Animal
Giant Pacific octopus
The giant Pacific octopus is the biggest octopus in the world. It has eight long arms, three hearts and blue blood.
The giant Pacific octopus is the largest octopus species in the world, living in cool waters of the North Pacific from Japan to Alaska and California. It hunts crabs and clams at night, changes color and skin texture at will, and can squeeze through a hole only a few centimeters wide.
Enteroctopus dofleini is the largest octopus species, typically 10 to 50 kilograms, found around the North Pacific from the intertidal zone to about 1,500 meters. A generally nocturnal, solitary generalist predator with three hearts and copper-based blue blood, it lives about three to five years; females brood up to 100,000 eggs for months without feeding.
Photo: NOAA/R. N. Lea [1], public domain, via Wikimedia Commons
Meet the giant Pacific octopus
The giant Pacific octopus is the biggest octopus of all.
It has eight long arms with suckers. It can be pale gray or dark red. It has three hearts and blue blood.
The giant Pacific octopus is the largest octopus species in the world. Adults usually weigh about 10 to 50 kilograms, and a relaxed adult can measure 3.7 to 4.3 meters from the tip of one arm to the tip of the opposite arm, about as long as a small car.
It is a mollusc, a relative of snails and clams, with a soft body and no bones. Its only hard part is a beak, shaped like a parrot's. It has three hearts, blue blood, and skin that can turn from pale gray to dark red.
Enteroctopus dofleini, in the family Enteroctopodidae, is the largest octopus species. Alaska's Department of Fish and Game gives adult weights of 22 to 110 pounds (about 10 to 50 kilograms), with a record of 156 pounds measured by Canadian researchers; the Seattle Aquarium gives a relaxed tip-to-tip span of 12 to 14 feet.
Two hearts pump blood through the gills and a third pumps it around the body. ADF&G explains that the blood is blue because of hemocyanin, a copper-rich protein. Layered chromatophores, or pigment cells, let it shift from pale gray to dark red, and muscular knobs change its skin texture.
Quick facts
- Group
- Invertebrate
- Length
- 3.7 to 4.3 m
- Weight
- 10 to 50 kg
- Lifespan in the wild
- 3 to 5 years
Where it lives
The giant Pacific octopus lives in the cold North Pacific Ocean.
It lives near Japan, Russia, Alaska, Canada and the United States. It hides in a rocky den.
This octopus lives in cool waters around the North Pacific Ocean: from Japan and Korea in the west, past Russia and Alaska's Aleutian Islands, and down the coast of North America to Baja California in Mexico.
It can live in rock pools at the shore or deep down, as far as 1,500 meters below the surface. It makes its den under boulders and in rock crevices, often where muddy or sandy sea floor is mixed with big rocks, and it is especially common near thick kelp forests.
The IUCN global assessment (assessed 2014, published 2018) lists native populations in British Columbia, Japan, North and South Korea, Baja California, Russia and the US states of Alaska, California, Oregon and Washington, from 0 to 1,500 meters. Alaska's Department of Fish and Game notes that it lives from shallow subtidal waters to 1,000 to 1,500 meters in the south of its range, and from the intertidal zone to at least 100 meters in the north.
Animal Diversity Web describes ideal habitat as soft mud, sand or gravel with large boulders for dens, with higher densities near dense kelp, and optimal temperatures of about 7 to 9.5 °C.
Its habitat
Where can you find this animal?
- Lives here naturally · Countries and seas named by a scientific source
- Sightings recorded · Records of wild sightings (GBIF)
Lives here naturally · Countries and seas named by a scientific source
Cool coastal and deep waters of the North Pacific, from Japan, Korea and Russia across to Alaska and down to British Columbia, Washington, Oregon, California and Baja California, from the shore to about 1,500 meters deep. Only the coasts of each country shown.
Places: Pacific Ocean, Canada, Japan, North Korea, South Korea, Mexico, Russia and United States.
Source: iucn-red-list · checked October 2026
Sightings recorded · Records of wild sightings (GBIF)
Counts of GBIF records of wild observations (human and machine) and preserved specimens. Records include introduced populations, vagrants, escaped or released animals and misidentifications, so a country with records is not necessarily part of the native range.
Wild sightings have been recorded in United States, Canada, South Korea, Japan, Russia, Colombia, Mexico, South Africa and 17 more places.
Source: gbif · checked October 2026
Range maps show where scientists say an animal lives, often country by country. An animal may live in only part of a country shown, and sightings records can include animals that wandered far from home.
