Giant Pacific Octopus
Enteroctopus dofleini
The biggest octopus in the world, with a taste for crabs and, now and then, a small shark.
The giant Pacific octopus lives in the cold water of the North Pacific, from Mexico's Baja California up to Alaska and across to Japan. It's the largest octopus there is: a typical adult weighs 10 to 15 kilograms, and its arms can reach across a small room. It spends the day tucked into a den among the rocks and comes out to hunt, and it lives only about three to five years.
On the conservation status
Least Concern on the IUCN Red List (assessed in 2014, published in 2018). But the IUCN says nobody knows whether its numbers are going up or down, and asks for more research on how many there are and how fishing affects them.
- Weight
- Usually 10–15 kg (22–33 lb)
- Arm span
- Typically 2–4 m (7–13 ft)
- Lifespan
- About 3–5 years
- Diet
- Crabs, clams, fish, even small sharks
- Depth
- Mostly above 110 m, but as deep as 1,500 m
- Home
- Cold North Pacific, Japan to Baja California
The good stuff.
The biggest octopus of all
Most adults weigh 10 to 15 kg, but some grow much bigger. The largest one scientists have actually weighed was about 71 kg (156 lb) and nearly 4 m long. Stories of 270 kg animals with arms 9 m across have never been properly measured.
It changes colour and texture
Its skin is usually reddish-brown, but tiny colour cells can turn it white, red or mottled in a moment. It can also raise little bumps on its skin, so it can look like a rock or a patch of seaweed.
Shark for dinner
Mostly it eats crabs, clams and fish, using its arms and a hard beak to open shells. It will eat nearly anything it can catch, and in aquarium tanks, giant Pacific octopuses have even caught and eaten dogfish sharks.
A mother who stops eating
A female lays tens of thousands of eggs in a den and stays with them for about six months in the cold water, cleaning them and keeping fresh water flowing over them. She doesn't leave to eat, and she dies soon after they hatch.
Tiny drifters
A newly hatched octopus is only about a quarter of an inch long. At first the babies drift in the plankton near the surface, and only when they're bigger do they settle on the seabed to live like their parents.
Arms that grow back
If a crab, a seal or a fish bites off an arm, an octopus can grow it again. Octopuses studied in labs rebuilt a lost arm, nerves and suckers included, over a few months.
Wait, really?
- ✦
In Washington State, it's against the rules to take an octopus at eight popular dive sites in Puget Sound, so divers can visit the same animals again and again.
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A different octopus, a deep-sea species named Graneledone boreopacifica, holds the record for guarding eggs: over four and a half years. A giant Pacific mother stays about six months.
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Sea otters, harbor seals and Pacific sleeper sharks all hunt it.
What it sounds like
Silent. Octopuses have no known calls of any kind.
Where you might see one
Rocky shores and kelp forests from Baja California to Alaska. The Monterey Bay Aquarium in California and the Seattle Aquarium in Washington both show them, and in Puget Sound, divers meet them at the protected dive sites.
The trouble
- Fishing pressure, which scientists still need to measure
- Being caught by accident in crab and fish traps
- Being taken from the shallow places where divers see it
One real thing
Giant Pacific octopuses are protected at some dive sites, so if you ever go snorkelling or diving where they live, look and take photos, but leave them in their dens. Wild octopuses can't be kept happily at home.
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