Hawaii has one sea snake, the yellow-bellied sea snake (Pelamis platurus.) As the common name suggests, this species has a vivid yellow underside, which contrasts with a dark blue-gray, brown or gray back. If you look down and see a blue or blue-ish snake swimming in Hawaiian waters, it can only be this species.
Aside from the handsome coloration, yellow-bellied sea snakes lack distinction in their appearance. They remain fairly small, with the females, the larger of the sexes, growing to a maximum of little more than 3 feet in length, while the males are considerably smaller. They have slim, somewhat flattened bodies and relatively small fangs. Rather than laying eggs, the females give birth to small litters of live young in the sea, and so have no reason to return to land. Juveniles and adults subsist on a diet of small fish, which they lie in wait for near the surface.
The yellow-bellied sea snake’s range stretches through the Indian and Pacific oceans from the western coast of the Americas to the east side of Africa. They reside mostly in tropical areas, although individuals are occasionally spotted in cooler waters, probably swept there by ocean currents. Their range includes the waters around Hawaii. They tend to be shy and elusive, favoring open water. This means that even the most alert swimmer, snorkeler or scuba diver might struggle to catch a glimpse.
Relationship with Humans
Yellow-bellied sea snakes happen to be venomous yet don’t actually pose much of a threat to swimmers. Given the option, a yellow-bellied sea snake would much rather flee than fight. It’s sensible to avoid getting too close, though, so if you happen to come across one while swimming or snorkeling, move away. Under no circumstances chase or corner the animal. Humans haven’t been a serious threat to the snakes either. Although many aquatic animals are in grave danger from human activity, the yellow-bellied sea snake is not one of them, remaining plentiful and widespread. The International Union for the Conservation of Nature notes that low-level threats exist, mostly from pollution and fishing activities, but don’t seem to be causing major problems to the species.
If you’re in Hawaii and meeting a sea snake sits high on the “to do” list, be prepared for disappointment -- this is not an easy creature to find. Unlike some whales, dolphins and fish, sea snakes do not jump out of the water in elaborate displays. They also aren’t likely to approach people and tend to move away when there’s a lot of traffic in the water. You might be slightly more likely to see one from a boat, as you can explore a larger area, and yellow-bellied sea snakes don’t dive deep. Fisherman’s sunglasses help you see below the surface of the water, useful when wildlife spotting on deck.
Judith Willson has been writing since 2009, specializing in environmental and scientific topics. She has written content for school websites and worked for a Glasgow newspaper. Willson has a Master of Arts in English from the University of Aberdeen, Scotland.