Harlequin Snake Eel

• Its ringed livery mimics that of the highly venomous banded sea krait, which protects it from predators that avoid the snake: a case of Batesian mimicry.
• It buries itself tail first, backing into the sand with the hardened tip of its tail rather than digging with its head.
• Unlike the moray eels, with which it is confused, it has no tail fin.
• It mimics a venomous sea snake. Its black and white bands and its way of swimming copy the yellow-lipped sea krait, Laticauda colubrina, which is extremely venomous. The eel itself is completely harmless: it is a case of Batesian mimicry.
• The deception works even at close quarters. Researchers who have watched the two animals in the same area describe how hard it is to tell them apart at any distance.
• The mimicry changes its life: where it lives alongside the snake it feeds openly by day, whereas in areas where the snake is absent it becomes nocturnal.
• Its snout and tail are hard and pointed for digging in the sand. Hence a well-documented macabre story: mummified specimens have been found inside the body cavity of large fish, having been swallowed whole and having pierced the predator's stomach from within.
• It has between 190 and 202 vertebrae.
• In 2021 it was recorded for the first time in Hawaiian waters, extending its known range.

Skeleton type

Vertebrate - internal bony skeleton (fish)

Habitat & environment

Sandy and coral-rubble bottoms of the Indo-Pacific, from 0 to 30 m

Sources consulted: FishBase (Froese & Pauly, eds.); Lista Roja de la UICN; Heemstra; Reef Life Survey