Article by Tor Pinney                                                                                                                                        Back to List of Tor's Tips

                  

SEA SNAKES

© 1994 Roy Pinney and Tor Pinney - All Rights Reserved

 

Who still believes in sea serpents? Well, the monstrous variety depicted in ancient sailors' lore may not be much on the minds of modern mariners. But cruisers bound for the Pacific and beyond may indeed encounter sea serpents, and potentially deadly ones at that!

Venomous sea snakes mostly inhabit the waters of Australia, Indonesia, Southeast Asia, and India. Some, however, are much more wide-ranging and are found from southern Siberia to the coast of New Zealand and Tasmania, from Cape of Good Hope to Central American Pacific waters. Sailors cruising these waters should be aware (and beware!) of these denizens. Their presence presents a potential danger to swimmers and divers, so it's worth while to have some knowledge of their habits and habitats and of medical treatments available if a crewmember is bitten.

There are possibly more sea snakes in the world than any other kind of snake, and almost all are venomous. Of the more than 50 species (family Hydrophiidae), some are many times more toxic than any known land snake, with venom from 10 to 40 times more potent than that of the cobra!

Sea snakes are air-breathing animals. But evolution has provided them with some advantages over their land-bound kin. Sea snakes have a flattened, rudder-like tail that they use for propulsion and steering. Their nostrils are equipped with a valve-like flap to prevent intake of seawater. A special salt-excreting gland makes it possible for these snakes to drink sea water, and a controllable heartbeat and lungs which are fully three-quarters as long as the snake itself allow them to stay submerged for as long as two (some say eight!) hours.

Sailors cruising the Atlantic or the Mediterranean will not encounter sea snakes. The intolerably cold water of the Atlantic seems to be the single most important reason for their absence there; the Mediterranean is extremely salty and has an unsuitable food supply for the snakes.

Because sea snakes are found in great numbers along the Pacific coasts of Mexico and Central America, naturalists keep lookout for evidence of sea snake entry into the Atlantic Ocean via the Panama Canal. This could result in dire consequences to Caribbean tourism and marine fauna (in the Philippines nets are placed around bathing beaches in an effort to keep out the sea snakes).

However, the likelihood of this trans-oceanic sea snake migration may be small. Much of the Panama Canal is filled with fresh water, reducing the suitable food prey for the snakes. In addition, the sea snake seems to be a passive traveler and usually swims with the currents rather than against them. In the canal, water flows downward from the locks toward the ocean.

Construction of another, sea-level canal through Panama has been proposed. In this case, sea snake entry into the Caribbean is high on the list of possible ecological consequences that have to be considered. Sea snakes have been observed moving up into river mouths and continuing into freshwater lakes. Apparently, water salinity is not physiologically detrimental to them, as long as they can find suitable food.

Most sea snakes feed on fish, fish eggs and eels. Aside from man, the universal predator, there are few animals that attack or regularly feed upon sea snakes. However, they have been found in the stomachs of sharks (along with almost every other edible or inedible thing in the sea). Teleost fish, including the Moray eel, catfish, large grouper, and blue cod may occasionally feed upon sea snakes. Many fish will not eat sea snakes for reasons which are not fully understood, but it is known that these snakes, eaten whole, are capable of inflicting fatal bites on the stomach walls of predator fish. Incredibly, they have actually been reported to then escape through the dead fish's mouth. Some sea birds are also known to prey upon sea snakes.

One of the most astounding observations ever recorded about sea snakes was made by W.P. Lowe in the Strait of Malacca. Near the island of Sumatra and the Malay Peninsula, while on a sea voyage, he saw a long line running parallel to the ship's course about four or five miles distant. As the ship drew nearer to satisfy everyone's curiosity, they were amazed to find that it was composed of a solid mass of sea snakes thickly twisted together. The snakes were orange-red and black - a massive, very poisonous, and uncommon variety known as Astrotia stokesii. Along this line there must have been millions, for it was about ten feet wide and some 60 miles long! Many people have seen snakes of this description, but never in such massed formation.

Eels are often mistaken for sea snakes. Some eels resemble sea snakes so much that they are called "snake eels". But eels are not venomous and have no fangs. They have a pointed (not paddle-like) tail, fins (sometimes hard to see), a gill pouch in the neck area, and are visibly smooth, slippery and slimy due to the usual fish coating of mucous which sea snakes do not have.

How dangerous are sea snakes to people? As with their terrestrial counterparts, most sea snakes will immediately leave the scene when a human approaches. However, in a filmed experiment, one species of sea snake was deliberately molested to provoke attacks. In contrast to the slow, leisurely way a curious snake may approach a diver, these attacking snakes moved with astonishing rapidity - and they were very persistent. They chased fleeing divers for long distances and repeatedly returned to attack after being violently kicked with flippers or pushed aside by a spear gun or snake tongs. Escaping or fending off an attacking sea snake can be an exhausting experience! In one instance, a snake bit the diver (protected by a wet suit) four times before giving up the attack.

