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.

Most observations of octopus intelligence have come from captivity, because divers cannot stay down long enough to watch complex behavior in the wild. Giant Pacific octopuses are hard to study because they live short lives and keep out of sight.

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.

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.'

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. Researchers report that octopuses explore and may show motor play, such as repeatedly handling objects. Aquarium researchers suggest that individual giant Pacific octopuses have different temperaments, which could explain why they handled toys for different lengths of time.

The veined octopus, a relative, carries halves of coconut shell under its body and uses them as portable shelter. To study the veined octopus's coconut carrying, researchers spent 500 diver hours watching and observed 20 veined octopuses. 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.

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.

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. 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.

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. 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.

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.

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. 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. Demand for octopus as food has raised its value as bycatch in pot-gear fisheries.

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.

Words to know

• neurons: nerve cells
• sentient: able to feel
• protocadherin: cell-sticking gene
• bycatch: unintended catch
• plankton: drifting life