With 375 different species of venomous snake in the world, the battle for the title of the most venomous is almost as fierce as the snakes themselves.
We may fear the great anaconda and the notorious black mamba, but when it comes to sea snakes, many of us live in ignorant bliss, never even considering their deadly potential.
How deadly is the Belcher’s sea snake, or hydrophis belcheri, and is it the most dangerous in the world? Given that a single bite can kill you in just over 30 minutes, it’s certainly not worth trifling with, which is why knowing exactly what it looks like and where you’re likely to find it is crucial for your survival.
Contents
How to Spot a Belcher’s Sea Snake
Identifying a Belcher’s sea snake isn’t as easy as you might expect, partly due to the inaccurate descriptions and false identifications contained in many online resources. First categorized by British botanist John Edward Gray in 1849, the Belcher’s sea snake is also known as the faint-banded sea snake which gives us our first clue about their appearance.
Like most sea snakes, the Belcher’s body is banded with dark green stripes that appear black in most images. The rest of its body is of an uninspiring yellowish hue which often leads to it being confused with the yellow-lipped sea krait.
However, while the Belcher’s belongs to the subfamily of sea snakes known as “true” sea snakes or Hydrophiinae, its doppelganger is a member of the Laticaudinae family, otherwise known as “false” sea snakes or kraits.
This distinction is most easily discerned in the different tail shapes, although if you have an underwater DNA testing kit to hand, that will work too!
True sea snakes, like the Belcher’s, have a flat flipper-like tail which they use to propel themselves through the water at speeds of up to 12 mph.
The krait, on the other hand, has a flatter tail and more cylindrical body which enables it to crawl on land as well as swim through water.
A further distinction, should you be brave or stupid enough to take a closer look, is that the krait’s nostrils are situated on either side of its snout whereas the Belcher’s sea snakes are located on the top of its snout and are valvular, meaning they can be closed when underwater.
Belcher’s sea snakes may be dangerous but they’re not particularly large, with adults usually measuring between 50cm to a meter in length.
A slim snake with a small head, the Belcher’s sea snake has such a small mouth, the only really vulnerable places on a human body are the ears and the tips of the fingers.
Like most true sea snakes, the Belcher’s has small scales on its body, with its ventral scales, which run along the underside of the body, being much the same size as its dorsal scales.
Kraits are again different in this respect, having enlarged ventral scales similar to a terrestrial snake’s, that enhance its terrestrial movement.
As Belcher’s sea snake is almost entirely water-dependent, it has had no evolutionary desire to adopt this design.
The Belcher’s Sea Snake Habitat
Where does the Belcher’s sea snake live and in what circumstances do they come into contact with humans?
Unsurprisingly, as a sea snake, the Belcher’s spends the majority of its life in the sea, rarely straying onto land.
However, it isn’t a deep-sea creature either. Rather than opting for an oceanic environment, Belcher’s sea snakes prefer the shallow areas closer to the coastline.
Living in what’s known as the neritic zone of the coastal ocean, this species is never submerged into the inky blackness of the deep waters, instead of swimming in a photic zone where the sunlight consistently breaks through to the ocean floor.
Opting for areas of abundant sea life, Belcher’s sea snakes are found off the northern coast of Australia, in the Timor Sea, and in the waters of the Coral Sea off the coast of Queensland. Further to the north, Belcher’s sea snakes inhabit the shallow seas around the Solomon Islands, although the largest concentration is found in the warmer climes of the Indian Ocean.
The sublittoral zone along the coastline of Papua New Guinea, the Philippines and Indonesia is a veritable wonderland for the Belcher’s sea snake. Coral reefs offer breeding grounds for its prey as well as an ideal place for this less-than-speedy species to find a bite to eat. Sadly, that also means that the Belcher’s, like many other coral-dependent species, may not have its natural habitat to enjoy for very much longer.
With ocean acidification and bioerosion threatening the future of coral reefs throughout the world, the Belcher’s and its neighbors could soon find themselves homeless and hungry in a wasteland of coral skeletons.
What does a Belcher’s Sea Snake Eat?
Sea snakes, in general, aren’t particularly fussy eaters although their diets are purely carnivorous (after all, you don’t need venom to defeat a piece of seaweed). The Belcher’s sea snake is no different in this respect and its diet consists predominantly of fish, fish eggs, eels, and crustaceans. As its top speed is only around 12 mph, it needs the coral as much as protection against its predators, as it needs it for locating suitable hiding places from which to ambush its prey.
