Annulated Sea Snake

The annulated sea snake, or blue-banded sea snake, is a venomous sea snake of the Indian Ocean and western Pacific, recorded from the Persian Gulf and Iran through Pakistan, India and Sri Lanka to Southeast Asia. It is greenish-olive above with blackish or olive transverse bars broadest on the back, sometimes joined by a black band along the belly, or yellowish with a black vertebral band and a few bars on the neck. One quoted description gives a head and body length of 1,360 mm and a tail of 140 mm (Wikipedia, general species account).

A 2019 study found that it uses a complex network of blood vessels in the head, the Modified Cephalic Vascular Network, which helps supply the brain with extra oxygen from the water when submerged. Nationally Least Concern (Sri Lanka National Red List 2012).