Olive-Headed Sea Snake: Diet, Habitat and Facts

The bigger sea snake (Hydrophis Major), commonly referred to as the olive-headed sea snake, is a venomous species of sea snake in the Elapidae family. It is known for its strong bite and huge, club-like tail, which are elongated and dagger-like.

Olive-headed Sea snakes have a head that is very prominent due to its color. These snakes get their name from the shape of their body. Their bodies are heavily serrated with a pattern of darker, brighter, olive-green, and grayish-brown bands.

Are you looking for solutions to rid your family of snake bites? Or do you have the curiosity to indulge in the facts related to this greater sea snake? You can read the details regarding this venomous snake here. We hope that you like it and come back to discuss more interesting facts about this deadly sea snake.

Facts and Features of Olive-Headed Sea Snake

Conservation status: Least Concern (IUCN 3.1)

Kingdom: Animalia

Phylum: Chordata

Class: Reptilia

Order: Squamata

Suborder: Serpentes

Family: Elapidae

Genus: Hydrophis

Species: H. Major

Binomial name: Hydrophis major (Shaw, 1802)


  • Hydrus major Shaw, 1802
  • Disteira doliata Lacépède, 1804
  • Disteira major – Boulenger, 1896
  • Disteira major – Cogger, 1983
  • Hydrophis major – Rasmussen, 1997

Length: 6.5 feet (2 m)

Weight: 3.3 kg (6.6 lbs)

Age: 15 years or longer (approximately 20 years)

Discussion About the Habits and Lifestyle of Olive-Headed Sea Snake

Based on evidence and studies of these sea snake species, let’s get some knowledge about this sea snake:

● Classification

The classification of this sea snake indicates its distinguishing characteristics. Hydrophis (from the Greek word for water) refers to its amphibious habits and aquatic habitat, whereas the Major means big in Greek.

This snake has a head that is very prominent because of the ruffled surface of its skin. It belongs to the Reptilia class in the Squamata order. Its family is Elapidae. The Elapidae is a family that includes the king cobra, the rattlesnake, the sea snakes, and Russell’s viper.

● Appearance

A distinguishing feature of the Olive-Headed Sea Snake is a section of skin that covers its head (the rostral part) and some of the upper portion of its body. Adults can grow up to 105 cm (3 ft 5+3/8 in) in length, with a tail that is 12 cm (4+3/4 in) long. What’s more? It has the following physical characteristics:

  • Yellowish or pale brownish dorsally, with darker brown or blackish crossbars.
  • Crossbars may be all the same width, or they may be alternately broad and narrow.
  • White ventrally, with or without small dark brown spots.
  • Dorsal scales imbricate (overlapping), strongly keeled on the neck, weakly keeled on the body; arranged in 31–36 rows around the neck, in 36 to 41 rows at midbody.
  • Ventrals 200–236.
  • Head moderate.
  • Body stout.
  • Rostral is as broad as deep.
  • Nasals are shorter than the frontal and more than twice as long as the suture between the prefrontals.
  • Frontal longer than broad, as long as its distance from the end of the snout.
  • One preocular and two postoculars.
  • Two superposed anterior temporals.
  • Seven or eight upper labials, third and fourth entering the eye.
  • Only one pair of small chin shields.
  • Ventrals are distinguishable but very small, either smooth or bicarinate.

These specifications of the creature make it a magnificent and rare sea snake.

● Diet

Olive-headed Sea snakes eat small to medium-sized fishes. They also eat benthic invertebrates like prawns and crabs. They hunt their prey at night and prefer to rest, digest, breathe, and be intimate during daytime.

● Geographic range

The olive-headed sea snake is found in Southeast Asian waters and has been spotted on certain islands off the coast of Japan. The most frequently observed species of olive-headed sea snake is the familiar species, Hydrophis atrox, which is found throughout the Indo-Pacific region.

Wikipedia organization has given the following locations:

“It can be found in the waters (marine, brackish, and fresh waters) around southern New Guinea, New Caledonia, and Australia in the eastern Indian and western central Pacific Oceans (New South Wales, Northern Territory, Queensland, and Western Australia).” (Source)

● Habitats of olive-headed sea snake

Though less conspicuous than the banded sea snake, the olive-headed sea snake is easy to find in the wild. It lives in coral reef areas and is also found in shallow waters.

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These sea snakes mainly lie on the sea floor, where they are more likely to escape from predation. They are nocturnal and need to rest during the day because of their amphibious lifestyle.

Olive-headed Sea snakes prefer to hide in rocky areas and on the corals. They can sometimes be found near sponges, driftwood, mud, and sand. They like to rest near rock walls and steep ledges.

● Olive-Headed Sea Snake and Humans

Olive-headed Sea snakes are highly venomous but rarely bite humans. But there are few reports of snake bites around the world.

All these cases turned out to be misidentifications, as the snakes had other identifying characteristics, such as elongated bodies and ridges on the back of the head.

