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The Top 10 Deadliest Sea Snakes

Larry Slawson received his Master's Degree from UNC Charlotte in 2018. He has a keen interest in biology.

From the yellow-bellied sea snake to the yellow-lipped sea krait, this article ranks the world's deadliest sea snakes!

From the yellow-bellied sea snake to the yellow-lipped sea krait, this article ranks the world's deadliest sea snakes!

The World's Deadliest Sea Snakes

Throughout the world, a number of sea snakes exist that are capable of inflicting serious harm, injury, and death to the human population at large. Although generally considered shy and timid (in comparison to many land-based snakes), sea snakes are renowned for their potent venom that is lethal to humans in only miniscule amounts. From the deadly yellow-bellied sea snake to the black-banded sea krait, this work examines and ranks the world’s deadliest sea snakes. It is the author’s hope that a better understanding (and appreciation) of these fascinating creatures will accompany readers following their completion of this work.

Selection Criteria

In order to select (and rank) the world’s deadliest sea snakes, a number of basic assumptions were necessary for the extents and purposes of this work. First and foremost, each of the following snakes are ranked according to their potential for causing human fatalities. This is a crucial aspect to consider, as sea snakes very rarely attack human beings due to their shy and timid nature. Likewise, a number of sea snakes are known to produce venom in only half of their bites (such as the Belcher’s sea snake), rendering their bites harmless in many cases. As a result, this work examines each of these snakes with a focus on their overall venom toxicity in relation to humans. To accomplish this, average venom yield per snake was calculated, along with the venom’s lethal dosage for humans.

Another factor that is important to consider is the overall fatality rates of snakebite victims. This element is relatively self-explanatory, and involved ranking each of the following snakes with their bite/death ratio applied (when data pertaining to fatality rates could be identified).

Finally, and crucially, the last factor used for ranking each of the following sea snakes is the average time it takes for a bite to produce fatalities in a human. This factor is based on the assumption that no medical treatment (or care) was sought by an individual following a bite. The absence of medical care is crucial for these final criteria to be effective, as the majority of snakebites (worldwide) can be effectively treated by a number of specific antivenoms. This holds true for sea snakes, as both polyvalent and monovalent sea snake antivenoms are available (and highly-effective) against most bites. As such, assuming that no medical treatment was sought by an individual is the only effective means for determining the lethality of each snake’s venom. While these criteria leave a number of potential gaps in the research, the author believes they are the best available means for determining the world’s deadliest sea snake.

How Many Species of Sea Snakes are There?

To date, approximately 69 different species of sea snake have been identified worldwide. These species can be divided into two separate groups of “true sea snakes” (from the Hydrophiinae subfamily), as well as the “sea kraits” (from the Laticaudinae subfamily). The former is related (primarily) to Australian terrestrial elapids, whereas the latter share a common lineage with Asian cobras.

How Dangerous are Sea Snakes?

Sea snakes are among the world’s most venomous animals, with venom toxicity exceeding that of many land-based snakes. As members of the Elapidae family (which includes both the black mamba and inland taipan), sea snakes are well-equipped by mother nature to defend themselves from nearly any adversary (including humans). In spite of their powerful venom, however, most sea snakes are relatively harmless to the human population at large due to their shy and timid nature, non-aggressive behavior, short fangs (which make envenomation difficult), as well as small output of venom. Moreover, it is currently estimated that nearly 80-percent of sea snake bites are “dry,” resulting in no envenomation at all.

As of March 2021, it is currently estimated that approximately 15,000 to 75,000 individuals (mostly fishermen) are bitten by sea snakes each year. Of these, 50-percent of bites are inflicted by the venomous beaked sea snake. However, due to the high rate of “dry” bites and the widespread distribution of antivenom, only 3-percent of these bites result in fatalities (Phillips, 60).

10 of the World's Deadliest Sea Snakes

  • Yellow-Bellied Sea Snake
  • Hardwicke’s Sea Snake
  • Zweifel’s Beaked Sea Snake
  • Black-Banded Sea Krait
  • Yellow-Lipped Sea Krait
  • Ornate Reef Snake
  • Olive Sea Snake
  • Beaked Sea Snake
  • Dubois’ Sea Snake
  • Belcher’s Sea Snake
The yellow-bellied sea snake.

