Meet Hydrophis cyanocinctus, a snake that can breathe through the top of its own head. The three meter (9.8ft) species, which is native to Australian and Asian coastal waters, ...

The re-elaboration of Hydrophis cyanocinctus' visual function was in response to its bright underwater environment—which differed from the low-light habitats of some of its ancestors.

Hydrophis cyanocinctus is the only sea snake species known to breathe through the top of its head, using a special arrangement of blood vessels in much the same way as fish gills.

The re-elaboration of Hydrophis cyanocinctus’ visual function was in response to its bright underwater environment – which differed from the low-light habitats of some of its ancestors.

During submersion, the blue-banded sea snake (Hydrophis cyanocinctus) is now thought to use an extensive vascular network across the top of its head to absorb oxygen from the surrounding water.

One of these is the venomous, blue-banded sea snake (Hydrophis cyanocinctus), ... they found that H. cyanocinctus snakes have evolved to bring back four copies of this ancestral SWS1 gene.