The sea snake's bite is relatively painless and, amazingly, a very low percentage of victims actually suffer significant envenomation during an attack. In a census conducted of 17 fishing villages in the northwest Malay Peninsula, it was found that only 25% of those bitten by sea snakes develop any symptoms of poisoning, and of those only a small percentage become critically ill. Additionally, the antivenin (of those species for which it is available) are very effective even if given several hours following the bite. Therefore, antivenin treatment is often delayed for 30 to 60 minutes to see if the victim gets sick. However, for those unlucky few that suffer the full force of a sea snake bite without treatment, convolutions, paralysis, respiratory failure and death can follow.

For Pacific and Indian Ocean cruisers, sea snakes are a potential threat worthy of respect. Although reports of sea snake bites among sailors are rare, some precautions are worth taking. Above all, never molest or provoke a sea snake. Sighting one is no cause for panic, but if you do see them in the water, it's probably wise to refrain from swimming. If you're already in the water, get out or at least move away. If you're attacked by an aggressive sea snake, fend it off while moving directly to your boat or dinghy to get out of the water. A wet suit does offer protection from the snake's bite.

Antivenin is the only currently accepted method of treatment of serious cases of venomous snakebite. Antivenin should never be administered except in a hospital. Keep the victim quiet and at rest, reassure and keep him/her warm. Remove all rings or anything else that might constrict should swelling occur. The most important first aid procedure is to get in touch with a physician who in turn should contact a Poison Control Center for additional advice. Most physicians have had little or no experience with venomous snakebite treatment.

For bites on the toes or fingers, dress the fang marks with a wad of gauze pads and strap in place with surgical adhesive tape. Starting with the hand (or foot), wrap the entire limb with ACE elastic or crepe bandaging. Continue wrapping to several inches above the elbow or knee joint, which will also serve to immobilize the limb. Hold the joint straight - do not bend it when applying the bandage. Do not incise, cut, or suck the bite. Avoid putting ice on the effected part; it may cause frostbite and gangrene. Furthermore, ice dulls the pain, and pain is very important in evaluation of the bite. One folk remedy, administering electro-shock from the coil of an outboard motor, is a dangerous, useless procedure.

As with other natural dangers, mariners in the Pacific and Indian Oceans should exercise caution when sea snakes are around. In most instances, if you leave them alone, they'll leave you alone.

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Sidebar

Snakes for the Gourmet

Over the ages and all over the world, people of both past and present have considered the flesh of snakes to have magical properties, serving as medicine or, in the case of a Manila restaurant, Mariposa de la Vida (Butterfly of Life), as an aphrodisiac. The guest may select a live sea snake from the management's aquarium and have an "exotic" dish prepared from it, to be served at his table. In other parts of the world, some customers would order a live specimen, slit its throat, and drink the blood. Following this aperitif, the still-wriggling snake was diced and eaten raw, with soy sauce.

For the true gourmet, there is an entree called Sea Snake Adobo. The sliced meat is soaked in vinegar, then in soy sauce mixed with a combination of pimento and garlic, for fifteen minutes. The mixture is then boiled in a solution of soda for a half-hour, after which it is drained, fried and garnished with pickles, onions, and tomato al gusto. An alleged aphrodisiac, though to the weak of stomach more likely an emetic, the gall bladder is chugalugged with a glass of wine. In the case of a non-drinker, three dried gall bladders may be blended in coffee and then consumed. Yummy!

Photographs

Color transparencies of sea snakes taken by professional photographers are available from the following New York City photo-agencies:

Animals/Animals: 580 Broadway, NYC 212-925-2110

Peter Arnold Inc: 1181 Broadway, NYC 212-481-1190

Bruce Coleman: 117 E. 24 St., NYC 212-979-6252

Comstock: 30 Irving Place, NYC 212-353-8600

Image Bank: 111 5th Avenue, NYC 212-529-6793

Photo Researchers Inc: 60 E. 56 St., NYC 212-758-3420

The following may be less expensive photo sources:

Paul Freed: 4206 E. Villa, Houston, TX 77017

Dr. John E. McCosker: Steinhart Aquarium, San Francisco, CA

 

About the Authors

Roy Pinney, a naturalist and wild life film producer for television, has had a lifelong interest in snakes. He is president of the New York Herpetological Society and the author of 24 books, including The Snake Book.

Roy often sails with his son, Tor Pinney, who has logged more than 125,000 nautical miles under sail. Tor is author of the books Ready for Sea! and The Best Positive Thinking Book. His boating and travel articles appear often in national magazines in the U.S. and abroad. 

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