Moray eels are frequently mistaken for sea snakes or monsters due to their serpentine appearance. Despite their lack of traditional fish-like features, moray eels are definitively fish. Their elongated bodies and unique features are adaptations perfectly suited to their hidden, crevice-dwelling lifestyle.
The Scientific Classification
Moray eels belong to the Order Anguilliformes, which encompasses all true eels, confirming their place within the class of bony fishes (Osteichthyes or Actinopterygii). Like all fish, they possess a vertebral column and use gills to extract oxygen from the water. This internal anatomy distinguishes them from reptiles like sea snakes.
Their classification within the family Muraenidae includes approximately 200 species found worldwide in tropical and temperate marine environments. Although they share a common lineage with other bony fish, their lineage diverged long ago, resulting in the unique form we observe today. This divergence allowed them to develop features suited for navigating tight spaces.
Unique Physical Adaptations
The serpentine body shape is a successful adaptation for a life spent in rocky reefs and coral crevices. Unlike most bony fish, moray eels lack protective, overlapping scales, instead having thick, smooth skin covered in mucus. For example, the green moray eel is actually brown, but a yellow-tinted mucus layer makes it appear green for camouflage.
Their fins are dramatically reduced; they completely lack pectoral and pelvic fins, relying on a long, continuous dorsal and anal fin that runs along the length of the body. Their breathing method, known as buccal pumping, requires them to constantly open and close their mouths. Since morays lack the bony gill covers (operculum) of most fish, they must force water over their internal gills.
Pharyngeal Jaws
Perhaps their most unique predatory adaptation is the pharyngeal jaw, a second set of jaws located in their throat. When a moray grasps prey, the pharyngeal jaws shoot forward, latch onto the prey, and then retract, effectively pulling the meal down the eel’s esophagus. This feeding mechanism compensates for their inability to use suction-feeding effectively in their narrow burrows, allowing them to consume surprisingly large prey.
Habitat and Hunting Behavior
Moray eels are solitary, bottom-dwelling predators found in tropical and subtropical regions, inhabiting coral reefs, rocky shorelines, and mangrove areas. They spend daylight hours hidden in burrows, often with only their heads protruding from the rock or crevice. This reclusive habit aligns with their identity as nocturnal hunters.
As ambush predators, morays do not chase down prey in open water but instead wait to strike at fish, crabs, and octopuses that pass by their hiding spots. Their eyesight is relatively poor, so they rely on a highly developed sense of smell to locate food. Specialized nostrils on the snout allow them to detect chemical cues in the water, guiding them to their next meal in the dark.