The Sea Snake

(Hydrophiinae)

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The most frequently encountered type, the Laticauda colubrina, colored black and white stripes is the reflection of blue - purple if exposed to sunlight reflection.








Sea Snakes are a group of venomous snakes that inhabit the marine life, only coming to surface when needing to breathe and occasionally to lay eggs. Most live a fully equatic animal and are unable to live on land, unlike land snakes. They are mainly found in warm coastal waters from the Indian Ocean to the Pacific Ocean. There are approximately 70 (seventy) known species of sea snakes found in our oceans. Their bodie styles, habitat, reproduction manners, and all other important details bring together why a sea snake is the way that it is.






Description


The majority of adult sea snakes grow to anywhere between 3.9- 4.9 feet with largest reaching 9.8 feet. Their eyes are relatively small with a round pupil and most have nostrils that are located dorsally on each side of their face. They are completely equatic and have adapted to their enviornment in many ways, the most characteristic of which is a paddle-like tail that has increased their swimming ability. Their lack of ventrical scales means that they have become virtually helpless on land, but as they live out their entire life cycle at sea, they have no need to leave the water. Sea snakes do not have gills and must surface regularly to breathe (they are among the most completely aquatic of all air breathing vertebrates). In order to breathe, the sea snake must surface and the nostrils have valves consisting of a specialized spongy tissue to exclude water, and the windpipe can be drawn up to where the short nassal passage opens into the roof of the mouth. The lung has become very large and extends almost the entire length of the body, it is also possible that the extended lung serves to store air for dives (the sea snake can last underwater for an hour). They have extremely tiny fangs that are only 2-4 milimeters in length. A fold in the gums of sea snakes hides the fangs, and the fangs quickly emerge when biting. Sea snake fangs are fragile and may break off and remain in the wounds of their victims. To counter the problem of having weak fangs, the sea snake has potent venom that can easily paralyze, kill and begin the digestive process of the fish they target.
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Take a look at those fangs!

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Yellow-bellied sea snake, Pelamis platurus

Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Subphylum:
Vertebrata
Class:
Reptilia
Order:
Squamata
Suborder:
Serpentes
Family:
Elapidae
F. Boie, 1827
Subfamily:
Hydrophiinae


Habitat


Sea snakes live in warm tropical waters of the Indian Ocean and the Western Pacific Ocean. Most sea snakes prefer shallow waters near land, around islands, and especially waters that are somewhat sheltered. They have been known to swim up rivers and have been reported as far as 160 km (99 miles) from the sea.

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Dark Red= Indian Ocean, Red= Western (The habitats of Sea Snakes

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A sea snake swimming near a shallow surface.




Reproduction


There are two methods of reproduction that occur in different species of sea snakes:
  • One is that the sea snake may mate and lay their eggs on shore in crevices or caves, These eggs are capable of existing for long periods of time out of the water and will eventually find their way into the water where they will now stay for the rest of their life.
  • The second is that the sea snake may mate at sea and give birth to live young. In this case, the young is nourished by means of a placenta rather than an egg.

Sea Snakes seem to delay reproduction until they have enough stored energy to produce enough eggs or babies to completely fill up the space available in their body cavities. Since sea snakes are relatively small, they tend to produce only 2-4 babies and reproduction occurs about every 8-10 years in many species. After the babies are born, there is no parental care of the young, the snakes must be able to surface to breathe on their own.
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Mother sea snake that has mated at sea and the babies are feeding off her placenta and will soon be on their own.




Feeding

Most sea snakes prey on fish, especially eels. Once the prey is bitten, it stiffens and dies within seconds. Sea snakes are seperated into two sub-divisions according to feeding behaviors:
  • Bottom Feeders- these are the sea snakes that dive to deep depths of approximately 100 meters to locate their prey which includes eels and fish and also to raid burrows for fish eggs.
  • Pelagic Feeders- these are the sea snakes that are surface feeders and drift with the warm tides eating the fish that are below.
Sea snakes are relatively slow swimmers, so they rely more on of their stealth to capture their prey, Sea snakes corner their victims in small crevices of rocks. They strike with sharp fangs and inject their lethal venom into the victim, causing instant paralysis. They then swallow their prey whole thanks to their specially designed teeth and jaws. Some sea snakes are known for actually biting and eating bait at the end of a fish line which is discussed in more detail under the heading "Being Bit".
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Bottom Feeder searching for trying to locate prey at the bottom of the ocean.





Shedding of Skin

All snakes shed their skins and sea snakes shed every two to six weeks, which is more frequently than land snakes and more often than needed for growth alone. The process involves rubbing the lips against coral or other hard substrate to loosen the ski. The snake then catched the skin against something to anchor it and crawls forward leaving the skin turned inside out behind it. Skin shedding allows sea snakes to rid themselves of fouling marine organsims such as algae, barnacles, and byrozoans. Otherwise they would be covered with fouling organisms and this would interfere with the snakes ability to swim efficiently and may also cause disease.


Being Bit

Sea snakes are very shy and not aggressive by nature unless provoked. It is common for fisherman to be bit when they are trying to get the snake out of their net after it has caught on to the bait. As previously noted, sea snake fangs are very fragile and may break off and remain in the wounds of their victims. To counter the problem of having weak fangs, sea snakes have potent venom that can easily paralyze, kill and begin the digestive process of the fish they target. An adult sea snake may carry enough venom to kill approximately three adult people. Its primary neurotoxin can cause peripheral paralysis. The sea snake venom is approximately two times more potent than the land snake venom. Symptoms are often delayed but may occur in minutes or up to 8 (eight) hours after a sea snake bite. The poisoned person may experience nausea, vomiting, thick tongue, difficulty speaking and swallowing, blurred vision, weakness, numbness or stiffness. More severe reactions include paralysis, drooping eyelids, dark brown urine, lockjaw, difficulty breathing, and blue lips and tongue. Death may occur but only in rare cases of fisherman has it been documented.
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Sea snake ready to attack and bite a diver that posed a potential threat.


Works Cited