A hungry hunter
The giant Pacific octopus eats crabs, clams and fish.
It hunts at night. It pulls shells apart to get the food inside. It leaves the empty shells outside its door.
Giant Pacific octopuses are carnivores with big appetites. They eat crabs, especially Dungeness crabs, shrimp, clams, scallops, squid, fish and even other octopuses. They usually hunt at night.
An octopus feels and holds prey with its suckers. It can pull crab and clam shells apart, and it may paralyze fish with toxic saliva before eating them with its beak. It carries food back to its den, and the empty shells pile up outside. Divers can find octopus dens by looking for these piles, called middens.
The diet is broad: crustaceans, with Dungeness crabs a favorite, bivalves, squid, other octopuses and fish, and it will scavenge larger fish and birds (ADF&G, Seattle Aquarium). The Seattle Aquarium reports that an octopus eats 2 to 4 percent and gains 1 to 2 percent of its body weight a day.
Hunting is generally nocturnal. Prey is found and held with the suckers; ADW says each pair of arms carries up to 280 suckers with thousands of chemical receptors, giving an acute sense of touch and taste. Shellfish may simply be pulled apart, while fish may be immobilized with toxic saliva and torn with the beak. Prey is taken back to the den, and the remains form middens at the entrance, which researchers examine to study the diet.
Did you know?
Its blood is blue!
Giant Pacific octopus blood is blue because of a copper-rich protein called hemocyanin.
Hemocyanin, a copper-rich protein, gives the blood its blue color (ADF&G).
A soft giant
The octopus's soft body has no bones.
It can squeeze through a hole the size of a lemon! Its suckers can feel and taste. It squirts ink to hide.
The giant Pacific octopus's bulbous mantle holds most of its organs. Each of its eight arms carries about 200 suckers, which find and hold food and can also feel and taste.
With no bones, its body can squeeze through very small gaps. The only limit is its hard beak: if the beak fits, the rest follows. A fully grown octopus can pass through a hole the size of a lemon. When threatened, it squirts a cloud of dark ink that hides it from predators.
The bulbous mantle contains most organs (ADF&G). The Seattle Aquarium counts about 200 suckers on each arm, and ADW says the suckers carry thousands of chemical receptors for touch and taste. The parrot-like beak is the only hard part of the body, so an octopus can pass any gap large enough for its beak; ADF&G notes a 50-pound octopus can fit through a two-inch hole. Sources differ on the beak's material, described as keratin (ADF&G) or chitin (Seattle Aquarium).
Sepia-colored ink, jetted as a screen, confuses predators. Chromatophores change its color and knobs of muscle change its texture; the Seattle Aquarium says color changes express mood, comfort and intentions to nearby animals.
Eggs in the ceiling
A mother octopus hangs her eggs from the roof of her den.
She guards them and keeps them clean for months. The babies are as small as a grain of rice.
Near the end of their lives, giant Pacific octopuses look for a mate. About 40 days after mating, a female finds a rocky den and lays up to 100,000 eggs in long strands hanging from the ceiling. She stays with them for up to six months, cleaning them and blowing fresh water over them with her siphon. She does not leave to eat.
The babies hatch about the size of a grain of rice and drift near the surface for weeks or months. Then they settle on the sea floor. Both parents' lives end soon after mating and hatching.
ADF&G describes a mostly solitary life in which an octopus seeks a mate near its end: males pass a spermatophore into the female's mantle and die a few weeks later. About 40 days after mating the female lays up to 100,000 eggs in strands in a rocky den; ADW gives 20,000 to 100,000 rice-shaped eggs in clusters of 200 to 300 hung from the den ceiling. She guards, cleans and aerates them for up to about six months while fasting, and dies about when they hatch. ADW notes incubation can stretch from 150 days to almost a year in cold water.
Hatchlings, about the size of a grain of rice, live as plankton (paralarvae) near the surface for weeks to months before settling (ADW: 1 to 3 months). ADF&G thinks the lifespan is three to five years; ADW gives an average of 4.5 to 5 years in the wild.
Curious and clever
The giant Pacific octopus is curious and clever.
It can open jars and solve simple puzzles. In aquariums, it can tell people apart.
Giant Pacific octopuses usually live alone, often staying in the same den for weeks. They are curious and active. Octopuses have unscrewed jar lids from inside the jar, and captive ones solve simple puzzles, open childproof bottles and use shells and stones as tools.
There is also evidence that captive octopuses recognize individual people and treat different keepers differently. Some have escaped from their tanks and then come back. Their color changes can show mood and intentions to animals nearby.
