How smart is a giant Pacific octopus? Giant Pacific octopuses are smart: they can learn to open jars. Giant Pacific octopuses can tell individual people apart. A giant Pacific octopus has a well-developed brain. National Wildlife magazine reported that scientists believe octopuses are more intelligent than any fish, though not as smart as most mammals.

In a 2010 study, eight giant Pacific octopuses were each exposed to two unfamiliar people over two weeks; one person fed them, and the other touched them with a bristly stick. By the end of that 2010 study, the octopuses behaved differently toward the two people: a dark eyebar pattern, arm reaching and funnel direction all differed significantly. In the 2010 study, the four larger octopuses changed their breathing rate between the two people, but the four smaller octopuses did not.

A giant Pacific octopus named Pandora opened her first puzzle jar in 15 minutes, and later jars took her about two minutes on average. Unscrewing jars took the octopuses tested a long while to learn, but nearly all of them succeeded in the end. Aquarium researchers suggest that individual giant Pacific octopuses have different temperaments, which could explain why they handled toys for different lengths of time. Researchers report that octopuses explore and may show motor play, such as repeatedly handling objects.

This finding comes from common octopuses, not from the giant Pacific octopus. In a 2020 study of common octopuses, 5 of 6 learned which way to push one arm through a maze to reach food, even without seeing the arm or the food. The 2020 maze study found that octopus learning happens in the brain and is then made available to each arm. The researcher who led the 2020 maze study called the octopus 'an octopus with one brain and eight very clever arms.'

The veined octopus, a relative, carries halves of coconut shell under its body and uses them as portable shelter. Among invertebrates, which are animals without backbones, only octopuses and a few insects are known to use tools, says the Natural History Museum. Scientists still debate how to define a tool, so whether coconut carrying counts is argued.

In a lab study, Octopus insularis, a relative, alternated between quiet sleep, with pale skin and closed pupils, and short active sleep, with changing skin patterns and rapid eye movements, lasting about 40 seconds. In a 2023 study of Octopus laqueus, another relative, brain activity during active sleep resembled brain activity during waking.

A 2021 review by the London School of Economics, drawing on over 300 studies, concluded that cephalopod molluscs, which include octopuses, should be regarded as sentient. After the 2021 review, the UK government said it would extend its Animal Welfare (Sentience) Bill to cover all cephalopod molluscs and decapod crustaceans. A 2022 review by octopus researcher Jennifer Mather argues that octopuses may have the neural basis for consciousness.

The suckers on a giant Pacific octopus's arms help it grip things and taste them. Each sucker on an octopus's arm may have about 10,000 neurons, or nerve cells, to handle taste and touch. Harvard researchers found sensors in octopus suckers that respond to a non-dissolving class of natural chemicals called terpenoids.

The octopus nervous system holds nearly half a billion neurons, more than six times the number in a mouse brain. The vertical lobe of the octopus brain plays an essential role in learning and memory, and is the largest learning and memory center known among invertebrates. The octopus vertical lobe shows long-term potentiation, a strengthening of connections that is important for acquiring long-term memory. According to the Natural History Museum in London, an octopus's brain-to-body ratio is the largest of any invertebrate. Cephalopod and vertebrate brains have evolved independently for more than 500 million years, which makes comparing them a challenge. Octopuses represent an entirely independent experiment in the evolution of large brains and complex behavior.

The first octopus genome to be sequenced, in 2015, was from the California two-spot octopus and has more than 33,000 protein-coding genes. The 2015 octopus genome has 168 protocadherin genes, a dramatic expansion compared with 17 to 25 in some other mollusks. The octopus genome shows extensive mRNA editing that creates transcript and protein diversity in genes involved in neural excitability. Using a molecular clock, researchers estimated that the octopus and squid lineages diverged about 270 million years ago.

An octopus's skin has a top layer of pigment organs called chromatophores that make its colors. A giant Pacific octopus can change the color of its skin to blend in. It can also change the texture of its skin, raising bumps to match its surroundings. Researchers who study how cephalopod skin changes pattern say they do not yet understand all of the neural part and lack enough data. A giant Pacific octopus has sharp vision. Cephalopod eyes can perceive polarized light, light waves vibrating in particular directions, from different directions. Cephalopods, including octopuses, appear to be colorblind, except for a few deep-sea species.

Giant Pacific octopuses are visual hunters, which means they use their eyes to find food, with a variety of hunting strategies. Giant Pacific octopuses are mostly active at night, and they hunt at night. A giant Pacific octopus's food includes crabs, clams, shrimp, scallops, snails and small fish. When it hunts fish, a giant Pacific octopus may use a toxic saliva to paralyze them.

The giant Pacific octopus is the largest kind of octopus in the world. As of November 2026, a full-grown giant Pacific octopus often weighs 50 pounds (23 kg) or more. As of November 2026, the Seattle Aquarium says adult giant Pacific octopuses weigh 40 to 100 pounds, with a relaxed tip-to-tip span of 12 to 14 feet. As of November 2026, an Alaska species guide lists male giant Pacific octopuses at up to 45 kg (100 lb) and 250 cm total length, and females at up to 23 kg (50 lb). As of November 2026, Monterey Bay Aquarium and the Alaska Wildlife Alliance both say the heaviest giant Pacific octopus on record weighed 200 pounds and measured nearly 20 feet across. As of November 2026, National Geographic and National Wildlife magazine both report a record giant Pacific octopus of more than 600 pounds and about 30 feet across, a much larger figure than the 200 pounds other sources give.

Giant Pacific octopuses live from southern California north to Alaska and the Bering Sea, and across the Pacific to Japan. As of November 2026, reference guides disagree about how deep giant Pacific octopuses live: one says to 750 meters, another to 1,000 meters, and others to 1,500 meters. In Alaska, giant Pacific octopuses are both predators and prey in the marine ecosystem.

As of November 2026, giant Pacific octopuses are not considered at risk of dying out: the Georgia Aquarium lists them as Least Concern on the IUCN Red List. As of November 2026, giant Pacific octopus populations are thought to be stable in the North Pacific. In a 2000 volunteer-diver survey of Puget Sound, only 18 octopuses were spotted and reported to the Seattle Aquarium. As of November 2026, National Geographic says the total number of giant Pacific octopuses is unknown. As of November 2026, conservation groups warn that climate change, pollution and fishing are growing threats to giant Pacific octopuses, and that warmer water could disrupt egg development.

A giant Pacific octopus lives about 3 to 5 years. Scientists age octopuses by counting growth rings in hard parts such as beaks and stylets. The rings mark days, not years. A female giant Pacific octopus breeds only once in her life. Giant Pacific octopuses breed near the end of their lives and die not long after. A mother lays her eggs in a den and stays with them, usually not eating, until they hatch. A female lays about 20,000 to 100,000 eggs. The eggs take roughly 5 months to a year to hatch, depending on the water temperature. A baby is about the size of a grain of rice when it hatches. After hatching, the tiny octopuses drift near the ocean surface as plankton. About one percent of giant Pacific octopus larvae survive their drifting plankton stage.

Words to know

• invertebrate: animal without backbone
• potentiation: connection strengthening
• sentient: able to feel
• genome: full gene set
• plankton: drifting life