The coral reef provides a varied diet for this venomous snake which hunts from the cracks and crevices of its tropical environment. In the open waters, the sea snake has little chance of catching the faster fish, but if it can hide in the shadows and bide its time, the fish have little chance of escape.
Just as the Belcher’s needs an element of surprise to secure itself a meal, so it needs to be on the lookout for eagles and other predators eager to feast on its fleshy delights. Although information about the sea snake’s predators is fairly scarce, sharks have been seen hunting the Belcher’s, with reports of both Grey Reef Sharks and Blacktip Reef Sharks pursuing this stripy prey. Even some large fish, like swordfish, will consider a Belcher’s for breakfast given half the chance, as will the larger eels hunting nearby.
Not all the threats to a Belcher’s sea snake come from underwater, however, and both the Grey-Headed Fish Eagle and the White-bellied Sea Eagle pose serious airborne dangers. Although, in most instances, a predator will opt for a young or injured sea snake as opposed to dicing with death in an assault on a fully functioning adult, even mature Belcher’s are at risk.
Although it was previously believed that sea snakes drank the salty waters of their aquatic habitat, secreting the excess salt using specially designed sublingual glands, recent research suggests that sea snakes have a rather more innovative method of hydration.
While it’s not known if Belcher’s sea snakes perform this same behavior, researchers have established that yellow-bellied sea snakes drink rainwater from the surface of the sea and, during periods of drought, experience similar problems with dehydration as most land-dwelling creatures. For these guys, a period without rain truly is a case of “Water, water everywhere/Nor any drop to drink”.
How Does A Belcher’s Sea Snake Attack its Prey?
Belcher’s sea snakes may be venomous, and they may be hunters by nature, but they’re also surprisingly timid. According to an Associate Professor at the University of Queensland’s School of Biological Sciences, Dr. Bryan Fry, sea snakes “are very gentle animals”.
Despite that, their method of hunting and killing isn’t particularly pleasant. Like most sea snakes, the Belcher’s first bites into the prey with its small fangs and then injects it with its powerful venom.
As the prey performs its brief and futile death throes, so the Belcher’s hold on for dear life waiting for it to quieten, all the while dripping a little more venom into its thrashing body.
Once its prey finally gives up the battle, the sea snake swallows it whole. As Chicago’s Field Museum of Natural History sea snake expert, John C. Murphy, says, “It would not be a nice way to go.”
It makes sense, however, and makes even more when you consider that the Belcher’s sea snake will always swallow its prey headfirst to make it go down a little smoother and avoid any unpleasant spikes or fins from obstructing its course through the digestive system.
The Belcher’s Bite and Fangs
The Belcher’s sea snake bite really isn’t that bad – it’s what it injects during the process that’s the scary part. Snake fangs are divided into three different types, namely, proteroglyphous, solenoglyphous, and opisthoglyphous, with Belcher’s belonging to the first category.
Proteroglyphous fangs are unlike the others in that they are fixed to the jaw and can ‘t be folded back. Resembling the kind of needle a doctor would use to administer an injection, the Belcher’s fangs are short but sharp, in contrast to solenoglyphous fangs which are much longer, reaching up to two inches in length.
The last category of fang, the opisthoglyphous, are similar to the solenoglyphous in that they are also folded back when not in use, but are situated at the back of the mouth, like in the boomslang, making envenomation more complex but, potentially, just as effective.
While a rattlesnake delivers a full dose of venom in the first bite, the Belcher’s sea snake uses a process of progressive envenomation, which is why the rattlesnake will release its victim and yet a Belcher’s will hold on. It’s also why few of the sea snake bites sustained by humans contain a full dose of venom.
When Will a Belcher’s Sea Snake Attack?
As we mentioned earlier, the Belcher’s is a relatively gentle creature and will opt for flight over fight if given the choice.
Most interactions between Belcher’s sea snakes and humans occur underwater and, as the humans are usually wearing wet suits, they are extremely safe as the Belcher’s teeth are so small, they can’t actually get through a wetsuit to the flesh beneath.
The Belcher’s sea snake also has a comparatively small head so it can’t even open its mouth wide enough to bite anything bigger than the average human finger.
Fishermen have a rather rougher time of it when it comes to avoiding envenomation and most Belcher’s sea snake bites have occurred after the creature has become entangled in a fishing net and a helpful human is trying to release it.