The yellow-bellied sea snake.

10. Yellow-Bellied Sea Snake

  • Average Size: 2.2 to 2.9-feet
  • Geographical Range: Indo-Pacific Region, Costa Rica, Southern California, and Northern Peru
  • Aggression Level: Low
  • Danger to Humans: Moderate
  • Conservation Status: “Least Concern” (Population Stable)

The yellow-bellied sea snake is a highly-venomous sea snake that was first discovered in the 1700s. Endemic to West Coast of North America, Northern South America, Southeast Asia, and the coasts of Africa, the yellow-bellied sea snake is an incredibly dangerous species with the ability to harm and kill humans with relative ease. Reaching only 35-inches at maturity, the animal is incredibly small, with valved nostrils (to keep out seawater), and a paddle-like tail to aid in swimming. As its name implies, the snake can be easily identified by onlookers due to its yellow underbelly, and dark brown scalation.

The yellow-bellied sea snake spends much of its time in the water, but can be occasionally seen on beaches when washed ashore. The snake is fully adapted to aquatic life (rendering land-based activities nearly impossible). As such, the snake primarily feeds on pelagic fish within its natural habitat. Using ambush tactics for hunting, the yellow-bellied snake is known to rapidly “lunge” towards fish, delivering a deadly dose of venom through its sharp jaws that subdues prey within seconds.

Yellow-Bellied Sea Snake Bite Symptoms and Treatment

The yellow-bellied sea snake possesses an incredibly potent venom (comprised of several neurotoxins and isotoxins) that is lethal in only small amounts. And while the average venom yield is only 1 to 4 milligrams (per bite), the presence of neurotoxins and two separate isotoxins make their venom incredibly dangerous to humans and animals. This is due to the fact that the yellow-bellied sea snake’s venom directly attacks the muscular-skeletal system, resulting in widespread paralysis, renal damage, and myoglobinuria in a short span of time. Following envenomation, symptoms usually begin within minutes of a bite, and include drooping eyelids, lethargy, nausea, vomiting, muscle pain (and weakness), as well as abdominal cramps. Assuming full envenomation has occurred, death is common in the absence of medical care and attention.

Bites from a yellow-bellied sea snake are considered a life-threatening emergency that require immediate medical treatment for survival. To date, the most effective treatment option for this species involves multiple doses of “Commonwealth Serum Laboratories Sea Snake Antivenom.” Tiger snake and other polyvalent antivenoms have also been effective against yellow-bellied sea snake bites, but are only used by medical professionals when the former is unavailable. Following administration of the antivenom, palliative care, pain mitigation therapy, and intravenous fluids (to maintain hydration) are often incorporated into treatment plans. This is sometimes coupled with dialysis in order to prevent further injury to the kidneys. To date, only one human has died from a yellow-bellied sea snake in recent years. Nevertheless, this is a very dangerous snake that should be avoided whenever possible.

The infamous Hardwicke's sea snake..

The infamous Hardwicke's sea snake..

9. Harwicke's Sea Snake

  • Average Size: 2.4 to 3.3-feet
  • Geographical Range: Persian Gulf, Indian Ocean, South China Sea, and Pacific Ocean
  • Aggression Level: Moderate
  • Danger to Humans: Moderate
  • Conservation Status: Unknown (Insufficient Data)

The Hardwicke’s sea snake (also known as the “spine-bellied sea snake”) is a species of highly-venomous snake from the Elapidae family. Found throughout the temperate waters of the Persian Gulf, Indian Ocean, South China Sea, as well as portions of the Pacific, the Hardwicke’s sea snake is an incredibly dangerous animal capable of severely injuring (and killing) human bystanders with ease. As with many sea snake specimens, the snake can be easily identified due to its short body length, stout neck and head, wide nostrils, as well as their unique olive or dark grey coloration that is relatively uniform. Occasionally heads may take on a distinct olive or black coloration, with yellow markings. However, this is usually only seen in rarer circumstances.

