Wolf Eel Profile
One of the earliest fishes described by researchers in California was written about in 1855, and described as “In color, perhaps no more beautiful fish than this has yet been found in our waters.”
The qualifier in this sentence is important because this is one hell of an ugly animal. And that’s unfortunate because it likely distracts most people from how lovely, curious, and intelligent these fish are.
Wolf Eel Facts Overview
| Habitat: | Rocky reefs, caves |
| Location: | Temperate North Pacific (California to Sea of Japan) |
| Lifespan: | 20 years + |
| Size: | Up to 2.4 meters (8.2 feet) long |
| Weight: | Up to 18.4 kilograms (41 pounds) |
| Colour: | Juveniles are bright orange with purple; Adults are grey with dark spots |
| Diet: | Invertebrates with hard shells (crabs, sea urchins, etc.), fish |
| Predators: | Sharks, big fish, harbor seals, rockfish |
| Top Speed: | Not recorded |
| No. of Species: | 1 |
| Conservation Status: | Least Concern (IUCN) |
Wolf eels are large reef predators from the North Pacific. They’re sometimes fished for sport, and often picked up in crab nets, but to recreational divers, they’re best known as misunderstood ocean puppies who like affection and will come out to greet old friends.
These apparently smart, eel-like creatures play an important role in the ecology of the crustaceans they feed on, as well as helping balance populations of other large predators, like giant octopuses.
Interesting Wolf Eel Facts
1. They’re not eels
Eels are members of the bony, ray-finned fish, just like most of the fish you’re familiar with, and the wolf eel, too. They’re generally different from other bony fish in that they have no pectoral or anal fins and, well, they’re eel-shaped.
This might sound like a terribly circular descriptor, but it’s also the one taxonomists used when they came up with the name for eel’s order: Anguilliformes, or “eel-shaped”.
Of course, it’s a bad descriptor for other reasons, too, including that electric eels, swamp eels, and Iggy Pop are all eel-shaped but they’re not members of the order.
Regardless, wolf eels are ‘eel-shaped’, but they’re not Anguilliformes. They’re just regular old fish that look like eels. But don’t worry too much about this, since ‘fish’ isn’t a specific thing either.
To be more specific, wolf eels are in the order Scorpaeniformes, along with scorpionfishes and lionfishes. Incidentally, they’re not wolves, either, but this probably needs less of an explanation.
2. They live in a cave
Many marine eels are a bit strange, in that they don’t swim about much, and rather sit in caves like slippery trolls, ambushing hapless animals as they try to pass.
Wolf eels share this behaviour, and once they’ve picked a mate, they’ll shack up in their little cave, just eating and mating and talking about eel stuff.
3. They’re monogamous
It’s hardly surprising that an animal as ugly as a wolf eel would hold onto a mate for life. Males and females can occupy their caves for years, and between them, can produce up to 10,000 eggs in a clutch.
These eggs will be looked after by both parents, who will massage and rotate them to make sure they’re clean and aerated. While one’s taking care of the babies, the other will take the opportunity to feed.
For a fish, this is a long process. It can take up to 112 days to incubate their eggs, after which, the hatchlings will be at the mercy of ocean currents until they either get eaten or mature. 1 2
4. They like being tickled
Wolf eels definitely have a face for radio, but they’re not as fearsome as they look; at least, not if you’re big enough to be excluded as a prey item.
Divers who frequent wolf eel habitats find them approachable and curious, and they appear to be habituated quite quickly. Some have taken to stroking and scratching the fish under its chin, which it does seem to enjoy, sometimes even coming out of its cave to investigate.
Some say the wolf eel recognises divers who return to the same spot and come out to welcome them, and this could be true. Their habitat contains exceptional biodiversity, and it stands to reason that a member of the community would evolve to tell other members apart quite well.
5. But they can bite
Wolf eels are big animals, and they’re well adapted for crushing the hard shells of their prey with their teeth.
While they’re generally very chilled-out animals, they can and do bite if threatened, and they can pack a punch. Even a decapitated wolf eel can bite, though if you’ve decapitated it, you likely deserved that.
Still, while some of the larger true eels like the Moray can pop your thumb off if you get too close, wolf eels are well renowned for being gentle animals. They even generally tolerate their rivals.
6. They compete for den space with the giant octopus
One of the most intelligent animals in the ocean shares its space with this fish. The giant Pacific octopus is an elite roaming predator in the areas in which the wolf eel makes its home, and the two often meet.
Both of these large animals are soft-bodied and use caves for protection against predators. They don’t appear to be on one another’s menu, but they will defend these caves against one another if their rival gets too close. On occasion, one will drive the other out of the den to take it for themselves.
While both of these animals share a similar resource in the same location, they likely avoid most of their competition by adopting different hunting styles.
This is a form of niche partitioning, and it’s a cheaper way for two animals to exploit the same resource than fighting over it all the time. 3
7. They need the reef
Pollution and destructive fishing practices damage wolf eel habitats, and they’re often caught by skin fishermen and as by-catch in crab pots and trawling nets.
While they are doing okay globally, local populations have been entirely eradicated in some areas, particularly surrounding metropolitan locations. 4
Wolf Eel Fact-File Summary
Scientific Classification
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Scorpaeniformes |
| Family: | Anarhichadidae |
| Genus: | Anarrhichthys |
| Species: | ocellatus |
Fact Sources & References
- Peter Kragh (2014), “Wolf eel eggs hatching and baby wolf eels”, YouTube.
- Winter (2014), “Giant Wolf Eel Encounter”, YouTube.
- Ed Capelle (2020), “Giant Pacific Octopus and wolf eel attack”, YouTube.
- “Wolf-eel”, Monterey Bay Aquarium.