Not all snakes live on land. Some spend their days swimming through the sea. The beaked sea snake is known for its particularly potent venom.
Beaked sea snakes get their name from their hook-shaped snout. They are found in coastal areas in Southeast Asia, including India and its coastal islands. Beaked sea snakes feed on many kinds of marine life, though their favorite food is the catfish. Female beaked sea snakes can give birth to over 30 baby snakes at once, though only a few will survive to adulthood. Beaked sea snakes have venomous fangs that have neurotoxins over 4 times as dangerous as that of the cobra.
Let’s learn about the main identifying traits of the beaked sea snake. Then we’ll explore where it lives, what it eats, and how it defends itself with its highly venomous bite.
What Is A Beaked Sea Snake?
Beaked sea snakes have the scientific name Enhydrina schistosa. They get their “beaked” name because of the appearance of their face. Their snout has a distinctive downward turn that looks a lot like the beak of a bird. The rest of their body is stout and vertically flattened, and their head is relatively small compared to other snakes.
These snakes are also nicknamed the “hook-nosed sea snake,” the “common sea snake,” and the “valakadyn sea snake.” They are active during both the daytime and the nighttime.
These venomous sea snakes are excellent swimmers who spend most of their time in the water. They have a flat, paddle-like tail which they use to propel themselves through the water. While they breathe air like other snakes, their nostrils are valved, which means that they can be closed when the snake is swimming underwater.
- Beaked Sea Snake Average Length: 4 feet
- Undersea Depth Range: 25 to 65 feet below the surface
- Maximum Diving Depth: Up to 330 feet below the surface
- Maximum Time Without Surfacing: 5 hours
- Fang Length: less than 4 millimeters
Where Do Beaked Sea Snakes Live?
Beaked sea snakes are most plentiful around the coast and coastal islands of India. While there are 22 species of sea snakes living in that region of the world, beaked sea snakes are by far the most common species represented. You will also find these snakes in the seas around a variety of other South and Southeast Asian countries.
Beaked sea snakes prefer to live in the muddy waters near mudbanks and coasts. You will also commonly find them in mangrove swamps, estuaries, and rivers which feed into these coasts. Sometimes they are sighted in harbors and shallow bays as well.
However, these snakes can swim into deeper water to find food if necessary, using their ability to dive up to 100 meters below the surface of the sea. They can hold their breath for up to five hours as well.
On rare occasions, these snakes are seen venturing onto land, usually near mangrove forests. However, the snake will quickly return to the water.
Mistaken for Australian Beaked Sea Snakes
For a long time, it was believed that the range of beaked sea snakes extended to include parts of Australia, such as Queensland and Northern Territory, and New Guinea.
DNA testing eventually proved that the snakes in Australia and New Guinea, despite having a similar appearance and behavior to the beaked sea snakes elsewhere in Asia, were not actually the same species as the Enhydrina schistosa beaked sea snake.
The Australian beaked sea snake is now referred to as Enhydrina zweifeli. Its nicknames include the Sepik beaked sea snake, since many examples of this species were studied near the mouth of the Sepik River in New Guinea. It is also called Zweifel’s beaked sea snake.
This natural phenomenon in which 2 separate species develop common traits is known as evolutionary convergence. These different snakes experience similar environmental conditions, and so they evolved in similar ways. Fortunately, while both snakes are potently venomous, the same antivenom works to combat either snake’s bite.
How To Identify Beaked Sea Snakes
Adult beaked sea snakes have dorsal scales which are a dull olive-green or green-grey color. Their belly scales are white. On all sides, these snakes have dark crossbands that are widest on their dorsal side, taper to points on the flanks, and fuse together towards the tail. An older adult beaked sea snake loses its dark crossbands and their color fades to a bluish-grey hue.
The color of these snakes may serve as a cue to other animals that the beaked sea snake is venomous. This serves as a defense mechanism to deter predators. A snake that has venom can fight back well, and it might not be good to eat anyway.
What Do Beaked Sea Snakes Eat?
Beaked sea snakes are carnivores. Their diet primarily consists of the kinds of animals they find around them in the water.
Beaked sea snakes can open their mouths wide enough to swallow a fish which is larger than twice the diameter of the snake’s neck. Beaked sea snakes commonly feed on the following:
- Fish, such as catfish, pufferfish, and eels
- Crustaceans and mollusks, including prawn, squid, and crab species,
- Eggs of various sea creatures, including fish
While other species of sea snakes are more generalist feeders, eating whatever comes their way, beaked sea snakes have a preference. Catfish are by far their favorite food. These snakes are usually found caught up in fishing nets full of catfish.
