Sea snakes are some of the most unusual creatures in the sea. Highly venomous, versatile, air-breathing reptiles, they require occasional trips to the surface in order to get their necessary intake of air. However, their biology has evolved differently when compared to any other reptile, and they were even discovered to be capable of breathing through their skin. Young sea snakes have to be independent as soon as they are born. Being born underwater, they are already able to instinctively travel to the surface for their vital supply of oxygen.
The sea snake’s unique body and respiratory system allows it to dive to extensive depths and stay there for quite some time before resurfacing to breathe. Sea snakes have evolved to live underwater, and some species aren’t even able to survive on land. They can spend 30 minutes up to about 2 hours between dives, only surfacing for a short time to take a breath on occasion. Their highly efficient metabolism also plays an important role in this, allowing them to recuperate quickly after a long dive and move underwater with ease, without the need for extensive oxygen expenditure.
Unlike most reptiles, sea snakes only have one long, cylindrical lung that stores all their oxygen. They have evolved from reptiles with two long, however, over millions of years, they have adapted to this breathing configuration, since it became most practical for their unique needs and their long, slim bodies. While the lung extends over most of the length of the sea snake’s body, only part of it has blood vessels and is used for breathing. The rest of the lung is essentially a well-calibrated device meant to allow the snake to control its buoyancy. Also, sea snakes’ respiratory system as a whole is quite unique. They have nostrils that are similar to a whale’s blowhole, and can close when they’re underwater, or open up to allow for easy breathing when they’re at the surface.
One of the more unusual traits associated with sea snakes is their ability to breathe through their skin. For most reptiles, this isn’t a normal trait, since reptile skin is usually scaly and tough. However, studies conducted with the help of the pelagic snake species, Pelamis Pleturus have revealed that about 20-30% of all the oxygen used by these sea snakes is procured through the skin. This value is surprisingly high, and scientists have found that even most fish only take about 7% to 20% of their oxygen through the skin, with only a few species breathing as much as 30% through their skin.