● Reproduction

Like the majority of sea snakes, the olive-headed sea snake gives birth to viviparous young. Although only one is utilized during mating, male sea snakes have two hemipenes, each of which is an independent, self-contained penis.

Sea snakes must surface for air for mating, which lasts for extended periods of time. The male is pulled behind the female by the hemipenis as she swims to the surface while the female controls her respiration. Males can’t stop engaging in mating till it’s over.

Female Olive-headed Sea snakes typically have 6–12 young in each litter. The snout-vent lengths of males and females at sexual maturity are 84 cm and 71 cm, respectively. A total of 45 reproducing females (mean s.e. = 4.9 0.3) had broods of up to ten young.

At birth, the mean snout-vent measured 42.7 cm (s.e. = 0.9 cm). Gestation in northern Australian waters was predicted to last six to seven months, with delivery taking place in September. Females seemed to procreate annually. (Source)

● Population and Conservation Status

Its Conservation Status is the Least Concern according to the IUCN Red List criteria. This shows it is not endangered species of sea snake. (Source)

The olive-headed sea snake is regarded as a notable representative of Queensland’s subtropical sea snake biodiversity. Each year from August to January, it becomes rather prevalent in the waters between Bundaberg and Fraser Island. (Source)

Is The Olive-Headed Sea Snake Venomous? Lets’ Discuss It in Detail

Yes, the olive-headed sea snake is a highly venomous sea snake. It does not bite until provoked or feels unsafe. But what to do if it bites a human? We will discuss it in detail below.

Though this snake is very large and venomous, it is not considered to be the most dangerous sea snake. Its mediocre potency and its low toxicity to fish, invertebrates, and shellfish have been well documented.

Its bite can cause serious symptoms such as swelling, numbness, and severe muscle spasms, and if not treated promptly, can lead to death. It also causes nerve damage and muscle paralysis. Olive-headed Sea snake bites often do not cause symptoms until hours after the venom has entered the body.

How Venomous Is the Olive-Headed Sea Snake? Let Know the True Facts

It is not known exactly how common this snake is, but due to its dangers, as well as a venomous snake that scientists have named the same species, the olive-headed sea snake, their occurrence is unlikely to be rare.

The olive-headed sea snake is described as a potentially dangerous and fatal snake species due to its venom.

When it comes to their venom, though, the greatest snake does not come from a place of terror. Scientists say the Olive-Headed Sea Snake only injects venom when defending itself, making its venom pretty harmless in the meantime. However, some researchers have found it a non-gentle and aggressive sea snake.

The olive-headed sea snake’s venom contains enzymes and other anesthetic components that make the death of the body soften and dissolve, while the action of the venom pumps blood out. So, it’s good to keep yourself safe from these venomous snakes.

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Why the Olive-Headed Sea Snake Bite?

Possible causes include someone who has touched or come into contact with a dead olive-headed sea snake or a person who came into contact with its saliva. The venom from the olive-headed sea snake’s fangs and the tail is too powerful for most people to have a serious reaction.

When a person comes into contact with venom, it’s typically harmful to the life of that person. However, it may be that one of the individuals that have been bitten has a different response than the others. They might have a rapid onset of intense pain. Some individuals might have reacted by not feeling themselves for an hour or two.

5 Major causes of Hydrophis Major bite:

Here are a few other causes of Hydrophis Major bite:

  • An uncovered body while diving in the sea is a possibility.
  • The person might have touched it with a fin.
  • Being splashed while in the sea.
  • It may also be relaxing. The snake’s feeding patterns may cause them to become agitated.
  • If the victim is sucked into the iris of the eyes, a dead olive-headed sea snake will then sting him or her and inject the venom. It’s just possible that it might happen.

The exact cause of their venomous nature is still unknown, though it has been hypothesized that the predators of their prey can use its toxins in their attack against their prey.

The hydrophis major is also thought to be a direct competitor to other sea snakes for the same food source. This could play a role in the biology of their venoms.

What Are the Symptoms of An Olive-Headed Sea Snake Bite?

The symptoms of the olive-headed sea snake’s bite will depend on the exposure. Each individual reaction is different and is linked to the amount of venom injected, where it was injected from, and how quickly it was injected.

Once bitten, someone will experience signs and symptoms immediately. If not, expect to start noticing these symptoms a few hours after being bitten. The symptoms of the olive-headed sea snake’s bite include:

  • Acute inflammation of the gums, lips, tongue, and mouth, with shortness of breath
  • Anxiety, restlessness, restless drooling, panic, fatigue, and sweating
  • Numbness or tingling of the hands and feet
  • Nausea, vomiting, diarrhea
  • A rapid heart rate
  • Reduced blood pressure
  • Paralysis
  • Severe agitation
  • Dizziness
  • Headache
  • Jaundice
  • Muscle tremors, involuntary movements

The most concerning complications of this snake’s venom are:

  • Spinal cord paralysis
  • Blindness, loss of vision, and in some cases, mental retardation
  • Seizures and a drop in blood pressure
  • Severe envenomation can result in both short- and long-term damage to the kidneys, heart, blood vessels, and nerves.
  • Severe or persistent low blood pressure can result in uncontrolled or uncontrolled bleeding.
  • Stroke
  • A very rare form of meningitis
  • Severe swelling of the brain or brain herniation
  • Stupor, coma, and eventual death

A person may not experience all these symptoms at once. Each bite reaction is different. The symptoms of the bite will lessen gradually with time if the victim is treated well.

