Sea Snake

     Sea snakes are venomous and live in marine environments for the majority if not all of their lives.  They are adapted to living in aquatic environments and are usually unable to move on land.  They are found in warm coastal waters of the oceans.  They have tails that are paddle-like and have compressed bodies that make them appear similar to eels.  They are unlike fish in that they do not have gills and have to come to the surface in order to breathe.  Some of these snakes are the most venomous of all snakes, including land-dwelling snakes.  Some of them may only bite when provoked, but others are very aggressive.

    Adult sea snakes of most species will grow between four and five feet in length.  The largest of these snakes grows to a maximum of about three meters.  The eyes of the sea snakes are small and they have a round pupil.  The majority have nostrils that are located dorsally on the snake.  They have short fangs and up to eighteen smaller teeth found behind the fangs. 

     Most of the sea snakes are totally aquatic and they have adapted to their environments in a number of ways.  The first adaptation is a tail that is paddle-like in order to increase their ability to swim.  The bodies are also frequently laterally compressed, which makes them look more like eels.  The ventral scales are often reduced in their size, and this causes them to be very helpless if they were to be on land, but since they live in the sea, this is unnecessary.  There is one species that has kept its enlarged ventral scales, and those are the sea kraits, which are more primitive and still spend some time on land. 

    The tongue of a sea snake tends to be shorter than the tongues of land snakes.  The forked tips only will protrude from the mouth of the snake.  The nostrils have valves that include a specialized spongy tissue that will keep the water out.  The lung of the sea snake is very big and will extend nearly the entire length of the body of the sea snake.  Most sea snakes have the ability to respire using their skin.  This is atypical, since the skin of reptiles is usually scaly and thick.  Experiments that have been conducted conclude that the species of black and yellow sea snakes only are able to achieve about 20% of their oxygen needs through respiration of the skin.  It is suggested that this method is necessary for deep dives. 

     Since sea snakes live in salt water, they will ingest a lot of salt.  This means that they must have a way of regulating the salt concentration in their blood.  The sea snakes have posterior sublingual glands which are under and around their tongue sheath which allow them to get rid of salt with the action of their tongues. 

     Snakes normally live in the warm tropical areas of the Indian Ocean and the western Pacific Ocean, and there are also a few species of sea snakes that live in Oceania.  Sea snakes do not live in the Atlantic Ocean.  Most snakes prefer to live in shallow waters that are fairly close to land and around islands.  They especially like to live in waters that are somewhat sheltered.  They can swim up rivers and they have been reported up to 160 km. from the sea.  Some sea snakes live in mangrove swamps and other brackish water habitats. 

     Most sea snakes are considered to be docile and reluctant to bite.  When they are taken out of water, however, their movements can become erratic.  They are not able to move well on land, so they crawl awkwardly.  They can also become aggressive and will strike wildly at things that move.  They are also caught by fishermen who usually throw them back barehand and often are unharmed.  When they are on land, sea snakes are unable to coil and strike like terrestrial snakes strike. 

     Sea snakes are often active during both day and night.  The snakes are sometimes seen basking in sunlight near the surface of the water.  If you disturb a seasnake, it will often dive deep into the ocean.  They have been known to dive over 295 feet into the ocean.  They can stay underwater for a few hours at a time. 

     Most sea snakes eat fish, particularly feeding on eels.  When they eat eels, they bite them, and then the eels stiffen and die quickly.  Some species of sea snakes eat crustaceans and mollusks, and some will even eat fish eggs. 

    Young sea snakes are born alive in the water.  They live there in the water for their entire life.  The young can be born very big in some species where they are reported to be half as long as their mothers at birth.  The genus Laticauda is the exception because it lays eggs on land.

     The majority of sea snakes are venomous.  The good news is that when a sea snake does bite, there is usually not much venom that is injected.  When the venom is injected, teeth may remain in the wound.  There isn't usually any swelling involved.  The lymph nodes are rarely affected.  If the case is serious, the most important symptoms include a rapid breakdown of skeletal muscle tissue as well as paralysis.  Some of the early symptoms may include a thick-feeling tongue, thirst, headache, sweating, and even vomiting.  The symptoms that may occur after thirty minutes to several hours after the bite may include aching, tenderness of muscles, and stiffness all over.  Stretching the muscles may also be painful.  Trismus, which is similar to tetanus, may be common.  This will be followed with symptoms that include flaccid paralysis, which begins with ptosis and the paralysis of the voluntary muscles.  Then a paralysis of the muscles that are necessary for respiration and swallowing may be fatal.  After three to eight hours, myoglobin resulting from muscle breakdown may begin to show up in blood plasma, and this can make the urine turn brown, black, or a dark reddish color.  This may eventually lead to acute renal failure.  Hyperkalemia, the result of muscle breakdown, can occur after 6-12 hours, and this can lead to cardiac arrest.