Moray eels (family Muraenidae) are a diverse group of over 200 marine eel species. Characterized by their elongated, snake-like bodies, they primarily inhabit warm, shallow saltwater environments, particularly coral reefs. While most species are marine, some can be found in brackish or even freshwater.
Distinctive Features
Moray eels possess a unique physical form. Their long, muscular, and laterally compressed bodies allow them to navigate narrow crevices. Unlike many other fish, moray eels lack pectoral and pelvic fins, contributing to their serpentine appearance. Their thick, smooth, scaleless skin is covered in a protective mucus layer, which can sometimes contain toxins. The green moray eel, for example, appears green due to a yellowish mucus coating its brown skin, which also protects it from parasites.
Their coloration and patterns are highly varied, ranging from solid colors to intricate mottled or spotted markings that provide camouflage. Morays have wide mouths with a protruding snout and powerful jaws. They possess sharp, often backward-pointing teeth designed for gripping prey. Some species, like the snowflake moray, have blunt, molar-like teeth adapted for crushing hard-shelled prey such as crustaceans.
A notable feature is their second set of jaws, known as pharyngeal jaws, located deep within their throats. These jaws shoot forward to grasp and pull prey into the esophagus after the primary jaws capture it. This mechanism compensates for their narrow heads, which prevent suction feeding. The constant opening and closing of a moray’s mouth, often perceived as an aggressive gesture, is simply how they breathe, pumping water over their small, rounded gill openings.
Habitat and Behavior
Moray eels primarily inhabit tropical and subtropical oceans, thriving in environments like coral reefs, rocky crevices, and sandy or muddy bottoms. They typically reside in hidden shelters, such as holes or caves, during the day. This secretive nature is part of their ambush predatory strategy, allowing them to wait for unsuspecting prey.
Most moray species are nocturnal hunters, becoming active during the night to search for food. Their eyes are relatively small, and they rely heavily on their highly developed sense of smell to locate prey in the dark underwater environment. As opportunistic carnivores, their diet typically includes smaller fish, crustaceans like crabs and shrimp, and cephalopods such as octopuses and squid. Some species, like the snowflake moray and zebra moray, primarily feed on hard-shelled invertebrates, utilizing their specialized teeth for crushing.
Morays employ various hunting techniques, often ambushing prey from their hidden lairs. They may also use their elongated bodies to pursue prey into tight spaces within the reef. In a fascinating display of interspecies cooperation, groupers have been observed signaling to moray eels to initiate joint hunts. Groupers, which hunt in open water, will shake their heads rapidly in front of a moray’s hiding spot to prompt the eel to flush out prey from crevices, benefiting both predators.
Morays and Human Interaction
Despite their formidable appearance and sharp teeth, moray eels are generally reclusive and not inherently aggressive towards humans. They tend to avoid confrontation, preferring to retreat into their hiding spots if disturbed. Bites usually occur when a moray feels threatened, provoked, or mistakes a hand for food, such as during hand-feeding activities.
Moray eel bites can be painful due to their sharp, backward-pointing teeth, designed to hold onto prey. These bites can cause significant bleeding and may lead to infection. Moray eels are not venomous; their bites do not inject toxins. Divers are advised to exercise caution in areas where morays inhabit, particularly avoiding placing hands into rocky crevices or disturbing the eels in their natural habitats.
Moray eels play a role in marine ecosystems as apex predators, helping to regulate populations of fish and invertebrates. Their presence contributes to the balance of coral reef communities. While their appearance might seem intimidating, understanding their behavior reveals them to be an integral part of the ocean’s biodiversity, typically posing little threat unless provoked.