Hydrophis – Amazing Facts About This Snake Genus

The genus “Hydrophis” belongs to the subfamily Hydrophiinae of the family Elapidae. This genus of snake belongs to one of the venomous sea snakes. Waters in Indo-Australian and Southeast Asian regions are typically home to species in the genus Hydrophis. Approximately 36 species are recognized as valid at this time.

This genus of snakes has been very well studied and has served to provide some fascinating information about this dangerous species. In addition, they are quite important as the venom in these snakes has proven beneficial for certain medical conditions.

Do you want to know about the stunning nature of Hydrophis? Or do you want to know more about them? Read on. We have some amazing facts about this deadly genus of the snake. You will be surprised to know about these facts.

Facts and Features of Hydrophis Genus

Kingdom: Animalia

Phylum: Chordata

Class: Reptilia

Order: Squamata

Suborder: Serpentes

Family: Elapidae

Subfamily: Hydrophiinae

Genus: Hydrophis

(Latreille In Sonnini & Latreille, 1801)

Type species: Hydrophis platurus Linnaeus, 1766

Species: 35

Synonyms: Disteira Lacépède, 1804

Length: more than 1100 mm

Weight: 90 – 240 grams

Age limit: 15 to 20 years

Discussion About the Habits And Lifestyle Of Hydrophis

The snakes from the genus of Hydrophis are beautiful sea creatures. Even the internal anatomy of these sea snakes is quite interesting, and they will encourage you to learn more about them.


Many species lie under the hydrophis genus, but more than 36 are recognized. These are some of the most common species of Hydrophis found in the Indian and Pacific oceans. The different and most common species of hydrophis sea snakes, with their locations and local names, are listed below:

SpeciesCommon namesGeographic locations
Hydrophis Annandalebighead sea snake, Annandale’s sea snakeIndian Ocean
Hydrophis anomalousanomalous sea snakeSouth Chinese Sea, Indian Ocean
Hydrophis atricepsblack-headed sea snakeSouth East Asia, the Indo-Malaysian region, and northern Australia are all examples of this. Southern Papua New Guinea
Hydrophis belcheriBelcher’s sea snakeQueensland and New Territories, Australia
Hydrophis bituberculatusBrooke’s sea snakeSouth East Asia, the Indian Ocean,
Hydrophis curtusShaw’s sea snake, short sea snake, Hardwicke’s sea snake, spine-bellied sea snakePersian Gulf, Indian Ocean, South China Sea
Hydrophis cyanocinctusannulated sea snake, blue-banded sea snakeIndian Ocean and Western Pacific Ocean
Hydrophis czeblukovifine-spined sea snakeIndo-Australian and South East Asian waters
Hydrophis fasciatusstriped sea snakeIndian Ocean, Western Pacific Oceans
Hydrophis gracilisHydrological Major in Western Australia and the Southern Pacific OceanHydrological Major in Western Australia and the Southern Pacific Ocean
Hydrophis Majorgreater sea snake, olive-headed sea snakeIndo-Australian and South East Asian waters
Hydrophis nigrocinctusblack-banded sea snakeJapan, Sri Lanka, the Philippines, the Pacific Islands, New Guinea
Hydrophis Platurusyellow-bellied sea snakeIndian and Pacific Oceans, Japan, Australia, New Zealand, Pacific Islands
Hydrophis schistosebeaked sea snakeIndian Ocean and Persian Gulf to the Pacific Ocean
Hydrophis PeroniiPeron’s sea snakeGulf of Siam, Thailand, Vietnam, the South China Sea, the Philippines, Indonesia, the coast of Guangdong, and the strait of Taiwan


One of the most interesting facts about this genus is the shape and colour of their bellies. In addition, the snake’s head is the centre of attraction in this genus. A well-defined forehead characterizes it, and the face shape is also attractive and striking.

What’s more special about their appearances? The dorsal scales are paired, while the ventral scales are unbranched. These species of Hydrophis are characterized by long, slender bodies and deep, pointed heads with a mouth lined with keels. Their heads are quite similar to that of the reticulated sea snakes.

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Their integument makes them unique among other sea snake species. Hydrophis species also have scales resembling non-overlapping polygonal knobs with flat outer surfaces that are presumed to have filamentous sensillae.

Here are a few general and common characteristics of these specialized species:

  • The tail, trunk, neck, and head make up the body.
  • All sea snakes have tails resembling paddles, and many of them have their bodies compressed laterally to resemble eels.
  • The body is elongated, the lateral length is around 2 meters, and scales are all over it.
  • Dark olive green, yellow crossbars, and a pale region make up the overall colouring.
  • Large shields cover the head and are blurry. The nose, mouth, and eye are found in the head.
  • These species of sea snakes seem to be awake throughout the day and at night.
  • They have tiny, rounded eyes with rounded pupils in pairs.
  • The loreal shield is lacking, as are the ventral scales. Three and four supra-labials touch the eyes, with one pre-ocular, two post-oculars, and 7-8 supra-labials present.
  • They have 14–18 maxillary teeth.

