Slender-necked Seasnake  |  

Hydrophis coggeri


The Slender-necked Seasnake is slightly built with a small head, slender anterior and a moderately deep and laterally compressed posterior region. The colouring of juveniles is more pronounced than that of adults. In juveniles, the head is black with conspicuous yellow markings on the nasal and postocular regions. The body is pale yellowish in juveniles but changes to olive-grey in adults. The distal and ventral portions of the tail are black. The body and tail have 30–40 blackish cross bands which are widest on the dorsal and ventral surfaces. The head scales are enlarged and regular. The body scales are imbricate (overlapping) and form 29–34 rows at the mid-body. The ventral scales are usually undivided; about as wide as, or slightly wider than, neighbouring scales; in numbers of 280–360. The Slender-necked Seasnake grows to about one metre.

Government evidence of impact of climate change:

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  • IUCN Red List Assessment, Hydrophis coggeri

    Climate change may thus threaten all sea snakes which are coral reef specialists (Francis 2006).