Anarrhichthys ocellatus, known as the wolf eel, is the only species in the Anarrhichthys genus. They have long, snakelike bodies and large, boxy heads. But the wolf eel is most famous for its powerful bite, that can crush through hard shells and, according to internet legend, full cans of coca cola. But beyond the ferocious bite, wolf eels are anatomically adapted for life among coral reefs, best spent with the eels they love.

1. Wolf Eels are actually wolffish, not true eels.

Wolf eels are not true eels. They are actually fish. Although wolf eels have long, snakelike bodies like eels, they also have scales, pectoral fins, and paired gill slits. Wolf eels belong to the Anarhichadidae, or wolffish, family. Also called sea wolves, this fish family gets its name from their long, sharp teeth. And like wolves, wolf eels are ferocious predators.

wolf eel
Image by GIPHY

2. Wolf Eels have 4-6 fang-like teeth in the front of their mouths and molars in the back

Wolf eels have powerful jaws well adapted to crushing hard shells. Wolf eels have between four and six canine fangs at the front of their mouths. These fangs are for snagging and biting prey. Then the eels have rows of strong molars in the back of their mouths to crush and grind down prey. Because of these strong jaws, the wolf eel’s skull is much larger than it’s long, thin body.

3. Wolf Eels have between 228-250 small fishbones that support the dorsal fin

The wolf eel has one long dorsal fin that runs from the top of its head and down to the end of its body. The eel also has 228-250 small fishbones that support the dorsal fin. Since wolf eels are vertebrates, they have a long spine extending from their skull to their tails. The fishbones are long and skinny bones that extend from the spine.  These bones are long, thin, and flexible. They provide the fin with support but also allow for quick movement.

Wolf Eel skeleton
Image by Kelly The Deluded

Wolf Eel skeletons are made of cartilage

Wolf eels have cartilaginous skeletons. This means that their skeletons are made of cartilage instead of just bone tissue. Cartilage is sturdy but flexible. It’s what allows the wolf eel to maneuver its long body so gracefully and squeeze into narrow cracks and crevices of its habitat. This also differentiates them from ancient bony fish, who had stiff skeletons made entirely of bone tissue.

4. Wolf eels can grow over 8ft long and weigh over 80 pounds.

The average wolf eel’s size is usually between 6-7ft long. However, it can grow even larger. Wolf eels can grow over 8ft tall. The largest wolf eel known to man was about 8.2ft tall. But it only weighed 44 pounds. Many wolf eels are as heavy as 88 pounds.

5. Wolf eels have small scales embedded into their skin

Wolf eels, as fish, actually have scales. However, the scales are small and embedded in the eel’s skin. The small, patterned scales give the eel a leathery, snake-like appearance. However, sometimes the scales on an eel’s back become itchy. Eels don’t have hands to scratch their backs, but they can swim upside down to scratch their backs along a rock.

wolf eel
Image by Chris Wilson

Wolf eels have a protective coat of slime that acts as their immune system

Wolf eels, like morays, are covered in an outer coating of slime. This slime helps them slip through narrow passages in reefs. It also acts as an immune system. The thick slime protects the eel from outside threats.

6. Wolf Eels are born bright orange, and their colors fade over time

Although adult wolf eels are usually dark grey, blue, or green, juveniles are very bright. Young wolf eels are bright orange with spots. Many of the young eels have browner patches along their bodies that give them a burnt look. As the eels mature, the color fades. Eels settle into darker, muddier colors. But each eel retains its own spots.

Baby Wolf Eel
Image by Vancouver Diving Locker

Male wolf eels are grayer, and female wolf eels are browner

Scientists can determine the sex of an adult wolf eel just from its color. Adult males are usually dark gray, blue, or green. Adult females are usually brown or reddish. Male and female wolf eels also have different spot patterns.

two wolf eels
Image by Chris Wilson

7. Wolf eels have the same mates for life

Wolf eels form monogamous relationships. Once a male and female mate, they stay together for the rest of their lives. This is quite rare in nature. After spending their young adulthood in the open water, two mates find a den together, where they spend the rest of their lives. When the female lays eggs, parents take turns leaving the den to hunt while the other partner protects the eggs.

