The yellow-lipped sea krait (Laticauda colubrina), also known as the banded sea krait or colubrine sea krait, is a species of venomous sea snake found in tropical Indo-Pacific oceanic waters. The snake has distinctive black stripes and a yellow snout, with a paddle-like tail for use in swimming. It spends much of its time under water to hunt, but returns to land to digest, rest, and reproduce. It has very potent neurotoxic venom, which it uses to prey on eels and small fish. Because of its affinity to land, the yellow-lipped sea krait often encounters humans, but the snake is not aggressive and only attacks when feeling threatened. 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. serpente di mare bocca gialla

Yellow-lipped sea Krait – Serpente di mare bocca gialla – Laticauda colubrina – www.intotheblue.it
The body of the snake is subcylindrical, and is taller than it is wide. Its upper surface is typically a shade of blueish gray, while the belly is yellowish, with wide ventral scales that stretch from a third to more than half of the width of the body. Black rings of about uniform width are present throughout the length of the snake, but the rings narrow or are interrupted at the belly. The midbody is covered with 21 to 25 longitudinal rows of imbricated (overlapping) dorsal scales. The dorsal and lateral scales can be used to differentiate between this species and the similar yellow-lipped New Caledonian sea krait, which typically has fewer rows of scales and scales that narrow or fail to meet (versus the yellow-lipped sea krait’s ventrally meeting dark bands). The tail of the snake is paddle-shaped and adapted to swimming.

Yellow-lipped sea Krait – Serpente di mare bocca gialla – Laticauda colubrina – www.intotheblue.it
The yellow-lipped sea krait is widespread throughout the eastern Indian Ocean and Western Pacific. 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.

Yellow-lipped sea Krait – Serpente di mare bocca gialla – Laticauda colubrina – www.intotheblue.it
Body adaptations, especially a paddle-like tail, help yellow-lipped sea kraits to swim. These adaptations are also found in more distantly related sea snakes (Hydrophiinae) because of convergent evolution, but because of the differences in motion between crawling and swimming, these same adaptations impede the snake’s terrestrial motion. On dry land, a yellow-lipped sea krait can still move, but typically at only slightly more than a fifth of its swimming speed. In contrast, most sea snakes other than Laticauda spp. are virtually stranded on dry land. Their main predators are eagle rays and sharks.
(extract from Wikipedia)