There is an apparent correlation between the size of the beaked sea snake’s snout vent and the size of the prey it eats. Snakes with a larger snout vent will usually eat larger prey, and snakes with a smaller snout vent will usually eat smaller prey. However, beaked sea snakes of all sizes can wrap their flexible jaws around food of nearly all sizes.
How Do Beaked Sea Snakes Hunt?
These sea snakes do not depend much on their eyesight in the murky water. Instead, they use their senses of smell and touch to find their prey. Because they are not using their vision alone to hunt, the snakes are equally adept at hunting during the day and during the night. However, they are usually witnessed more actively feeding at night than during the day.
Like most snakes, beaked sea snakes use their forked tongue to smell. They catch olfactory particles in the air with their tongue and pass the particles along to the Jacobson’s organ in their mouth. This organ effectively combines the senses of smell and taste to give the snake a sense of which direction the prey they’ve smelt is in.
With fangs less than four millimeters long, beaked sea snakes might not seem all that intimidating. However, these snakes have a strong venom which they use to kill their prey. In addition to the venom, beaked sea snakes produce a powerful enzyme that begins to digest the prey from the moment the snake bites it.
Like most other sea snakes that hunt fish, the beaked sea snake will wait until its prey has slowed down and stopped struggling before it eats. It will turn the prey around and swallow it headfirst. Like all snakes, beaked sea snakes do not chew. Their flexible jaw allows them to swallow food which is much larger than the width of their body.
How Do Beaked Sea Snakes Digest Their Food?
After swallowing their prey, it takes time for a beaked sea snake to digest its food. In warm-blooded animals like humans, we are able to maintain our internal temperatures, so our stomachs are already at a good temperature for digestion. However, like all snakes, beaked sea snakes are cold-blooded animals. They depend on the temperature of the surrounding water or air to help them digest.
The ideal temperature for digestion for a beaked sea snake is 86 degrees Fahrenheit, or 30 degrees Celsius. The snake will enter a dormant state while it digests its food. The beaked sea snake’s digestive enzymes are able to absorb nearly all parts of the prey animal’s body, except for particularly hard parts such as bones or claws. These leftovers are then excreted as waste.
What Eats Beaked Sea Snakes?
Sea snakes are not aggressive creatures. They usually only attack to get food or in self-defense.
Not many animals seem to enjoy eating beaked sea snakes, taking their color as a cue for their venomous bite. Inshore predators commonly eat these snakes, such as some large species of fish and estuarine crocodiles.
In the seas, barnacles and algae tend to grow on species of beaked sea snake. These organisms do not have any overt negative effect on the snake. However, they can limit the snake’s ability to move if they build up so much that they weigh down the snake. At this point, the beaked sea snake will shed its skin for a new one without any barnacles or algae on it.
The biggest threat to beaked sea snakes are not the predators who hunt and eat them, but human fishing boats. According to researchers at Pondicherry University in India, prawn trawling and boat seine nets are the top threats to beaked sea snake numbers. One or more snakes are often tangled up in these nets at a time, often leading to the snakes dying and potentially biting the fishermen as the snake attempts to escape.
How Do Beaked Sea Snakes Move?
Beaked sea snakes do not have the expanded scales on their belly which land snakes use to move around on the ground. They don’t need those scales to swim. Beaked sea snakes have a flattened tail which works a bit like a paddle, helping to propel themselves through the water.
Beaked sea snakes move in a serpentine motion. The snake contracts its body, pushing against the water around it and propelling itself forward.
The lungs of these sea snakes are stretched out inside the body, which allows the beaked sea snake to retain more oxygen for longer periods of time. They also have the ability to perform cutaneous respiration.
Cutaneous respiration allows the snake to diffuse oxygen out of the water around them, through their skin, much like a fish. They are also able to release carbon dioxide out through their skin. However, this is not enough oxygen for the snake to survive on, and it will return to the surface after a maximum of five hours underwater.
Are Beaked Sea Snakes Venomous?
Their venom is over 4 times as powerful as a cobra’s venom. This venom allows the snake to more effectively hunt and digest its prey, and also serves as its primary defense mechanism.
There is a common belief that because sea snakes have short fangs, they are not very good at biting. However, while their fangs are short, they are more than capable of penetrating human skin. The snake can also open its mouth wide enough to bite the width of the average table top. This is more than enough width to get around a human hand or foot.
