The Snakes of Paradise

by Howard Hall

©Howard Hall

   Ramon left his tiny Philippine fishing village on the southwest coast of Cebu an hour before dawn. With his partner Edwardo, he paddled his delicate outrigger canoe west. It would take them over two hours to reach Cervera Shoals ten miles distant. No rock or buoy marked the location of the shoals. The summit of the seamount rose from the depths of the Bahol straits to within forty feet of the surface but remained invisible to passing boats. But Ramon had been there before and with casual ease he lined up three range bearings on the distant shore and declared to Edwardo that they had arrived. He then donned his diving equipment, which consisted solely of a pair of hand-made wooden goggles, and looked over the side.

   What he saw when he looked over the side of his canoe probably surprised him. For there was I kneeling on the seamount, covered with neoprene, SCUBA tanks, and other paraphernalia which permitted me to swim underwater only slightly less gracefully than Ramon did wearing no equipment save his wooden goggles. After giving me a rather lengthy examination he turned his attention to his purpose for coming to Cervera Shoals - snakes.

    Ramon didn't have to search long. The tiny summit of the seamount was alive with sea snakes. I could see dozens of them in almost any direction I looked and in some places their density exceeded a half dozen per square meter. Most were three or four feet long and had dramatic black and white vertical bands. They had small heads with very dark black eyes, and their tails were flattened vertically into paddles.

   Everywhere I looked I saw snakes sleeping under overhanging corals, snakes searching in holes for food, snakes dashing to the surface to breath, and snakes entwined around each other in courtship. When I looked down I saw snakes swimming around my knees and over the backs of my legs. Once, I noticed a snake as it swam up over my shoulder, around my neck and had a look in my facemask before going on to examine my hair.

  That I permitted my body to be explored by sea snakes may seem a bit unwise especially when one considers just how venomous these creatures are. All of the more than fifty species of sea snakes evolved from the ancestors of cobras and kraits. Nearly all are venomous and most carry venom several times more deadly than any species of land snake. The venom attacks the nervous system causing muscular paralysis; the severity of which is determined by the amount of venom injected and the location of the bite. Death often results from cardiovascular and pulmonary failure. But despite the sea snake's terrible potential, unprovoked attacks on divers are essentially unheard of. And most species of sea snake seem to hesitate using their venom in self-defense. Perhaps this is because sea snakes have so few natural predators.

   So why are sea snakes so venomous? They don't strike their prey in the open and then back off waiting for a sudden death like terrestrial pit vipers do. Most sea snakes search for their prey in holes and crevices. By poking their long necks into these hiding places the snakes can trap their prey inside. A snake then bites the trapped fish and continues to block the escape while the fish succumbs to the venom. When many species of fish are trapped in holes by predators they erect their spines to prevent being removed. Perhaps the snakes' venom is necessary to cause the muscles holding these erected spines to relax. In addition, fish are cold-blooded animals and have less efficient circulatory systems than mammals do. For this reason venoms act less quickly on fish than on rodents. This too may explain the sea snake's extreme toxicity.

   Despite the strength of the sea snakes' venom, their feeding mechanism is not a sudden process. I watched one snake enter a hole and spend nearly a half-hour working to extricate a large damsel fish it had killed. The fish had to be removed from the hole and turned around so that the snake could swallow it head first. (Sharp spines prevent a fish from being swallowed tail first). Finally, the snake succeeded in pulling the fish free of the hole, but it had used too much energy and needed air. So the snake left the fish on the bottom and began swimming forty feet to the surface. Under normal activity, a sea snake may hold its breath for two hours or more. When the snake is inactive or asleep, some scientists think that they absorb enough oxygen directly through their skin to permit them to remain submerged indefinitely. But when the snake is engaged in strenuous activity, they may need air after only minutes.

  When the snake swam to the surface I felt certain that the damselfish would become a meal for a crab or another scavenger. I never thought the snake would attempt to find its prey again especially after drifting ten yards or more in the current as it swam to the surface and back down to the bottom. But what happened next surprised me. The snake reached the bottom thirty feet down current and immediately swam back through a maze of coral to the damsel fish which was soon swallowed whole. Sea snakes have very poor eyesight and so this snake must have found its way using an extremely keen sense of smell.

©Howard Hall

In Southeast Asia hundreds of people die from sea snake bites each year. Despite this alarming statistic, sea snakes are not evil, aggressive serpents that strike out at humans with little or no provocation. On the contrary, sea snakes are among the most docile of reptiles. When threatened, harassed, or even abused, sea snakes will usually expend most of their strength in an effort to escape their tormentor before biting as a last resort. Certainly, this tolerance to abuse varies from species to species. But no species of sea snake will bite a human unless carelessly or unknowingly manhandled.

