Interesting discovery of sea snakes

Although living in oceans, sea snakes do not drink saltwater even if they are very thirsty.

Sea snake.Photo: divegallery

Until now, many scientists believed that the ancestors of sea snakes used to live on land before conquering the ocean. To adapt to the new environment, their bodies create a special hydrological mechanism whereby the salt gland within the sea snake's body filters and removes salt in seawater.

But some scientists from Florida University (USA) discovered that 3 species of sea snakes near Taiwan island only drink soft drinks or dilute salt water (with 10-20% salt). In tests, sea snakes refused to drink natural seawater despite being thirsty.

Sea snakes are members of the Elapidae family of venomous snakes, including the tiger, mamba and coral snakes (alternating red, yellow and black colors along the body). Although most of the Elapidae family live in saltwater environments, they occur in areas with heavy rainfall. This led scientists at the University of Florida to hypothesize that sea snakes need fresh water.

To test the hypothesis, the team monitored several sea snakes in the laboratory. They did not allow them to be exposed to seawater for two weeks. During that time their body mass decreased significantly. After solid weighing, experts drop them into saltwater tank for 20 hours. They picked them up and put them on the scale. The results showed that the body weight of the snake did not increase. This means that they will not drink salt water even though they are very thirsty.

When the test was repeated with fresh water, the majority of the snake flooded immediately. Subsequent tests show that sea snakes can also survive in dilute salt water environments.

Some species of sea snakes are distributed in closed water areas (surrounded by islands or other natural obstacles) although there is no fresh water supply. According to Harvey Lillywhite, the leader of the research team, they are likely to live on rainwater. Quiet water in closed water (such as bays, lagoons) helps fresh water rise above salt water before they blend together. That explains why sea snakes often appear in densely dense lagoons than open oceans in the ocean.

Scientists have assumed that sea snakes' salt glands help filter salt out of the water, but Harvey thinks that the salt glands help sea snakes balance ions by removing excess salt from the blood.