Such circumstances aren’t exclusive to the Belcher’s either and last year a young British fisherman died after being bitten by a Black Ringed Sea Snake. Like the Belcher’s sea snake, the Black Ringed’s venom is neurotoxic, meaning it attacks the nervous system, disrupting the chemical signals traveling between the brain and body.
The first symptoms of neurotoxic envenomation are usually evident within a few minutes of the bite having occurred and differ from the symptoms of a tetrodotoxin envenomation, such as that caused by a pufferfish or triggerfish, by attacking the muscles around the eyes first, rather than the muscles around the mouth. Initial indications of a Belcher’s sea snake bite include:
- Blurred vision
- Drooping eyelids (ptosis)
- Aching joints
- Difficulty moving legs
- Sore muscles
- Difficulty speaking or swallowing
- Nausea
- Prolific saliva production
If envenomation was complete, these symptoms will worsen quickly and the victim will start to experience more serious signs, such as an irregular heartbeat and difficulty breathing.
Although it seems as though our muscles automatically perform the functions required to keep us alive, they do so only because our brains tell them to and, as a neurotoxic venom attacks the nerves, so it disrupts that communication. As the muscles gradually stop operating, so does the heart and paralysis of the muscles needed for breathing signals the inevitable end.
Fortunately, in the case of the Belcher’s sea snake, few bites deliver a full dose of venom, so most people survive. Even in the event of a full dose, the victim should make a full recovery if treated promptly with antivenom. Without it, they have just 30 minutes.
Is the Belcher’s Sea Snake the Most Venomous in the World?
Not so long ago, the accepted answer to that question would have been a confident “yes” but, thanks to a new fact-checking site, it seems those claims were just another example of fake news. Scientists and experts on the site Metafact recently disputed these claims and, as a result, a YouTube video discussing the Belcher’s unbeatable toxicity was removed.
While you most certainly don’t want to get bitten by a Belcher’s sea snake, especially if you don’t have an antivenom to hand, it won’t kill you quite as quickly or effectively as the Inland Taipan. These reclusive snakes rarely bite anyone, and yet their fangs contain such a toxic venom, it’s believed one bite would be enough to kill 100 people.
Having said that, the world’s deadliest snakes aren’t necessarily the most venomous, and ascertaining the threat posed by each species depends on several different criteria.
The Belcher’s sea snake’s short fangs and shy personality mean that, although it’s amongst the most venomous, it doesn’t make it into the ranks of the most dangerous.
That honor belongs to the black mamba, which is not only aggressive but also grows to around eight feet long and can strike at an alarming speed from a remarkable distance.
How Venomous Are Belcher’s Sea Snakes?
It wasn’t only YouTube that had the wrong information about the Belcher’s sea snake and its venom, in fact, that confusion has been around since 1996 when a book entitled Snakes in Question: The Smithsonian Answer Book mistakenly labeled the Belcher’s as the world’s most venomous snake.
This confusion arose as a result of inadequate toxicity tests. While the method of testing snake venom is universal and requires identifying the median lethal dose, which varies depending on the testing method used.
For instance, the same amount of venom will work more quickly and effectively if injected directly into the bloodstream, as opposed to intramuscularly or subcutaneously.
In the past, the method was overlooked which made the results of a toxicity test on a Blecher’s sea snake produce inaccurate results suggestive of it being the most toxic snake in the world.
The lower the lethal dose, the more toxic the venom as a smaller volume can have a more devasting effect. Taking that into consideration, the world’s most toxic snake venom belongs to the Inland Taipan which has LD50 toxicity of 0.025.
By comparison, the Belcher’s sea snake’s toxicity has been measured at 0.24mg/kg when injected intramuscularly, making it far less dangerous than its terrestrial counterpart.
One of the other difficulties with the methods currently used to ascertain toxicity is that the Belcher’s sea snake produces very little venom, hence why it holds onto its prey and almost drip-feeds it in.
This makes it difficult for researchers to milk the snake successfully and even more difficult to compare one venom with another and establish relative toxicity.
Even if it’s not the most venomous snake in the world, it’s still well worth thinking about what you might do if bitten by a Belcher’s sea snake, after all, you’ll only have half an hour to act in such circumstances, so having a plan of action already set out could literally be the difference between life and death.
How to Survive a Belcher’s sea Snake Bite
One of the most frightening things about a sea snake bite is that it generally happens, well, out at sea, where there are few doctors, hospitals or sources of anti-venom available. Although we know that, in most instances, a human victim of a Belcher’s doesn’t receive the full dose venom, any bite should be treated as potentially life-threatening.