Not every beaked sea snake bite results in envenomation. The snake can control whether it injects any venom, and also how much venom it injects. As a result, only some beaked sea snake bites are even fatal to a human. Less venom is required to take down the snake’s prey, and it knows how to pace itself and be versatile to confront different threats. Only 1.5 milligrams of beaked sea snake venom is necessary to kill a human.
Beaked sea snakes do not go out of their way to attack humans. However, if they feel cornered, they will strike out. The most common situation in which humans are bitten by sea snakes is on trawling ships. The snakes are sometimes accidentally hauled into the ship along with a big net full of fish. At that point, the fishermen’s best bet is to grab the snake by the tail and throw it overboard again.
What Kind Of Venom Do Beaked Sea Snakes Have?
According to the University of Malaya, short and long neurotoxins are the major lethal components of the beaked sea snake’s venom.
A neurotoxin is a kind of venom that attacks the victim’s nervous system. This means that when a beaked sea snake bites a fish, the fish quickly loses its capability for neurons to interact with each other. This causes paralysis, not only keeping the fish from swimming away but also causing it to lose its ability to breathe.
Beaked sea snakes have one of the most deadly venoms of all known snakes. According to the Central Marine Fisheries Research Institute, beaked sea snakes are responsible for ninety percent of fishermen deaths from sea snake bites around the world.
Researchers at East Carolina University add to this that significant envenomation only occurs in 20% of beaked sea snake bites. Nevertheless, all sea snake bites should be treated promptly.
If you were bitten by a beaked sea snake, you would not feel any intense pain in the area of the bite itself. Symptoms from the venom set in around thirty minutes after the bite takes place.
- Venom Symptoms: Stiffness, muscle aches, jaw spasms, moderate to severe pain in the bitten limb, blurred vision, drowsiness, respiratory paralysis, darkened urine, acute renal failure, irregular heartbeat, damage to kidneys
- What To Do If Bitten: immobilize the victim, compress the envenomed area, transport the victim to a medical facility
- What Will Doctors Do: artificial ventilation, crystalloid hydration, apply beaked sea snake antivenom
Fortunately for humans, beaked sea snake venom also provides its own cure. Venom can be extracted from the beaked sea snake in order to create an antivenom to cure it. This process is known as “milking.” A beaked sea snake must be milked several times in order to generate enough venom to create a usable amount of this cure.
The venom is then injected into another animal, such as a horse or a sheep. The plasma of the injected animal is then extracted and used to create antivenom. With the right antivenom, even a deadly bite can be cured.
Are Beaked Sea Snakes Social Animals?
Beaked sea snakes are generally solitary animals. They do not have any significant long-term relationships with other snakes, either from the same or different species.
While they do not seem to go out of their way to attack or eat other snakes, they also do not make any effort to socialize. However, beaked sea snakes will come together for reproductive purposes during the mating season.
How Do Beaked Sea Snakes Reproduce?
Beaked sea snakes are dioecious. This means that like most snakes, they have distinct male and female individuals. During mating season, these snakes come together to breed. Spikes or grooves on the male snake’s genitals will help it hold on to the female snake’s cloaca.
According to Copeia, male and female beaked sea snakes have synchronized reproductive cycles. They mate once per year. These snakes are viviparous, giving birth to relatively large, live young.
Researchers at the Central Institute of Fisheries Technology in Cochin report that beaked sea snakes give birth to up to 30 baby snakes every time they breed. However, there is a very high death rate for young sea snakes, and only a small proportion of these hatchlings survive to adulthood.
- Mating Season: September to October
- Gestation Period: November to February or March
- Growth Rate During First Year of Life: 0.12 centimeters per day
- Maturity Age: 18 months
- Female Age at First Clutch: 24 months
- Average Weight At Birth: 0.4 ounces.
- Clutch Size: 30 hatchlings or more, with an average of 18 babies; clutch size increases proportionally to the size of the female snake
- Hatchling Survival Rate: 10-20% of hatchlings survive the first year of life; 6% of females survive to reproduce
- Maximum Age in the Wild: Around 4-5 years
Beaked Sea Snake Fun Facts
Beaked sea snakes have glands that allow them to eliminate excess salt, if they absorb too much.
In many Asian countries, the beaked sea snake is considered a delicacy. These snakes are sometimes hunted for their meat or skins. Most beaked sea snake death at the hands of humans, however, is accidental.
Male beaked sea snakes have two penises, referred to as hemipenes. Only one of these organs is actually used for reproduction.
All sea snakes in India, including the beaked sea snakes, are protected under the India Wildlife Protection Act of 1972.