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Symptoms and Signs of Sea Snake Bite

Doctor's Notes on Sea Snake Bite

Sea snakes are venomous animals found in tropical and warm waters of the Pacific and Indian Oceans. Sea snakes are usually not aggressive unless provoked or cornered. Bites often occur when fishermen are removing the snakes from fishing nets or if the snake is stepped on while wading in the water. Although they are highly venomous and their venom is very potent and toxic, only some bites result in significant symptoms or envenomation. The venom is injected by fangs but most sea snake species’ fangs are not long enough to penetrate through a wetsuit.

Initially, sea snake bites do not cause pain and there may only be a small pinprick where the bite occurred. There may be anywhere from 1 to 20 “fang” marks. When symptoms do occur they usually begin within 3 hours of the bite and may include muscle pain, inability to move the legs, joint aches, blurred vision, "thick tongue" with difficulty swallowing or speaking, excessive saliva production, vomiting, and droopy eye lids. If there are no symptoms within 8 hours of being bitten then venom injection is unlikely.

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Sea Snake Bite Symptoms

  • A bite from a sea snake does not cause pain initially.
  • The site of the bite may show only a small pin prick where the bite occurred without pain. Sea snakes bites could show anywhere from 1 to up to 20 "fang" marks.
  • The site of the bite rarely shows a reaction. The person who was bitten by the sea snake won't usually see redness, bruising, or other signs at the location of the bite, even if venom was injected.
  • Attempts should be made to capture or kill the snake for identification by an expert.

As sea snake venoms are neurotoxins, the typical symptoms of sea snake bites begin within three hours and include:

  • Painful muscles
  • Paralysis (inability to move) legs
  • Joint aches (arthralgias)
  • Blurry vision
  • "Thick tongue" with difficulty swallowing or speaking
  • Excessive saliva production
  • Vomiting
  • Droopy eye lids (ptosis)

If no symptoms develop within eight hours then venom injection is very unlikely.

Snakebites Types, Treatment, and Prevention Slideshow

Snakebites Types, Treatment, and Prevention Slideshow

For thousands of years, snakes have been associated with evil. They slither, hiss, and stare with unblinking eyes. One even deceived Adam and Eve in the Garden of Eden. So, it’s no wonder many people have a fear of snakes, which is called herpetophobia.

But are your snake fears justified? Every year in the United States, venomous snakes bite about 8,000 people. This is more common between April and October when more people are outside and active. But out of all those snakebites, 30 years of data show that no more than 12 people have died from snakebites in any single year.

While deaths from snakebite are extremely rare, snakebites do happen, and every one of them should be considered a potentially life-threatening emergency. In this slideshow, discover what snakes to watch out for, what you can do to prevent snakebites, why snake venom works the way it does, and what to do if you are bitten.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.