Moreover, it is clear from the animal’s compressed and adapted tail for swimming and other characteristics, as mentioned above, that it is a hydrophis. Tail in oar-like.

Diet and Nutrition

The snakes have a very specific diet and are dependent on the location of where they are located or what is available as prey at that time. Mostly, they feed on eels, fish, eggs and crustaceans.

All these species are known to swallow the prey whole and to kill it before or after swallowing it. While eating, they may bite their prey, and sometimes, they actually spit the prey out. They also like to play tricks on the prey when they have swallowed it.

Some of the sea snakes do this by trying to make the sounds of a helicopter to attract their prey in the air. The prey of the Hydrophis species preys in a very friendly manner.

Geographic Range

Hydrophis genus sea snakes are found in Southeast Asian and Indo-Australian waters. According to facts and figures, India, the Bay of Bengal, the Malasiya Archipelago, and the Pacific coast from southern Mexico to northern South America are all home to the hydrophis or sea snake.

Hydrophis ornatus | Source: Wikipedia

These sea snake species are commonly found on muddy, sandy ocean floors. They love to hide in coral reefs to protect themselves and for hunting purposes. Certain species favour soft bottoms (mud or sand) when hunting their prey, while others prefer hard bottoms (corals). Hydrophis specializes in burrowing eels.

Habitats of Hydrophis

In winter, they seek cooler habitats and prefer to reside close to the water’s edge. During the summer, they move to open areas to avoid the sun’s heat.

If the temperature is very high in the summer, the snakes have to migrate up in the hills and lowlands to maintain their body temperature. In this way, these species of Hydrophis inhabit specific environments.

The hydrophis, or sea snakes, are extremely harmful to humans. They have neurotoxic venom. The poison paralyzes the muscles and devours the body cells. However, they seldom attack humans.

Their behavior towards humans is to stay away, scare, and away from humans. They don’t like to come to the surface because of this reason. To reduce the potential threat posed by these sea snakes to humans, a variety of measures should be taken to minimize their habitat.

Besides the trouble of avoiding poisonous or venomous sea snakes, what are the animals in general that could be causing you danger or injury? Of course, the same applies to sea snakes as well, but the most abundant ones include bull sharks, stingrays, cat sharks, tarpon, and pelicans.

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Special precautions

  • Clearances, such as in marine reserves, should be undertaken to prevent their habitats from being disturbed.
  • Many kinds of fishing should be avoided, especially with boats that resemble their habitat.
  • Mud-mining activities should be avoided, especially if the sea snakes are close to being trapped.
  • Most importantly, humans should be cautious while handling the snake species.

In light of the above, the control of the sea snake species has been listed as a great concern by many governments worldwide.


The life cycle of these snakes involves an egg incubation stage and a newborn snake stage. The species of Hydrophis hatchlings mature into adults. The adults are viviparous. An average of 2 to 9 young are born when sea snakes give birth in the ocean. However, this number can reach 34.

They are known to be viviparous because the females deliver live young. Some hydrophis sea snakes also carry their young on their chests, as it is the common practice of all snakes. These snakes are also known to be seasonal and specific in their life cycle.

What Are the Special Features Of Hydrophis?

With a mean retention of 5.1 g/cm of the skin surface, the deep crevices between the scales (the “hinge”) catch and wick water along the body surface, comparable to that previously found in the rough, spiny skin of marine hydrophis snakes.

When the dorsal body extends above water when floating on calm marine slicks where they forage, this characteristic may keep the skin moist. This is one of the special features of the Hydrophis genus of sea snakes.

This characteristic may be attributed to four factors:

  1. cutaneous gas exchange requires permeability.
  2. water efflux gradients are less steep in aquatic environments than in terrestrial ones.
  3. physical protection is not as important in aquatic environments as it is in terrestrial ones; and
  4. the frequency of ecdysis is higher, which is thought to be an anti-fouling mechanism.

These qualities differentiate hydrophis from other closely related snake genera. They play an important role in providing hydrophis snake species with an advantage over other snake species in their habitats, such as coral reefs.

Are The Hydrophis Genus Sea Snakes Venomous?

Yes, they are venomous. The extent of venom delivery, however, is highly variable. A venom gland has been described in many species of the genus. A young male hydrophis can be toxic, as well as a mature female.

In many cultures, there is little or no fear factor regarding snakes or snakes. Even so, it is reasonable for humans to be cautious about them because some species of Hydrophis venom are potent enough to cause human death and can be fatal.

For example, lethal doses of the snake’s venom are found to be lethal to humans when fully enveloped in human skin. There have also been reports of fatalities due to the effects of snake venom in certain medical conditions.

According to NCBI research, 50 % of bites are dry bites from sea snakes, and 50 % of the time, significant envenomation is given. The research stated that:

“Without proper treatment, morbidity and fatality rates are severe because of the high LD50 of sea snake venom. However, the prognosis is generally favorable if supportive therapy, such as mechanical ventilation when necessary due to respiratory compromise, and antivenin medication is started quickly.” (Source)

It is important to remember that hydrophis sea snakes may be dangerous to humans and should be avoided. However, snakes have their way of dealing with humans. They often swim away or slither off when approached, so humans must also not get too close to them in any way.

