sea snakesSea snakes did not make the cut for Wild Reef. The strikingly striped blue-lipped sea kraits—all bold bands of turquoise and black—would have required a fairly large habitat all to themselves among the realistically teeming multispecies displays.

And, of course, these elapids—hissing cousins of cobras, taipans and terrestrial kraits—are among the most venomous snakes in the world.

“As divers go into most of the exhibits in Wild Reef,” says aquarium collections director George Parsons, “safety was another reason to look into other options.”

But Shedd did have sea snakes briefly in the early 1980s—although not by design. U.S. Fish and Wildlife Service agents at O’Hare discovered illegally exported yellow-bellied sea snakes in shipments to an aquatic animal wholesaler and confiscated them. Next stop: Shedd. For years we’ve assisted FWS, serving as a repository for illegally imported and seized aquatic animals, including baby sea turtles and live corals, and we’ve developed classes specifically for wildlife agents to help them identify a wildly diverse array of marine fishes and invertebrates. The young, foot-long sea snakes were in pretty rough shape from shipping and didn’t respond to ministrations of live foods and carefully adjusted environmental conditions. But while they were here, they fascinated the aquarists as well as our colleagues at the Field Museum.

Sea snakes are the most abundant and widely distributed group of venomous reptiles in the world. About 60 species are found throughout warm coastal waters of the Indian and Pacific Oceans. A sea snake’s muscular body is compressed so that it looks more like an eel than a snake, and it has a flattened, paddlelike tail that gives it added propulsion through the water. Most species spend their entire lives at sea; the kraits we chose not to acquire are among the few species that can move on land.

Like all reptiles, however, sea snakes are air breathers. They have valves in their nostrils to shut out water until they surface to breathe. Most of them can also respire through their skin—an unusual adaptation among scaly-skinned reptiles—which allows them to stay submerged for long periods and even dive. Most also are live-bearers. The mother retains saclike eggs in her body, and at birth, the young swim away, small versions of an adult.

Although sea snakes have some of the most potent venoms of all snakes—a chemical cocktail of fast-acting neurotoxins and myotoxins that act on the nervous system and muscles—they generally don’t envenomate anything but their prey. Sea snakes have been described as nonaggressive, mild-tempered, docile and even “sunny” in disposition (perhaps the result of having few or no predators). Local fishermen are the most likely to encounter them, caught in their nets, and they toss them back in the water. Bites are rare and then usually “dry”—the snake withholds its venom—although that can vary by species.

Back in the ’80s, Shedd’s aquarists didn’t take any chances. The snakes’ habitat was fitted with a cedar-framed, stainless-steel-meshed, padlocked cover. The aquarists had to work in pairs when they opened the habitat to care for the snakes, and both people had to wear welders gloves, which the snakes’ small fangs couldn’t penetrate.

Eventually, the supplier in the Philippines got word that his importer was facing big fines if any more snakes showed up in the shipments, and the stream of sea snakes stopped.

While Shedd no longer has sea snakes, there are plenty of other venomous animals to visit! Check in next week for another "Name Your Poison" post or read one of our previous posts:
Where’s Nematocyst?
How Venomous Is It?

Posted by Karen Furnweger, web editor