Seek medical attention for the symptoms of an olive-headed sea snake bite immediately. The symptoms can be reduced or even eliminated, however, if treated immediately.

Is There Any Antivenom for The Treatment of Olive-Headed Sea Snake Bite?

Yes, an antivenin polyvalent sea snake is now available for the treatment of the bite of this snake. However, concern the toxicologist so that he/she can find that this may or may not be effective against the snake’s venom.

Due to the extremely high toxicity of the venom of this species, it is crucial that first aid is administered right away (constrictive bandage, etc.) and that the patient is taken as quickly as possible to the hospital.

These venomous snakes do not always inject venom when biting; those bites are known as dry bites. The person may not have been envenomated even if there are no symptoms.

The mixture of proteins, enzymes, amino acids, peptide chains, lipids, and even some metals that make up snake venom is extremely complicated. The type of bite that injects venom into the body is one of the following:

  • Intramuscular injection
  • Intraperitoneal injection
  • Intravenous injection
  • Subcutaneous injection
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All these injections have different properties and benefits.

How To Avoid Olive-Headed Sea Snake Bite?

If you encounter a snake in your area, though, here are some tips for avoiding being bitten:

  • Take a photo of it. If you encounter an olive-headed sea snake, it is the best way to report the snake to scientists.
  • Wear long pants and shoes. If you’re wearing sandals, put them on, or even in the case of a casual encounter, simply remove them for a photo.
  • Try not to move around where the snake is, especially if you’re about to walk near it. This is because a frightened or alarmed snake may bite and try to defend itself.
  • If you’re bitten, do not panic and act immediately. This is because your health should let the poison be taken care of by the snake’s natural metabolism.
  • Take photos and records of the incident, but make sure to leave the snake alone. Do not attempt to kill it or remove its body.

Whether you are bitten by an olive-headed sea snake or not, this fact should be enough to change your perception of this snake and make you fear it a bit less.

Fascinating Facts About Olive-Headed Sea Snake

Here are some interesting things you should know about this remarkable sea snake:

  • The subfamily Hydrophiinae of snakes, which includes more than 50 species of “really aquatic” sea snakes, includes Hydrophis major. The Hydrophiinae are completely adapted to marine life and habitat, with little to no association with terrestrial life and little ability to move on land.
  • According to scholarly research, its venom is frequently, many times more potent than land snake venom.
  • Olive-headed Sea snakes are part of an island-dwelling family of venomous snakes and only share a commonality in their venoms.
  • The greatest sea snake belongs to one of the most efficient sea snakes all over the world.
  • Most of the time, the person bitten by the olive-headed sea snake will feel no pain.
  • These sea snakes are used in various dishes because they feed on fish, and they can sometimes be served in the form of fish soup in various countries.

These facts will change how you perceive this beautiful sea snake.

Frequently Asked Questions (FAQs)

1. Is olive-headed sea snake carnivorous?

Yes, olive-headed sea snakes are carnivorous. It is part of an aquatic reptile family and therefore, it preys on fish. It also eats mollusks, crustaceans, eels, and fish eggs. These snakes are active during the day and would be most active in wet areas.

2. Which sea snake is the most poisonous?

There are a lot of poisonous sea snakes, but it is said that Hydrophis duboisii is the most poisonous one. It’s also known as the Dubois Sea snake.

3. How big is the olive-headed sea snake?

The olive-headed sea snake is 6.5 feet long. It’s counted as one of the biggest sea snakes in the world. The whole body of this snake is as long as a 6 feet man.

4. What is the speed of an olive-headed sea snake?

The speed of an olive-headed sea snake is 1 m/s. It is known as one of the biggest and most efficient predators of small and medium-sized fishes, as hunting fast prey is an easy task for Hydrophis Major.

5. What are the predators of olive-headed sea snakes?

Sharks, predatory birds, and large fishes are the predators of olive-headed sea snakes. Coral reefs are their shelter from these enemies.

6. What are the other names of olive-headed sea snakes?

Disteira major snakes, coral reef snakes, and the greater sea snakes are one of the most common names of olive-headed sea snakes.


Olive-headed Sea snake bites are extremely dangerous. If you’ve ever been bitten, you know it is always better to be safe. Hope you find these facts interesting and informative. Make sure to spread the word about these venomous creatures!


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