Wolf Eel

Fascinating facts about the Wolf Eel

• In 1855, physician-ichthyologist William Orville Ayres gave this fish its first formal description from a specimen caught in San Francisco Bay, making it the sole member of the genus Anarrhichthys that he also created that year.
• At full size this marine predator can stretch up to 2.4 m (7 ft 10 in) long and weigh as much as 18.4 kg (41 lb), yet it still fits inside the narrow crevices and caves it calls home.
• When a pair reaches about seven years old, the female can lay up to 10,000 eggs in a single clutch, shaping them into a grapefruit-sized sphere that the devoted male helps guard until hatching after 91–112 days.
• Its jaws sport front-row canine teeth and back molars, allowing it to crush hard-shelled prey like sea urchins and mussels, though in captivity it will choose soft squid over hard shells to avoid wearing down its back teeth.
• Even after its head is severed, this fish can still deliver a painful bite, a reminder that its powerful jaws remain functional long after the rest of the body is gone.

At a glance

About the Wolf Eel

The wolf eel (Anarrhichthys ocellatus) is a strikingly robust fish that defies its common name. Growing up to 2.4 m (7 ft 10 in) and 18.4 kg (41 lb), it bears a head reminiscent of the true wolffishes, complete with powerful canine front teeth and molar-like posterior teeth that can crush the shells of crabs, sea urchins, mussels and clams. Young individuals flash an orange hue dotted with dark posterior spots, while adults shift to muted greys, brown-grey or dark olive tones. Their single dorsal fin stretches the length of the body, supported by 228–250 flexible fishbones, and they lack pelvic fins, a lateral line, and pelvic rays, setting them apart from true eels. In the cold, rocky reefs and sea-cave labyrinths of the North Pacific, from the Sea of Japan and the Bering Sea down to Northern California, as deep as 226 m (741 ft), they carve out permanent homes, often pairing for life in a single cavern. These monogamous partners engage in a meticulous breeding ritual from October through winter, beginning at about seven years of age. The female extrudes up to 10,000 eggs, which the male fertilizes; together they coil around the gelatinous sphere, guarding it while alternately feeding. The eggs hatch after 91–112 days, during which the female circulates water and massages the clutch to ensure oxygenation. Curious yet rarely aggressive, large wolf eels can deliver a painful bite, even after decapitation.

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