White Eyed Moray Eel

Moray eels are one of those animals that look considerably more threatening than they are. The constant opening and closing of the mouth, the fixed unblinking stare, the habit of lurking in dark crevices — everything about their appearance suggests danger. In reality the white eyed moray is a reef scavenger and opportunistic hunter that has very little interest in divers, as long as divers have very little interest in reaching into the holes where it lives.

The white eyed moray gets its name from the pale, almost luminous eyes that give it a particularly alert expression. It’s a medium-sized species — most individuals around Koh Tao run between 60 and 100 centimetres — with the characteristic mottled brown and cream patterning common to many Indo-Pacific moray species. You’ll find them on virtually every reef dive on the island, usually with just their head visible at the entrance of a crevice or beneath a coral ledge.

What most people don’t know about moray eels is that they have two sets of jaws. The outer oral jaws handle the initial bite, but inside the throat is a second set of pharyngeal jaws that shoot forward independently to grip prey and pull it deeper into the digestive tract. It’s an extraordinarily effective feeding mechanism and one of the more unusual adaptations in reef biology.

The opening and closing of the mouth is breathing, not aggression. Moray eels lack the gill covers most fish use to pump water over their gills, so they move water by opening and closing their mouths instead. A moray eel sitting calmly in its crevice with its mouth cycling steadily is simply going about its business. One that has flattened its body, raised its head, and is oriented toward you is telling you to back off — a message worth listening to.