that one of the main factors for sea snakes when choosing their prey is their ability to swallow it! Since they are thin and long, it makes sense that eels would be the perfect food for these reptiles.

Although eels are the primary food source for sea snakes, they aren’t the only ones. Fish is another essential source of food for sea snakes, but they generally prefer a specific shape of fish. The same report showed that the most common type of fish was a goby-like fish. Most goby-like fish are round and have long, tapered bodies that could be easily swallowed by a sea snake. Additionally, sea snakes eat pretty much any fish they have the ability to wrap their mouths around.

Although not as common, sea snakes have the ability to eat all sorts of other prey. Some common prey sources include small octopus, fish eggs, small crustaceans, and soft-shelled crabs.

A complete list of foods sea snakes eat:

Here is a complete list of the foods sea snakes eat:

  • eels
  • goby fish
  • mullet
  • puffers
  • rabbitfish
  • surgeonfish
  • mudskippers
  • flatfish
  • small octopus
  • fish eggs
  • small crustaceans
  • soft-shelled crabs

Sea snakes are carnivores that primarily prey on eels, although they do eat fish and crustaceans.

How do sea snakes hunt?

What Do Sea Snakes Eat?

Sea snakes hunt using their highly potent venom to kill prey.

©Jack Pokoj/Shutterstock.com

Sea snakes are aquatic snakes that can’t actually move on land. As a result, all of their hunting happens in the water. Let’s take a look at some of the strategies they use to help them hunt.

Part of what allows sea snakes to be so successful is their venom. Sea snakes are among the most venomous snakes in the world. The closest related group of terrestrial snakes are cobras. Cobras are known for their venom, but the sea snake is known to be multiple times more venomous than even the cobra. The hook-nosed sea snake is the most venomous of all sea snakes, with an estimated 3% of bites resulting in death. For hunting aquatic life, this venom allows the snake to kill prey without too much of a struggle.

Although sea snakes spend their entire lives in the water, they need to surface to breathe. An adaptation they have are lungs that spend the entire length of their body and skin that can absorb oxygen from the air. Both of these traits allow them to dive quite deep in order to look for food in hard-to-reach places.

What is the largest prey that a sea snake can hunt?

Hook Nosed Sea Snake ArossimBeach Goa India

Sea snakes can eat prey up to 1.2 times the width of their neck.

©Vikramonice / CC BY-SA 4.0, via Wikimedia Commons – Original / License

Although sea snakes can kill almost anything they can bite, they have to be able to swallow it. In a study in 2013, researchers recorded a correlation between the neck diameter and prey size that was around 1.2. Essentially, a sea snake is able to eat prey that is up to 1.2 times larger than its neck. Anything more and it would cause it to choke.

For prey that is larger, the most common tactic is to pull off pieces to swallow. There have been recorded instances of snakes pulling apart living soft-shelled crabs during the molting season. Although a snake couldn’t swallow a large crab with a tough shell, they are able to tear it apart during the molting season and swallow parts of it at a time.

All prey items were ingested head first. There was a positive correlation between snake SVL and total length of prey, but large snakes also ate small prey. Snake neck diameter was correlated positively with maximum prey diameter, and snakes did not consume prey items with a maximum diameter more than 1.2 times their neck diameter, a characteristic that may indicate gape limitation.

Feeding Habits of the Annulated Sea Snake

Do sea snakes ever hunt on land?

What Do Sea Snakes Eat?

All “true” sea snakes are totally aquatic, but other groups of sea snakes do occasionally go on land to breed.

©Richard Whitcombe/Shutterstock.com

True ea snakes are totally adapted to hunting in the water. They are round and have flattened tails for swimming, unlike terrestrial snakes. Although some sea snakes get stranded in tidepools, most species spend their lives in water that is up to 100 meters deep.

There are some groups of sea snakes, known as laticaudids, homalopsids, and natricids that aren’t totally adapted to the water. Many of these snake species must return to land in order to breed and lay eggs. True sea snakes (hydrophiids) spend their lives totally in the water, however.

What sea snakes live in the United States?

What Do Sea Snakes Eat?

The yellow-bellied sea snake is the only sea snake seen in the United States.

©Ken Griffiths/Shutterstock.com

Thankfully, most Americans don’t have to worry about sea snakes. The only state that has ever had a sea snake sighting is Hawaii and sightings are quite rare. Yellow-bellied sea snakes are open-water snakes and have only been sighted in Hawaii 20 times.

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About the Author

Colby is a writer at A-Z Animals primarily covering outdoors, unique animal stories, and science news. Colby has been writing about science news and animals for five years and holds a bachelor's degree from SEU. A resident of NYC, you can find him camping, exploring, and telling everyone about what birds he saw at his local birdfeeder.

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