Sea Snake Animal Facts | Hydrophiinae

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The sea snake is incredibly venomous, even more than a cobra!

There are over 60 species of sea snakes that belong to the same family as cobras, Elapidae. They are highly venomous and are divided into two groups.

Firstly, the true sea snakes belong to the Hydrophiinae subfamily. In addition, they are related to Australian terrestrial elapids. The second group is sea kraits, belonging to the subfamily Laticaudinae and closely related to Asian cobras.

Sea snakes are venomous, and their toxins are very potent; however, if they do bite humans, fatalities are rare due to the small output of venom because their fangs are so short.

There are 55 species of true sea snakes that typically measure between 3.2 to 5 feet in length, but there are individuals that can grow up to 8 feet.

To adapt to their surroundings, sea snakes have a flat body with a short tail resembling an oar. In addition, they have valvular nostrils are perched on top of their snouts and they have lungs that stretch through the entire length of their bodies.

Sea Snake Amazing Facts

Where to Find Sea Snakes                            

Sea snakes are found in coastal areas in the Western Pacific and Indian oceans and span from the eastern regions of Africa to the Gulf of Panama. However, some species live in the open ocean on the western coasts of the Americas, like the yellow-bellied sea snake.

But their preferred habitat is shallow water, not deeper than 100 feet (but they can go down to 300 feet) because they need to hunt on the sea bed among coral reefs. In addition, certain species prefer hunting on soft bottoms consisting of mud, and others prefer hard bottoms, like corals.

Some countries where you can find sea snakes include:

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Types of Elapids

The family Elapidae or Elapids are venomous snakes with permanently erect fangs, that include the sea snake. Most of the species in this family will react to a threat by rearing upwards and spreading their neck-flap. They prefer warmer temperatures and occur in tropical and subtropical regions worldwide. Elapids vary in size and are generally neurotoxic. There are around 360 species in this family and over 170 subspecies, which include:


Cobras come in all sizes and colors; some are yellow, black, red, banded, or mottled. They are generally large snakes, with many measuring more than 6 feet. The biggest true cobra is called the forest cobra and grows 10 feet long. In addition, the Ashe’s spitting cobra is the largest spitting cobra, measuring 9 feet long.

On the other hand, the smallest species is the Mozambique spitting cobra that reaches 4 feet long when fully grown.

Lastly, the King cobra lives up to its name and is the longest of all venomous snakes measuring a whopping 18 feet long!


Mambas occur in the rocky hills and savannas of eastern and southern Africa. They hold the title of Africa’s longest venomous snake, which reaches 14 feet when fully grown. In addition, they are super fast and can travel 12.5 miles per hour.

Tiger Snake

Tiger snakes derived their name because they have stripes resembling a tiger, but not all have a striped pattern.

Being bitten by a tiger snake is very dangerous because they are one of the most venomous snakes on the planet, and its fangs measure between 0.14 to 0.20 inches.

They are great swimmers and glide through the water with ease. When threatened, the tiger snake will stand at attention and flatten their heads, similar to a cobra.

Sea Snake Scientific Name

The Sea snakes’ scientific name is Hydrophiinae, and they belong to the family Elapidae. In addition, sea snakes fall under the class Reptilia. Most sea snakes fall into this category, but they are not the only ones. It also includes many species of venomous snakes like:

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Sea Snake Population and Conservation Status

Because there are so many species of sea snake, it’s hard to estimate their population size and conservation status under one umbrella. However, there are several species of sea snake on IUCN’s Redlist listed as Endangered.

For example, the Dusky sea snake shows up as Endangered, while the Crocker’s sea snake is listed as Vulnerable. Sadly, two species are listed as Critically Endangered: the Short-nosed and Leaf-scaled sea snake.

How to Identify Sea Snakes: Appearance and Description

Sea snakes come in various sizes and colors. However, most of them measure between 4 to 5 feet long and usually have distinct ring patterns.

Similar to most snakes, they are long and slender, but their tails are unique because they are flat, and the tip of the tail resembles a paddle, which helps with swimming.

Laticauda laticaudata Blue Banded Sea Snake
Sea snakes come in various colors and they usually have distinct ring patterns, like this blue-banded sea krait.

©Bramadi Arya / CC BY-SA 4.0 – License

Sea Snake Reproduction and Lifespan

Sea snakes are typically ovoviviparous, except for a single genus, the Sea Krait, which is oviparous, and includes 5 species that lay their eggs on land. Ovoviviparous is when the eggs are kept in the uterus until they hatch.

The females give birth to live young, who are generally quite large (sometimes half the length of the mother). Generally speaking, sea snakes can live for about ten years.

Sea Snake Venom: How Dangerous are They?

The sea snake is incredibly venomous, even more than a cobra! Their venom is a deadly combination of myotoxins and neurotoxins. Luckily, there haven’t been many recorded sea snake bites, and those that did get bitten all lived. Sea snakes rarely deliver venom when attacking due to their small fangs.

Sometimes the bite is painless, and no symptoms occur. However, a few small teeth can remain behind in the wound.

But, when symptoms appear, it takes anywhere from 30 minutes to several hours. They can include:

  • Thirst
  • Headaches
  • Vomiting
  • Stiffness
  • Sweating
  • Muscle pain
  • Swollen tongue
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Eventually, muscle degradation and paralysis kick in, and it can be fatal if the poison starts to affect the muscles involved in swallowing and respiration. Unfortunately, antivenom is almost impossible to find because sea snake bites are few and far between.

Sea Snake Behavior and Humans

Sea snakes are very timid creatures and would rather retreat in the face of danger. They are completely opposite from the cobra’s aggressive nature, even though they belong to the same family.

Humans eat sea snakes, and they are often exploited for their meat, organs, and skin. Unfortunately, CITES has yet to protect the sea snake even though they are often taken in great numbers.

The Philippines was one of the biggest culprits because the sea snake’s meat has been used commercially since 1934. Eventually, it was necessary to implement local protection to avoid over exploitation.

Other countries to exploit sea snakes are:

Australia has since implemented special licenses to fish for sea snakes; however, there are many areas where they occur that are not controlled by governments and can not be monitored around the clock.

But their biggest threat is climate change, low reproduction rates, and bycatch, and these factors are killing their population numbers.

They have many predators and always need to be on the lookout, both from above and below. These predators include:

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Sea snakes can swim 2 – 2.5 mph.

The sea snake is incredibly venomous, even more than a cobra! Their venom is a deadly combination of myotoxins and neurotoxins.

Sea snakes usually prey on fish, eels, and fish eggs.

Sea snakes come in various sizes and colors. However, most of them measure between 4 to 5 feet long and usually have distinct ring patterns.

Yes, however, sea snakes rarely deliver venom when attacking due to their small fangs.