Banded Sea Krait

The head of a yellow-lipped sea krait is black, with lateral nostrils and an undivided rostral scale. The upper lip and snout are characteristically colored yellow, and the yellow color extends backward on each side of the head above the eye to the temporal scales.

The yellow-lipped sea krait is widespread throughout the eastern Indian Ocean and Western Pacific. It can be found from the eastern coast of India, along the coast of the Bay of Bengal in Bangladesh, Myanmar, and other parts of Southeast Asia, to the Malay Archipelago and to some parts of southern China, Taiwan, and the Ryukyu Islands of Japan. The species is also common near Fiji and other Pacific islands within its range. Vagrant individuals have been recorded in Australia, New Caledonia, and New Zealand. Six specimens have been found around the North Island of New Zealand between 1880 and 2005, suspected to have come from populations based in Fiji and Tonga. It is the most common sea krait identified in New Zealand, and second-most seen sea snake after the yellow-bellied sea snake - common enough to be considered a native species, protected under the Wildlife Act 1953.

Hunting is often performed alone, but L. colubrina kraits may also do so in large numbers in the company of hunting parties of giant trevally and goatfish. This cooperative hunting technique is similar to that of the moray eel, with the yellow-lipped sea kraits flushing out prey from narrow crevices and holes, and the trevally and goatfish feeding on fleeing prey.

While probing crevices with their heads, yellow-lipped sea kraits are unable to observe approaching predators and can be vulnerable. The snakes can deter predators, such as larger fish, sharks, and birds, by fooling them into thinking that their tail is their head, because the color and movement of the tail is similar to that of the snake's head. For example, the lateral aspect of the tail corresponds to the dorsal view of the head.

Yellow-lipped sea kraits are semiaquatic. Juveniles stay in water and on adjacent coasts, but adults are able to move further inland and spend half their time on land and half in the ocean. Adult males are more terrestrially active during mating and hunt in shallower water, requiring more terrestrial locomotive ability. Adult females, though, are less active on land during mating and hunt in deeper water, requiring more aquatic locomotive ability. Because males are smaller, they crawl and swim faster than females.

The yellow-lipped sea krait is oviparous, meaning it lays eggs that develop outside of the body.

Each year during the warmer months of September through December, males gather on land and in the water around gently sloping areas at high tide. Males prefer to mate with larger females because they produce larger and more offspring.

When a male detects a female, he chases the female and begins courtship. Females are larger and slower than males, and many males escort and intertwine around a single female. The males then align their bodies with the female and rhythmically contract; the resulting mass of snakes can remain nearly motionless for several days. After courtship, the snakes copulate for about an average of two hours.

Because yellow-lipped sea kraits spend much of their time on land, they are often encountered by humans. They are frequently found in the water intake and exhaust pipes of boats. They are also attracted to light and can be distracted by artificial sources of light, including hotels and other buildings, on coasts.

Fewer bites from this species are recorded compared to other venomous species such as cobras and vipers, as it is less aggressive and tends to avoid humans. If they do bite, it is usually in self-defense when accidentally grabbed. Most sea snake bites occur when fishermen attempt to untangle the snakes from their fishing nets.