Within its natural habitat, the Hardwicke’s sea snake is commonly found in more shallow (coastal) waters, as this area provides the snake with ample prey to consume on a daily basis. As of March 2021, very little is known about the snake’s dietary preferences; however, small fish are believed to be its primary source of food.

Hardwicke’s Sea Snake Bite Symptoms and Treatment

To date, almost nothing is known about the venom of the Hardwicke’s sea snake. Nevertheless, numerous studies undertaken by researchers over the last decade have indicated that the snake’s venom is likely comprised of both neurotoxins and myotoxins (similar to other sea snakes). Combined, these two toxins deliver a coordinated attack on an individual’s muscular-skeletal and central nervous systems, respectively. Following envenomation, symptoms usually begin within minutes and include dizziness, migraine headaches, stomach pain, as well as muscle weakness and pain. Without rapid medical treatment, the progression of venom throughout the bloodstream only enhances these symptoms further, leading to paralysis, hallucinations, as well as hysteria. In its final stages, death is common due to cardiac arrest (heart failure), or from complete respiratory collapse (leading to death by suffocation).

As with most sea snakes, a bite from the Hardwicke’s sea snake should be classified as a life-threatening emergency that requires immediate medical attention. Receiving prompt medical treatment, however, can be extremely difficult with this species due to its remote location in the wild. For this reason, many individuals often die before they ever reach a hospital or facility. In the event that rapid care is able to be achieved though, the first round of treatment for a Hardwicke’s sea snake bite is pressure immobilization of the wound site, followed by several rounds of Polyvalent Sea Snake Antivenom. This is generally followed up with hospital admittance, substantial bed rest, as well as the administration of intravenous fluids.

Fortunately, bites from the Hardwicke’s sea snake are exceptionally rare, with only a handful of incidences reported over the last century. Nevertheless, this is an incredibly dangerous species that has proven itself to be quite deadly when encountered in the wild. As such, individuals should avoid approaching the Hardwicke’s sea snake at all costs.

Zweifel's beaked sea snake.

Zweifel's beaked sea snake.

8. Zweifel's Beaked Sea Snake

  • Average Size: 4 to 5.1-feet
  • Geographical Range: Papua New Guinea and Australian Coast
  • Aggression Level: Low
  • Danger to Humans: Moderate
  • Conservation Status: Unknown (Insufficient Data)

The Zweifel’s beaked sea snake (also known as the “Sepik beaked sea snake”) is a species of deadly snake from the Elapidae family. Originally believed to be a different species known as the “Asian beaked sea snake,” DNA testing successfully demonstrated that the Zweifel’s beaked sea snake is actually a separate species. Endemic to the temperate waters of Papua New Guinea and the Australian coast, this snake is capable of reaching nearly 5-feet in total length at maturity (making it one of the largest sea snakes in the world). They can be easily identified by their elongated heads, rounded snouts, and grayish-brown coloration.

Characterized as a relatively rare and uncommon species by researchers, the Zweifel’s beaked sea snake is commonly found living in shallow waters near estuaries and various river mouths. Within their natural habitat, the snake feeds primarily on smaller fish, with some specimens even attacking large catfish on occasion. At present, some researchers have hypothesized that the Zweifel’s beaked sea snake is also cannibalistic (feeding on other animals of its kind); however, this behavior has not been observed empirically.

Zweifel’s Beaked Sea Snake Bite Symptoms and Treatment

As with all elapids, the Zweifel’s beaked sea snake is an extremely venomous snake with a venom that is comprised of both neurotoxins and myotoxins. Although most bites are relatively painless (and may even go unnoticed by victims), the toxic properties of the venom often begin to showcase themselves within a few hours of a bite. Following a bite, symptoms usually include muscle pain and weakness, dizziness upon standing, breathing difficulties, as well as severe fatigue. Migraines and paralysis of the extremities has also been reported by victims, particularly when the venom begins to take greater control of an individual’s body and starts to affect internal organs. Without treatment, death is common, with respiratory failure being the primary cause of death (leading to suffocation).