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How Venomous Are Snakes of The Hydrophis Genus Snakes?

Hydrophis genus sea snakes are extremely venomous. This fact is known all over the world. Although they don’t bite without any reason, it doesn’t mean they are harmless creatures. Their venom is a mixture of neurotoxins and myotoxins.

Hydrophis anomalous | Source: Wikipedia

It is a blend of neurotoxins, such as envenomation of the median nerve, thalamus, and dorsal nerves, with mycotoxins, such as calcium channel blockers, calcium channel blocker, potassium channel blockers, and neuromuscular blockers. A small quantity of venom is enough to kill an animal or a human. This is what they do with their prey.

Can A Hydrophis Sea Snake Bite?

Yes. Hydrophis sea snakes can bite if provoked or sometimes without any reason. The hydrophis genus is an unassuming snake and is very quiet. They are also considered gentle but can bite as they use their venom as a toxin in defense if they feel threatened. So, do not try to provoke these species; they can bite you and cause serious complications.

What Are the Symptoms of A Hydrophis Bite?

The wader or swimmer may not even notice the bite because it is typically painless. There may still be teeth and fangs in the wound. The involvement of nearby lymph nodes is uncommon, and there is little to no local swelling. The most common result of many species’ envenoming is generalized rhabdomyolysis.

Early symptoms include

  • Headache
  • A thick feeling on the tongue
  • Thirst
  • Sweating
  • Vomiting
  • Numbness of the affected limb
  • Bradycardia (slow heart rate)
  • Severe hypotension
  • Flaccid paralysis
  • Wandering pupil (iris will not close completely)
  • Hyperalgesia
  • Loss of control over voluntary movements
  • Pain
  • Tremors and convulsions

Between 30 and 210 minutes after the bite, there is a generalized onset of pain, stiffness, and tenderness of the muscles. Trismus is typical. The muscles hurt when they are passively stretched.

Later, like in other neurotoxic envenomings, ptosis is followed by gradual flaccid paralysis. Until the respiratory muscles are severely damaged to the point of respiratory failure, the patient is still awake.

Is There Any Treatment for The Bite Of Hydrophis?

To reduce the extent of venom toxicity, no operation can be performed on humans by medical personnel. Treatment starts with warming the affected limb and splinting the limb. Cardiac medications and blood-pressure-reducing medication should be administered to prevent the cause of hypotension.

Taking antivenin or providing mechanical ventilation and oxygen supply can be used in a case of severe envenomation. In addition, envenomation and passive ventilation, intravenous diuretics, and intravenous potassium channel blockers should be performed as soon as possible. 

Calcium channel blockers, calcium channel blockers, and vasodilators, including vasopressin, may be used to reduce cardiac arrhythmias, thereby preventing ventricular fibrillation. Cardiovascular and vascular medications may also be administered.

Patients are strongly recommended to remain in a hospital until completely recovered, as they will have to be monitored after discharge. Concerning the toxicologist, he/she must confirm the diagnosis and perform a detailed autopsy to identify the species of hydrophis snakes to establish the exact nature of the sting.

Fascinating Facts About Hydrophis

Here are some nice facts about hydrophis:

  • They are among the air-breathing vertebrates, along with whales, that are almost entirely aquatic.
  • Hydrophis can stay underwater for several hours, possibly up to eight or more.
  • Hydrophis species can be found in all the world’s tropical and subtropical seas.
  • Hydrophis is often misidentified as the coral snake or king cobra, but it’s a different genus of sea snakes.
  • Hydrophis is considered one of the world’s most poisonous snakes.
  • The venom is completely different from the rattlesnake’s venom, being more highly glycosylated.
  • Some individuals may have to take antivenom several months to months after the bite before their symptoms subside completely.


What is the habitat of hydrophis?

Hydrophis is aquatic and semi-aquatic. They are most common in tropical waters like the Bahamas and the Amazon. Their preferred habitat is in coral reefs, where they like to hang out.

Can Hydrophis venom be used as a medical antivenom?

Yes, some of the toxins can be used as antivenom. They do not show antivenom-specific antivenom reactions. But the antivenom sometimes works against other toxins in the same family.

What is the deadliest snake in the sea?

Dubois’s sea snake is the deadliest in the sea. Its mosquito-like bite can easily kill a human.

What is the role of snake antivenom?

It is only effective in local treatments for symptoms due to envenomation. It will be needed for those cases where systemic complications occur. For the rest, lifestyle adjustments can help minimize symptoms. It can prevent the occurrence of necrotic tissue so that complications can be avoided.


The hydrophis genus of sea snakes is interesting to study because their lifestyle is different, and they inhabit various environments. If you come across a Hydrophis snake, please make sure to notify the authorities and receive help. Only antivenom can prevent fatal hemorrhagic symptoms.

If a venomous snake bite you, you should immediately go to the hospital. The risk of any serious complications is minimal if the symptoms are treated. Hope you have fun reading.

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