A female wolf eel can lay 10,000 eggs at a time

A single female wolf eel can lay as many as 10,000 eggs at once. After laying the eggs, she will organize them into a neat, spherical pile. She wraps her body around the pile to protect the eggs and keep them warm. The eggs usually hatch 13-16 weeks later, and mom’s job is pretty much done. The young larvae are carried away on ocean currents.

8. Young wolf eels swim in open waters, and settle down in a reef with their mates

Adult wolf eels spend their time slithering through cracks and crevices of coral reefs. But they spend their youth in the open water. When wolf eel eggs first hatch, they float away from their parents on ocean currents. Once the eels are about four months old, they start swimming in the open water around the middle depths of the ocean. As they grow, they migrate to shallow water. Young adults will feed along the ocean floor and explore habitats before mating begins.

two eels in a den
Image by Eva Funderburgh

9. Harbor seals, sharks, and larger fish prey on wolf eels

Wolf eels have several natural predators in the wild. These predators are even bigger and stronger than the wolf eel. They include sharks, larger fish, and harbor seals.  Wolf eels prefer their reef habitats because they can escape through narrow passages among the rocks. But young wolf eels swimming in open water are much more exposed. One scientist once found a sixteen inch wolf eel in the stomach of a salmon.

10. In Some Native Alaskan tribes, only Shamans could eat wolf eels

Wolf eel flesh is edible, and has a sweet, savory taste. Members of the Kootenai and Tlingit tribes of the pacific northwest hunted wolf eels and other wolffish for food. However, in some Native Alaskan cultures, wolf eels were considered “doctorfish.” Only Shamans and healers could eat wolf eels. Tribespeople believed that consuming the wolf fish enhanced the shaman’s healing powers.

Image by Rawpixel Ltd

Despite the wolf eel’s intimidating size, it’s usually friendly towards humans

With their long bodies, huge heads, and sharp teeth, wolf eels can seem very threatening. However, divers know that these animals are not aggressive towards humans. In fact, wolf eels are known for being curious and friendly. It’s not uncommon for a wolf eel to approach divers. Instead of attacking, they usually swim around. Some divers have even been able to “tame” wild eels. These wolf eels, like dogs, enjoy tickles and head scratches. Would you go swimming with a wolf eel?

How endangered is this animal?

Human Impact

Wolf eels are not considered an endangered species. However, their population has likely been declining for several years. Commercial fisheries do not target wolf eels, but human activity has been hurting the wolf eel population for decades.

  • Commercial fishing deprives wolf eels of food and habitats
    Even though there is no commercial industry for fishing wolf eels, they are still hurt by the commercial crabbing industry. Wolf eels feed on crustaceans, such as crabs. Thus, it is common for wolf eels to become trapped in crab traps while hunting. The crab and octopus industries have depleted wolf eel habitats of the eel’s primary food sources. And trawler nets sweeping through reefs destroy coral habitats.
  • Wolf Eels are popular targets among hunters
    Non-commercial fishermen frequently hunt wolf eels, both legally and illegally. Even though there is no wolf eel industry, fishermen target the fish for its delicate white flesh. Sportsmen also enjoy hunting the fish because of its large size and fearsome appearance. On average, sports fishermen catch around 200 wolf eels per year.

Sources

Overview

Also Known As

Anarrhichthys ocellatus

Size

up to 8.2 feet (2.5 m) in length and weight up to 18.4 kg (41 pounds)

Distribution

Eastern Aleutian Islands to southern California; Sea of Okhotsk and the Sea of Japan

Habitat

Usually inhabit rock and stone crevices, dens, and caves in the reefs

Food

Crabs, sand dollars, abalone, sea urchins, clams, mussels, fish, and squid

Lifespan

About 25 years

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