A bite from the Zweifel’s beaked sea snake is a life-threatening emergency that requires immediate treatment for survival. Even when a “dry” bite is suspected, individuals should still seek rapid medical care to rule out the possibility of envenomation. As with most sea snake bites, several rounds of Polyvalent Sea Snake Antivenom remains the primary treatment option for a bite. This is followed by bedrest, intravenous fluids, as well as pain mitigation therapy. In cases of severe envenomation, intubation and respiratory support may also be necessary for breathing support. With immediate treatment, the prognosis for a Zweifel’s beaked sea snake bite is generally good, with many individuals making a full recovery in time.

The deadly black-banded sea krait.

The deadly black-banded sea krait.

7. Black-Banded Sea Krait

  • Average Size: 2.3 to 2.9-feet
  • Geographical Range: Western Pacific Ocean
  • Aggression Level: Moderate
  • Danger to Humans: Moderate
  • Conservation Status: “Near Threatened” (Population in Decline)

The black-banded sea krait (also known as the “Chinese sea snake”) is a species of highly-venomous snake from the Elapidae family and Laticaudinae subfamily, respectively. Endemic to the warm waters of the Western Pacific Ocean (near China, Japan, and Okinawa), the black-banded sea krait is currently listed as “near threatened” by the IUCN due to declining population numbers. Characterized as a relatively aggressive species, the snake is incredibly dangerous to human beings with the potential to kill an adult human within minutes of a bite. Often mistaken for the Belcher’s sea snake (due to similar markings), the black-banded sea krait can be easily identified by its short head, paddle-like tail, as well as its signature black bands.

As a nocturnal species, the black-banded sea krait is rarely seen during the day, and spends much of its time near coral reefs that provide it with ample cover from predators, while simultaneously supplying the snake with an almost unlimited source of food. Little is currently known about the black-banded sea krait’s dietary preferences; however, it is currently theorized that small fish are its primary source of food, along with the occasional eel.

Black-Banded Sea Krait Bite Symptoms and Treatment

As of 2021, very little is currently known about the black-banded sea krait’s venom. Nevertheless, most experts agree that the venom is comprised (primarily) of highly-toxic neurotoxins that attack the nervous systems of their victims. Following a bite, symptoms usually begin within minutes and include nausea, muscular pain and weakness, as well as dizziness upon standing, and migraine headaches. Without rapid treatment, convulsions and hallucinations are common as neurotoxicity occurs, followed by paralysis, cardiac arrest, and eventually death.

A single bite from the black-banded sea krait is believed to be approximately 10 times as potent as a standard rattlesnake species (toxinology.com). Producing approximately 10 to 15 milligrams of venom per bite, it is estimated that only a fraction of this amount is necessary to produce lethal effects. For this reason, bites from a black-banded sea krait should be considered life-threatening emergencies that require immediate treatment for survival. As with most sea snake bites, standard treatment involves rapid administration of Polyvalent Sea Snake Antivenom, followed by close observation, and intravenous fluids (to maintain hydration levels). Close observation of the heart and blood pressure are also necessary for bites, as the neurotoxins from this species are known to result in cardiac failure in severe cases.

The yellow-lipped sea krait (washed ashore).

The yellow-lipped sea krait (washed ashore).

6. Yellow-Lipped Sea Krait

  • Average Size: 3 to 6-feet
  • Geographical Range: Indian Ocean and Western Pacific
  • Aggression Level: Low
  • Danger to Humans: Moderate
  • Conservation Status: “Least Concern” (Population Stable)

The yellow-lipped sea krait (also known as the “banded sea krait,” or “colubrine sea krait”) is a species of highly venomous sea snake from the Elapidae family. Endemic to the tropical waters near India and the Western Pacific, the yellow-lipped sea krait possesses an extremely potent neurotoxic venom that is fatal to humans in only small doses. As their name implies, the animal can be easily identified by its yellow snout (hence, “lips”), bluish body, unique stripes (black), as well as their paddle-like tail that aids in swimming. They are also quite long for a sea snake species, and have been known to reach nearly 6-feet in length at maturity.