As we mentioned earlier, with its small mouth and short fangs, the Belcher’s is somewhat limited when it comes to taking on a human being. When caught in a fishing net, however, it can become aggressive, especially if it feels it’s being manhandled, albeit by its potential savior.
In such instances, it’s usually a finger that gets bitten, so the first step is trying to isolate the venom, so it doesn’t get further into the bloodstream and cause more serious symptoms.
A pressure immobilization approach is the best and can be performed following these three simple steps:
- Apply a bandage to the affected limb, wrapping it from the fingers, up the hand, and towards the body. The bandage should be tight enough to restrict blood flow without cutting off the circulation.
- Immobilize the affected limb using a splint or stick
- Remove the bandage every 10 minutes for 90 seconds before reapplying and repeat this for four to six hours after the bite occurred.
Only around 3% of humans bitten by sea snakes actually die, although where full envenomation has occurred, this increases to 25%. Even if the above first aid is performed timeously, it’s not enough to guarantee a full recovery, and antivenom should be administered as quickly as possible.
The sea snake anti-venom is made using horses that are injected with a non-fatal dose of the venom, causing its immune system to react and produce antibodies. These bind themselves to the venom to neutralize it, thereby creating effective antivenom antibodies that can be harvested.
The antivenom should ideally be administered intravenously using a drip set but only if you’re certain than envenomation occurred, as some unpleasant side effects make it potentially dangerous and unpleasant. Those who’ve had previous injections that were prepared using horse blood should be particularly cautious as they are more prone to allergic reactions that can result in anaphylactic shock. Adrenaline should be kept on hand in case of such a reaction and those administering the antivenom should also be on the lookout for the following side effects:
- Elevated temperature
- Itching, hives or a rash at the site of infection
- Swelling of the face, tongue, or lips
- Shortness of breath and breathing difficulties
- Dizziness and fainting
- Chest pains
- Swelling of the glands
Fortunately, in most instances, there is an eight-hour window in which the antivenom can be effective against a Belcher’s sea snake bit, so it should give you enough time to get to a health care professional and receive proper assistance. It’s also reassuring that only about a quarter of bites administered by a Belcher’s sea snake actually envenomate properly, meaning that 75% don’t contain any venom at all.
What to Do if You See a Belcher’s Sea Snake
Most human sightings of these relatively cautious creatures occur when the people are scuba diving or snorkeling. These interactions are generally harmless as the Belcher’s sea snake has little reason to attack and will more likely swim away than attempt to engage in physical contact.
Furthermore, its small head and short fangs mean it’s virtually impossible for a Belcher’s sea snake to get its mouth around anything bigger than a human finger. Nevertheless, as Steve Irwin once said, “you can touch a stick of dynamite, but if you touch a venomous snake it’ll turn around and bite and kill you so fast it’s not even funny”, so not prodding it with your fingers is good advice.
Overall, if you do see a Belcher’s sea snake and it’s not entangled in a net or showing signs of injury, you can enjoy a peaceful sighting without fearing for your life.
Conclusion
While it’s true that a Belcher’s sea snake is venomous enough to kill a human in a matter of minutes, in most cases, it doesn’t present any real threat. Not only is it a relatively timid creature, but it also lacks the tools needed to do any real harm. Having said that, if you’re a keen fisherman and have come face to face with a Belcher’s sea snake snared in your net, you’ll know to approach it with the greatest caution.
The Belcher’s sea snake is not the most venomous in the world but that doesn’t mean you’ll necessarily survive its bite. While only around 75% of its bites envenomate the victim, that’s more than enough given the efficacy of its neurotoxic venom. Attacking the nervous system, neurotoxicity results in muscle failure and causes the victim to stop breathing. While you aren’t in danger of being swallowed whole like the Belcher’s regular prey, the effects of venom are similarly all-engulfing.
The Belcher’s sea snake is relatively rare and comparatively little is known about the species. Living off the coastline of the Philippines, Indonesia, and Australia, it lives a quiet life amongst the coral, hunting and ambushing small fish and crustaceans while avoiding the predatory threats posed by eagles and sharks.
If you’re ever lucky enough to encounter the Belcher’s sea snake, chances are you’ll be in the water with it and the likelihood of physical contact will be extremely limited. In the unfortunate event that you experience a closer encounter with this serpent kind, immediate medical attention should be sought to combat the potentially fatal effects of its neurotoxic venom.