The species is solitary and den-bound for weeks at a time, emerging to feed, mate or escape. Alaska's Department of Fish and Game reports that octopuses have the greatest brain-to-body-size ratio of any invertebrate, and that captive giant Pacific octopuses recognize individual people, solve simple puzzles, open childproof bottles, use shells and stones as tools and sometimes escape tanks and return.
Octopuses are the only invertebrate group named in the Cambridge Declaration on Consciousness as having the neurological substrates of consciousness (ADF&G). The Seattle Aquarium describes color change as expressing mood, comfort and intentions. Their short lives and reclusive habits make wild research difficult.
Did you know?
This octopus has three hearts.
Two of its hearts pump blood through the gills, and the third pumps it around the body.
Two branchial hearts and one systemic heart circulate hemocyanin-rich blood (ADF&G).
Octopus and people
Giant Pacific octopuses are not in danger.
Nobody knows exactly how many there are. Aquariums help people learn about them.
The IUCN lists the giant Pacific octopus as Least Concern, but no one knows how many live in the North Pacific. They are hard to count because they hide and live only a few years.
As more people want them for food and as bait, more are being caught, including as bycatch in fishing gear meant for other animals. The Seattle Aquarium collects a limited number each year with a permit, then return them to the wild when they are ready to mate, so they can finish their life cycle.
The IUCN global assessment lists E. dofleini as Least Concern with an unknown population trend, naming fishing and harvesting of aquatic resources as the threat. ADF&G notes that North Pacific population sizes are unknown, while rising demand for food and bait has increased its value as bycatch and the number caught across the Pacific.
Predators include sea lions, seals, fish, birds and people. Under a state permit, the Seattle Aquarium collects a limited number each year and returns them to their collection site when they mature, typically after about 12 months, so they can reproduce.
IUCN Red List
How is the giant pacific octopus doing in the wild?
- Least Concern (this animal)
- Near Threatened
- Vulnerable
- Endangered
- Critically Endangered
- Extinct in the Wild
- Extinct
Least Concern
Not at risk of disappearing from the wild right now.
See the IUCN Red List assessment · The IUCN Red List of Threatened Species 2022.2
Amazing facts
-
This octopus has three hearts.
Two of its hearts pump blood through the gills, and the third pumps it around the body.
Two branchial hearts and one systemic heart circulate hemocyanin-rich blood (ADF&G).
-
Its blood is blue!
Giant Pacific octopus blood is blue because of a copper-rich protein called hemocyanin.
Hemocyanin, a copper-rich protein, gives the blood its blue color (ADF&G).
-
A big octopus can fit through a hole the size of a lemon.
Its only hard part is its beak, so a fully grown octopus can squeeze through a lemon-sized hole.
ADF&G reports that a 50-pound octopus can pass through a two-inch hole.
-
Octopuses in aquariums can open jars.
Octopuses have unscrewed the lids of jars, even from inside the jar.
Captive octopuses open childproof bottles, solve simple puzzles and use shells and stones as tools.
Words to know
- mollusc
- a soft-bodied animal such as a snail, clam or octopus
- beak
- the hard, parrot-shaped mouth of an octopus
- hemocyanin
- a copper-rich protein that makes octopus blood blue
- midden
- a pile of leftover shells outside an octopus's den
- chromatophore
- a pigment cell in the skin that helps an octopus change color
- paralarva
- a newly hatched octopus that drifts in the open water
Discovery challenge
-
How many hearts does this octopus have?
How many hearts does a giant Pacific octopus have?
How many hearts pump the giant Pacific octopus's blood?
- One
- Two
- Three
Show the answer
Three
It has three hearts!
Two hearts pump blood to the gills and one pumps it to the rest of the body.
Two branchial hearts and one systemic heart.
-
What color is octopus blood?
What color is the blood of a giant Pacific octopus?
What color does hemocyanin give octopus blood?
- Red
- Blue
- Green
Show the answer
Blue
Octopus blood is blue.
It is blue, because of a copper-rich protein called hemocyanin.
Blue, from copper-based hemocyanin.
-
What is the only hard part of an octopus?
What is the only hard part of a giant Pacific octopus's body?
Which structure limits the size of gap an octopus can pass?
- Its beak
- Its backbone
- Its shell
Show the answer
Its beak
Its beak is the only hard part.
The parrot-like beak is its only hard part, so if the beak fits, the octopus fits.
The beak; any gap that admits it admits the whole animal.
-
Who guards the octopus eggs?
Who looks after giant Pacific octopus eggs until they hatch?