Within its natural habitat, the yellow-lipped sea krait is commonly found near reefs and various rocky outcroppings. As a semiaquatic species, however, the snake is also capable of living on land, where it spends a great deal of its time. Very little is currently known about the dietary preferences of this species. Nevertheless, most experts believe that one of the primary food sources for the yellow-lipped sea krait is eels and small fish. This includes both conger eels and moray eels, which are relatively common in their distribution area.

Yellow-Lipped Sea Krait Bite Symptoms and Treatment

The venom of a yellow-lipped sea krait is incredibly powerful, and is comprised of a potent neurotoxic protein known to disrupt neural synapses in bite victims. Following a bite, symptoms usually begin within moments, and include breathing difficulties, paralysis of the extremities, dizziness, and extreme lethargy. Muscle weakness and convulsions are also cited amongst victims, with convulsions often occurring in quick succession before death. Cyanosis (a discoloration of the skin and mucous membranes) has also been described by patients. To date, fatal hypertension, respiratory failure, and cardiac arrest are the most common causes of death from the yellow-lipped sea krait’s venom.

Bites from the yellow-lipped sea krait are considered life-threatening, and require immediate medical treatment for survival. As with most venomous snakes, the first line of treatment involves several rounds of Polyvalent Sea Snake Antivenom (dependent upon the venom yield of the bite). This is followed by intravenous fluids for hydration, along with bedrest and painkillers. In severe cases, intubation may be necessary to aid in breathing. Fortunately, bites from this species are remarkably low due to their low aggression level and general shyness towards humans. Nevertheless, this is a species of sea snake that should be avoided at all costs, as fatality rates (while unknown) are expected to be high.

The ornate reef snake.

The ornate reef snake.

5. Ornate Reef Snake

  • Average Size: 3 to 3.2-feet
  • Geographical Range: Western Pacific, Western Australia, Indian Ocean
  • Aggression Level: High
  • Danger to Humans: Moderate
  • Conservation Status: Unknown (Insufficient Data)

The ornate reef snake is a species of highly-venomous snake from the Elapidae family. Endemic to the coastal waters of Western Australia, the Indian Ocean, and the Western Pacific, the ornate reef snake is an incredibly dangerous (yet shy) species renowned for their heavy build, cylindrical appearance, and beautiful scalation. They can be easily identified by their greyish-blue coloration, relatively long length (approaching 3.2-feet at maturity), as well as their overlapping body scales that aid in swimming.

As with many of the sea snakes on this list, the ornate reef snake spends much of its time along coastal regions where water is relatively shallow. From here, the snake hunts predominantly in reefs (as its name implies), or in rocky outcroppings where prey is abundant. Very little is currently known about this specie’s dietary preferences, due to a lack of empirical observation in the wild. Nevertheless, most researchers agree that small fish appear to be its primary source of food.

Ornate Reef Snake Bite Symptoms and Treatment

To date, almost nothing is currently known about the Ornate Reef Snake’s venom properties. Nevertheless, it is believed to possess powerful neurotoxins that unleash a deadly assault on a bite victim’s cardiovascular, muscular-skeletal, and central nervous systems. Following a bite, symptoms can begin within moments, and include paralysis of the extremities, muscle weakness and pain, migraine headaches, as well as dizziness and hallucinations. Convulsions are also common, and are generally followed by labored breathing and complete respiratory failure (or cardiac arrest) if left untreated.

As with all sea snake bites, envenomation from an ornate reef snake should be deemed a life-threatening emergency that requires immediate treatment for survival. Polyvalent Sea Snake Antivenom remains the primary treatment option for doctors, followed by bedrest, pain mitigation therapy, as well as intubation in cases involving breathing issues. Fortunately, attacks from this species are exceedingly rare due to its remote habitat and distribution. Nevertheless, individuals should exercise extreme caution when entering the ornate reef snake’s environment, as a single bite from this species is capable of killing an adult human or child with ease.

The olive sea snake in its natural habitat.

The olive sea snake in its natural habitat.

