Sea snakes

Sea snake, Whitsundays

Approximately 15 species of sea snakes can be found on the Great Barrier Reef. While all produce lethal venom – used to paralyse their prey of fish, prawns, and molluscs – it’s rare they’ll use it on creatures they don’t perceive as food, such as a diver or snorkeller, that are far too large to eat.

Most bites to humans are a result of feeling threatened, so obviously handling or touching these creatures is not advised. Below are commonly asked questions about sea snakes.

What’s the difference between a sea snake and a land-dwelling snake?

The most obvious difference is that a sea snake has a paddle-shaped tail, which plays a vital role in propelling itself through the water. Another interesting difference is that sea snakes give birth to live young.   

Do all sea snakes bite?

While all Australian sea snakes are venomous they are reluctant to bite and are not known to be aggressive, however, this can differ from species to species. While there is the common train of thought that sea snakes don’t bite as their jaws are too small, the fact is they can open their jaws wide enough to swallow prey and are said to be able to bite a man’s thigh. But it is rare for this to happen – as they’d rather preserve their venom for something they can tuck into.

Are they easily agitated?

No, they are generally docile and aren’t looking for a fight. Most land-dwelling snakes would rather slither away – same goes to their sea-based relatives. 

Where are they found and when?

Sea snakes can dive to depths of 100 metres. With their enormous lungs, they can stay submerged for two hours, or even more, but will surface for air when needed. They are active both day and night and can even be found basking in the sunlight at the surface of the ocean, both in the morning and late afternoon.

What should I do if I see one?

As with any wild animal that could pose a danger, they are best left alone. While sea snakes generally won’t bite unless threatened, they should still be respected.

Is the venom lethal to humans?

Yes, the venom can be lethal to humans but there have been no reported deaths from sea snakes.

Is it true the yellow-bellied sea snake is one of Australia’s most dangerous snakes?

The yellow-bellied sea snake is a true sea snake, spending its entire life in ocean waters throughout the tropical Indo-Pacific. A bite from this fella will yield a small yet powerful amount of venom that will attack nerve and muscle tissue. Fortunately, no known fatalities have been recorded in Australia, which is probably because this snake is rarely encountered by people.

Another one to watch out for is the beaked sea snake. A bite can result in paralysis and even death. There is, thankfully, an antivenom available.  

What are the symptoms of a bite?

A bite may show up as a small pinprick or you could see up to 20 fang marks. Pain may not be felt initially, but if venom has been injected then some not-so-pleasant symptoms will occur within three hours. These include:

  • muscle pain,
  • paralysis of the legs,
  • joint aches,
  • blurry vision,
  • difficulty swallowing or speaking,
  • droopy eyelids,
  • and vomiting.

How should you treat a sea snake bite?

Because it’s hard to predict how much venom has been injected, any bite should be considered life-threatening.

  • Call for emergency medical services immediately by dialling 000.
  • There is no benefit to sucking out the venom, instead try to keep the victim calm, still, and warm.
  • Use the pressure immobilisation technique, wrapping a bandage around the limb, starting at the fingers or toes end and working your way towards the body. The fingers and toes should still be pink; you don’t want to cut off circulation. Every 10 minutes the bandage should be removed for 90 seconds and reapplied. Repeat for the first 4 – 6 hours but hopefully, professional medical attention would have been received within this time.
  • An anti-venom will be given if your medical professional thinks it’s necessary.

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