Which parent broods the eggs?
- The mother
- The father
- A crab
Show the answer
The mother
The mother guards her eggs for months.
The mother guards, cleans and aerates her eggs for up to six months without eating.
The female broods alone while fasting; the male dies weeks after mating.
Places where you might see it
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Watch
Country
Japan
Japan is an island country in East Asia. Most of its land is steep mountains and forest, Mount Fuji is its tallest peak, and about 124 million people live there, many of them in big cities such as Tokyo.
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Watch
Country
Canada
Canada is the second-largest country in the world, stretching across the north of North America from the Atlantic to the Pacific and up into the Arctic. It has the Rocky Mountains, thousands of islands and about 42 million people, who speak English, French and many other languages.
Experiments to try
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3D
Animal
Common octopus
The common octopus is a soft-bodied mollusc with eight sucker-lined arms. It lives in coastal waters, hides in a den by day, hunts snails and clams at night, and can change its color, skin texture and shape to vanish against rocks or sand. It lives only one to two years.
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Watch
Country
Japan
Japan is an island country in East Asia. Most of its land is steep mountains and forest, Mount Fuji is its tallest peak, and about 124 million people live there, many of them in big cities such as Tokyo.
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Watch
Country
Canada
Canada is the second-largest country in the world, stretching across the north of North America from the Atlantic to the Pacific and up into the Arctic. It has the Rocky Mountains, thousands of islands and about 42 million people, who speak English, French and many other languages.
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Animal
Sea otter
The sea otter is a marine mammal of the North Pacific coast that spends almost its whole life in the water. It has the thickest fur of any animal, floats on its back to eat, and even uses rocks as tools. By eating sea urchins, sea otters help kelp forests stay healthy.
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Giant squid
The giant squid is one of the biggest animals without a backbone. Most of its length is two very long, stretchy feeding tentacles. It lives deep in oceans around the world, and it is so hard to find that the first photos of a living one in the wild were taken only in 2004.
- Watch What If? Lab What if you had no bones? An adult has 206 bones. They hold the body up, guard the brain, heart and lungs, and give muscles something to pull on. Imagine a body with no bones, then meet animals like the octopus that really do live without them.
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Animal
Greater blue-ringed octopus
The greater blue-ringed octopus is a small octopus that lives among rocks and reefs in the western Pacific. Most of the time it hides, but when it is bothered, about 60 blue rings flash on its skin. The bright rings are a warning, and they tell us this is an animal to watch, never to touch.
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3D
Animal
Japanese spider crab
The Japanese spider crab is a gentle giant of the sea floor off Japan. Its body is only about the size of a large pizza, but its legs can stretch almost 4 meters from claw tip to claw tip, more than any other crab. It crawls slowly along the bottom, eating dead animals and plants.
For parents & teachers
What children will learn
- Describe what makes the giant Pacific octopus the largest octopus and where it lives.
- Explain its body features: three hearts, blue blood, beak and suckers.
- Describe the octopus life cycle and the mother's care of her eggs.
- Discuss evidence of octopus intelligence from aquariums.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- Why might having no bones be useful for an animal that lives among rocks?
- What do you think it means for an animal to be intelligent?
- Why might it be hard for scientists to count octopuses in the wild?
Try at home or in class
- Cut a hole the size of a lemon in a piece of cardboard and imagine a 50-pound octopus squeezing through it.
- Measure 4 meters on the floor to see the arm span of a relaxed adult giant Pacific octopus.
Key vocabulary: mollusc, beak, hemocyanin, midden, chromatophore, paralarva
Where these facts come from
- The IUCN Red List of Threatened Species , International Union for Conservation of Nature (IUCN terms of use (no redistribution of Red List data or range maps))
- GBIF Backbone Taxonomy and GBIF Occurrence Search , Global Biodiversity Information Facility (CC0 1.0 (backbone); occurrence counts are facts derived from records under CC0, CC BY and CC BY-NC)
- Enteroctopus dofleini, global assessment , IUCN Red List of Threatened Species
- Giant Pacific Octopus species profile , Alaska Department of Fish and Game
- Giant Pacific octopus , Seattle Aquarium
- Enteroctopus dofleini (giant Pacific octopus) , Animal Diversity Web, University of Michigan Museum of Zoology
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Wikimedia Commons , Wikimedia Foundation (Per file: Public domain, CC0, CC BY or CC BY-SA only (credited on each page))
Checked, not yet human-reviewed. Last updated October 28, 2026. Spotted a mistake? Tell us.