4. Olive Sea Snake

  • Average Size: 3.2 to 6.4-feet
  • Geographical Range: Indian Ocean, Western Pacific, Northern Australia
  • Aggression Level: Moderate
  • Danger to Humans: High
  • Conservation Status: “Least Concern” (Population Stable)

The olive sea snake (also known as the “olive-brown sea snake,” or the “golden sea snake”) is a species of highly-venomous snake form the Elapidae family. Endemic to the coastal waters of the Indian Ocean, Western Pacific Ocean, and parts of Northern Australia, the olive sea snake is an incredibly dangerous species with a venom that is (drop-for-drop) the most toxic of all sea snakes. As a relatively large snake, the animal has been observed to grow upwards of 3.2 to 6.4-feet at maturity. They are also renowned for their remarkable light sensitivity, and spend much of their time in the dark (hiding from potential predators). They can be easily identified by their paddle-like tail, long length, brownish-purple scalation, as well as their white (cream) colored underbellies.

Within its natural habitat, the olive sea snake spends much of its time in coastal (shallow) waters in the vicinity of coral reefs (including the world famous “Great Barrier Reef”). Using the small crevices and coves that are abundant within these structures for protection, the snake actively hunts a variety of prey, including crustaceans, small fish, and fish eggs. Due to their remarkable size, however, a number of olive sea snakes have been observed consuming medium to large-sized fish in recent years, as well as various prawns and crabs.

Olive Sea Snake Bite Symptoms and Treatment

Although bites from the olive sea snake are rarely recorded, a number of fatal encounters have been registered throughout history in regard to fishermen, swimmers, and divers especially. Containing a powerful series of neurotoxins and enzymes, the olive sea snake’s venom delivers a catastrophic attack against a victim’s body, paralyzing the muscles and cardiovascular system rapidly. Symptoms from a bite usually begin within minutes and include dizziness (lightheadedness), migraine headaches, paralysis of the extremities, muscular pain and weakness, as well as extreme lethargy. Without medical treatment, hallucinations and convulsions are common, followed by complete respiratory failure once the venom takes hold of the lungs.

Without appropriate medical treatment, bites from a olive sea snake are considered life-threatening emergencies with low survival rates. Although Polyvalent Sea Snake Antivenom is often life-saving in its application to victims, it is difficult to administer in a timely manner due to the remote nature of the snake’s habitat. More often than not, most individuals die before they can even reach a medical facility. For individuals that do manage to reach a hospital, however, most go on to recover from their bite within a few weeks or months of bedrest, intravenous fluids, and supportive care.

The deadly beaked sea snake.

The deadly beaked sea snake.

3. Beaked Sea Snake

  • Average Size: 2.6 to 5.1 feet
  • Geographical Range: Arabian Sea, Persian Gulf, and Southeast Asia
  • Aggression Level: High
  • Danger to Humans: High
  • Conservation Status: “Least Concern” (Population Stable)

The beaked sea snake (sometimes referred to as the “common sea snake” or “hook-nosed sea snake”) is a species of highly venomous snake form the Elapidae family. Regularly classified as one of the world’s deadliest sea snakes, the beaked sea snake is an incredibly dangerous animal that is responsible for a number of bites and human deaths each year. Endemic to the Arabian Sea, Persian Gulf, and parts of Southeast Asia, this deadly snake can be easily identified due to its long length, dark grey coloration, as well as its white underbelly that contrasts sharply with the rest of its body (Owlcation.com).

From within its natural habitat along the coastal regions of the Arabian Sea and Persian Gulf, the beaked sea snake spends much of its time near rocks and underwater foliage to protect itself from predation. From this vantage point, the snake is afforded a wide array of prey, with small fish being the primary source of food. With an ability to spend upwards of 5 hours underwater before needing to resurface for air, the beaked sea snake is able to take its time hunting in either shallow or deeper waters (upwards of 100 meters).

