Sea snake is a poisonous snake that lives in the sea. The nostrils of sea snakes are upward and have valves that can be opened and closed. After inhaling air, it can close its nostrils and dive into the water 10 minutes. The body surface is covered with scales, and under the scales is thick skin, which can prevent seawater infiltration and body fluid loss. The salt glands under the tongue have the function of expelling excess salt that enters the body with food.

There are 19 species of sea snakes in China, which are distributed in the coastal areas of Guangdong, Guangxi, Fujian, Taiwan Province, Zhejiang, Shandong, Liaoning and other provinces.

Common ones are blue-ringed sea snake, flat-headed sea snake and long-nosed sea snake. Sea snakes can be used as medicine, and have the effects of expelling wind and relieving pain, promoting blood circulation and dredging collaterals, nourishing and strengthening the body.

It has no pain when it bites, and its toxic attack has an incubation period. After being bitten by a sea snake, there is no obvious poisoning symptom within 30 minutes or even 3 hours. However, this is very dangerous and easy to make people numb. People who are bitten may die within hours to days. Serpentidae and Cobra belong to the family Agkistrodon. A poisonous snake with short front teeth. All the sea snakes found are highly toxic. Sea snake venom is a colorless or yellowish viscous liquid, similar in nature to land snake venom, but far more toxic than general land snake venom, belonging to the strongest animal venom. Some species are more than ten times as toxic as rattlesnakes, while the venom of sea snakes is twice as toxic as cobra venom and 80 times as toxic as sodium cyanide. The toxicity of sea snakes is neurotoxic, and there is no serum detoxification.

The most poisonous sea snake in the world is the Belcher Sea Snake, which lives around the rocks in the ashmore Islands in northwest Australia. According to the toxicity per unit volume, its toxicity is 200 times that of king cobra.