Drifting with the rising tide (6), the north-western mangrove sea snake can be seen foraging among goby burrows and crab holes (1) (6), and is known to search for its prey out of the water on salt flats during low tide (1). This fish-eating species feeds mostly on gobies (1) (6) (10) and their eggs (1), and like other snakes it swallows its prey whole (10). It has been suggested that the north-western mangrove sea snake may have an extremely specialist diet, and may not eat any fish species other than gobies (11). Although a venomous species (4) (5), the north-western mangrove sea snake does not produce venom as toxic as that of many other sea snakes (5).
Despite being an air-breathing animal, the north-western mangrove sea snake is capable of remaining underwater for up to two hours at a time, before surfacing to breathe again. Its single, elongated lung, which extends for almost the entire length of its body, is highly efficient for gas exchange, and sea snakes are also able to absorb oxygen through their skin when underwater. As in other sea snake species, the north-western mangrove sea snake has specialised valves which block off the nostrils while underwater (6).
Living in the marine environment poses several other challenges, and like other sea snake species, the north-western mangrove sea snake has a specialised gland under its tongue which enables it to excrete excess salt from its body. A sea snake sheds its skin approximately once every two to six weeks, by rubbing its lips against something hard such as coral until the loosened skin is anchored there. The sea snake then crawls forwards, leaving the skin turned inside out behind it. By shedding its skin so frequently, a sea snake can get rid of the many marine species, such as algae and barnacles, which become attached to it (6).
Like most species of sea snake, the north-western mangrove sea snake is viviparous, meaning that it gives birth to live young rather than laying eggs. Mating in sea snakes is a lengthy affair, and the males are unable to disengage from the female until copulation is complete. There is no information available on the breeding season of the north-western mangrove sea snake or the number of young produced by this species (6).