Beaked Sea Snake Bite Symptoms and Treatment

The beaked sea snake possesses a deadly venom that is comprised of numerous neurotoxins and myotoxins. And while the average venom yield for this particular species is relatively low for snakes (reaching only 7.9 to 9 milligrams per bite), the deadly toxins are fatal to humans at only 1.5 milligrams. This, in turn, makes the beaked sea snake an incredibly dangerous species with the capability of killing a healthy human with ease.

Following envenomation, bite symptoms generally begin quickly and involve migraine headaches, abdominal cramps, vomiting, and nausea. This is usually followed by extreme diarrhea, vertigo, and convulsions once the venom takes hold of the body’s vital organs. Without treatment, kidney failure, cardiac arrest, or complete respiratory failure are common, leading to death.

Bites from a beaked sea snake are considered a life-threatening emergency that requires immediate treatment for survival. Treatment is often difficult to achieve, however, due to the snake’s remote location. As a result, death is common amongst individuals as they are unable to be hospitalized in a timely manner. Assuming medical treatment can be sought though, standard treatment for a beaked sea snake bite includes numerous doses of CSL Sea Snake Antivenom, followed by intubation (respiratory support), as well as the administration of intravenous fluids (to maintain hydration levels). Occasionally, dialysis may also be implemented as a means to protect the kidneys from harm.

To date, overall fatality rates for the beaked sea snake are not currently known. However, it is currently estimated that the snake is responsible for nearly 50-percent of all snake bites annually, and 90-percent of the sea snake fatalities reported each year (toxinology.com).

The Dubois' sea snake (washed ashore).

The Dubois' sea snake (washed ashore).

2. Dubois' Sea Snake

  • Average Size: 2.6 to 4.8 Feet
  • Geographical Range: Papua New Guinea, Coral Sea, Timor Sea, Arafura Sea, and Indian Ocean
  • Aggression Level: High
  • Danger to Humans: Extreme
  • Conservation Status: “Least Concern” (Population Stable)

The Dubois’ sea snake (also known as the “reef shallows sea snake”) is a species of deadly snake from the Elapidae family. Endemic to the coastal waters of Australia and Southeast Asia, the Dubois’ sea snake is an incredibly dangerous species that has the capacity to seriously harm (and kill) humans with a single bite. The animal can be easily identified by onlookers due to its long length, broad head, fin-like tail, as well as tannish complexion that is marked by a series of dark brown crossbands.

The Dubois’ sea snake is commonly found throughout the coastal regions of Australia and the Indian Ocean in regions that contain large swathes of underwater seaweed (Owlcation.com). Capable of living in depths of nearly 262-feet (80 meters), the snake is afforded numerous opportunities for feeding that remain out of reach for the majority of sea snakes. Common prey includes moray eels, small fish, and various bottom dwellers. To date, the snake is believed to primarily be active during the dawn and dusk hours, rendering it a crepuscular species.

Dubois’ Sea Snake Bite Symptoms and Treatment

The Dubois’ sea snake’s venom is one of the most potent in the entire world, and is comprised of several postsynaptic neurotoxins, myotoxins, nephrotoxins, as well as cardiotoxins. Taken together, these compounds deliver a devastating attack on an individual’s entire bodily structure. Within minutes of a bite, individuals can expect to suffer severe headaches, nausea, intense bouts of vomiting, as well as diarrhea, abdominal cramping, and dizziness. Paralysis of the extremities is also common with a Dubois’ sea snake bite, along with convulsions as the venom progresses throughout the victim’s bloodstream to the internal organs. Complete kidney failure, cardiac arrest, and collapse of the respiratory system are usually cited as the three leading causes of death (when left untreated).

Bites from a Dubois’ sea snake are fatal in 100-percent of cases if left untreated. As such, immediate medical treatment is necessary to prevent death. This is often problematic, however, as the snake’s habitat (in the middle of the Arabian Sea and Persian Gulf) make rescue unlikely for most. For these reasons, fatalities are common amongst victims. Nevertheless, in cases where hospitalization can be achieved, CSL Sea Snake Antivenom remains the number one treatment for a Dubois’ sea snake bite. Following admittance to a medical facility, individuals are also likely to receive respiratory support (via intubation and/or ventilation), and possible dialysis to protect the kidneys from shutting down (Owlcation.com). This is generally followed by palliative care, pain mitigation therapy, as well as the administering of intravenous fluids (for hydration purposes).