   The fatalities in Southeast Asia generally result from people accidentally standing on snakes in shallow turbid water or fishermen attempting to remove them from nets. A SCUBA diver is at little risk unless he intentionally manhandles a snake or unintentionally pins one to the bottom with his hand or knee. In a weightless condition, underwater, the latter is rather unlikely. So despite the presence of sea snakes swimming through my hair on Cervera Shoals, I felt unthreatened. Of course, I made some minor effort to avoid making any of them unhappy.

   A courtship ritual resulted whenever two snakes encountered each other. The pair would swim side by side and then entwine around each other. One snake would become infatuated with the back of the other's head and seemed to enjoy licking it with a long forked tongue. Often these displays were short lived. Perhaps one member of the pair was not in the mood. Or perhaps they discovered they were of the same sex (although I can't quite imagine how). Sometimes the display would go on for extended periods often exceeding the time provided by my limited air supply.

  This mating aggregation was the reason Ramon had paddled so far to reach Cervera Shoals. He could collect more snakes here in a day during the breeding season than during a month of hunting other areas. So for the next few weeks, Ramon and a few other snake divers will work the Shoals hard before returning to their normal occupations as subsistence fishermen.

   When Ramon looked over the side of his boat he was not just looking for a sea snake, he was looking for especially heavy concentrations of sea snakes. Once satisfied, he took a few deep breaths and dived in. He easily reached the bottom at forty or fifty feet pulling slowly and deeply with his arms. As soon as he achieved the bottom he began gathering snakes.

   So great were the numbers of snakes on the bottom that Ramon had no difficulty collecting five or six during the sixty seconds he remained submerged. He caught the snakes with his right hand and carried them with his left. As he caught each additional snake, he would carefully transfer it from his right hand to his left without releasing his hold on its neck. At the same time he maintained his grasp on the necks of the other four or five snakes already becoming very unhappy in his left hand. When I looked closely at his serpent-filled fist I noticed that some of the snakes had their mouths open and seemed upset enough to bite, but most were still using all their strength just trying to swim free.

   In the late afternoon, Ramon paddled back to his village with the floor of his boat alive with sea snakes. Once ashore, he will kill the reptiles and then skin them. These skins will be sold to a tannery in Manila for the equivalent of about two cents each. In some parts of Indonesia sea snakes are eaten as a dish best described as sea snake sausage. But in the Philippines a taste for the reptiles has yet to develop. Once skinned, the remainder of the snake is just waste.

   In the early 1970's a market developed in the Philippines for sea snake skin shoes, belts, handbags, and other leather goods. Soon afterwards an export market developed in the United States and Europe. The demand for sea snake skin rocketed. So did the supply.

   Part of the reason that I had gone to the Philippines, along with film producer Lenora Carey, was to film sea snakes for a BBC program. Our first destination was Gato Island. Gato was famous for the spectacular number of sea snakes that accumulated there during the mating season. It was one of the first locations exploited by snake divers like Ramon. In 1974 alone almost one half million snakes were taken. But our three-day experience at Gato was disappointing. During the twelve dives that Lenora and I made there, we saw only one sea snake. Obviously something had changed. We asked a local dynamite fisherman what had happened to all the snakes. He shrugged and said, "They don't come here anymore."

   Diving at Gato Island was a sad and uncomfortable experience. Sad because the great migrations of sea snakes to this island were a thing of the past. Uncomfortable because each dive was punctuated by the sharp concussion of dynamite exploding on distant reefs - a sound that seemed to herald the future for a marine wilderness that is perhaps closer to paradise than any other I have encountered.

   At present, no species of sea snake is considered endangered. But very little is known about the population dynamics of even the most common species. And many experts have difficulty telling one species from another in the field. So it is impossible to say what effect the recently developed markets for sea snake skin has had on the various varieties. Certainly there remain some places in the Philippines like Cervera Shoals that have only recently been discovered by snake divers and dynamite fishermen, and no doubt there are places yet untouched. Places where the long colorful bodies of sea snakes can be seen plying through the soft corals and entwined with one another in courtship. I would like to go back to Cervera Shoals one day, but I know that Ramon, Edwardo and others dive Cervera Shoals routinely and will continue to go there as long as they can receive two cents for a skin. Like Gato Island, Cervera Shoal may never be the same.