In spite of these advances in treatment, however, long-term complications from a Dubois’ sea snake bite are common amongst survivors, with muscle pain, weakness, and severe organ damage being cited as common issues. For these reasons, the Dubois’ sea snake is an animal that should be avoided at all costs by humans! Failure to heed this warning could result in serious harm or death.

The highly-venomous (and dangerous) Belcher's sea snake.

The highly-venomous (and dangerous) Belcher's sea snake.

1. Belcher's Sea Snake

  • Average Size: 1.5 to 3.3-feet
  • Geographical Range: Indian Ocean, Gulf of Thailand, Papua New Guinea, Indonesia, Philippines, and Australian Coast
  • Aggression Level: Low
  • Danger to Humans: Extreme
  • Conservation Status: Unknown (Insufficient Data)

The Belcher’s sea snake (occasionally referred to as the faint-banded sea snake) is an elapid species renowned for its extremely toxic venom. Often referenced by scholars as being the most venomous snake in the world, the Belcher’s sea snake maintains a relatively shy and timid temperament (making it a relatively docile animal that tries to avoid human contact whenever possible). The snake is commonly found in the Indian Ocean, Gulf of Thailand, as well as the coastal waters of Papua New Guinea, the Philippines, Indonesia, and Australia. They can be easily identified by onlookers due to their slender body, small size (reaching upward of 3.3-feet at maturity, as well as their chrome-like body that is highlighted by green crossbands (Owlcation.com).

Within their natural habitat, the Belcher’s sea snake is commonly found living in tropical reefs where they are afforded a great variety of prey. Capable of holding their breath for upwards of eight hours at a time, the snake typically hunts through ambush tactics, using the natural crevices and concealment provided by tropical reefs to their advantage. To date, it is believed that this species primarily consumes small fish and the occasional eel.

Belcher’s Sea Snake Bite Symptoms and Treatment

The Belcher’s sea snake possesses a highly toxic venom that is capable of killing an adult human in less than 30 minutes. Research has demonstrated time and again that the snake’s venom is nearly 100-times the overall strength of an inland taipan, making each bite a life-threatening event. Fortunately for most individuals, the snake’s mild temperament makes human bites a relatively rare occurrence in the wild. Likewise, scientific studies have shown that the Belcher’s sea snake is capable of controlling its overall venom secretion, and releases venom in only 25-percent of its bites.

Current research on the Belcher’s sea snake indicates that the animal possesses high levels of both neurotoxins and myotoxins in its venom. A single drop is thought to be strong enough to kill over 1,800 people with ease. Following envenomation, symptoms usually begin rapidly and include nausea, stomach cramps, vomiting, and diarrhea. Other common symptoms include migraine headaches, dizziness, and convulsions once the snake’s neurotoxins begin to take hold on the victim’s body. This is followed by paralysis, muscle weakness (and impairment), as well as extreme hemorrhaging, hallucinations, and hysteria. Without treatment, death usually follows within minutes due to complete respiratory failure (suffocation) or kidney failure.

Bites from the Belcher’s sea snake are life-threatening events that require immediate treatment for survival. To date, the most common treatment for a bite includes several rounds of Polyvalent Sea Snake Antivenom, combined with pain-mitigation therapy, intravenous fluids, as well as bed rest. In cases involving acute injury to the kidneys, dialysis may also be implemented to prevent complete renal failure from occurring. Taken together, these treatment options are often effective for most individuals if medical treatment is sought rapidly. However, long-term complications are common from Belcher’s sea snake bites, with some issues (such as muscle weakness and fatigue) becoming lifelong issues. For these reasons, the Belcher’s sea snake is easily the deadliest (and most dangerous) species of sea snake in the world.

What to do (and not do) in the event of a snake bite.

What to do (and not do) in the event of a snake bite.

Works Cited

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Larry Slawson

Comments

Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on October 06, 2021:

Thanks for sharing all this much information.

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