Let’s learn about octopuses

However strange you think these creatures are, they’re stranger

With three hearts that pump blue blood, color-changing skin and defensive ink jets, octopuses are more fantastical than many fictional aliens.

Brent Durand/Moment/Getty Images

Octopuses are about as strange as any fictional aliens we might dream up.

Each of these soft-bodied cephalopods has eight arms attached to its head. And each of those arms is lined with hundreds of suckers that taste what they touch.

Three hearts pump blue blood throughout an octopus’s body. And pigment-holding cells in octopuses’ skin allow the animals to change color at will. That way, octopuses can blend into their surroundings to avoid predators such as seals, fish and eels. Octopuses can also distract or scare off predators by blasting out plumes of black ink.

Despite having bodies so different from our own, octopuses are not completely unlike us. They’re quite smart, with some brain waves that resemble our own. They can use tools, navigate mazes and solve puzzles. They’re even known to play. Octopuses also seem to remember painful experiences.

Those signs of octopus smarts have led some scientists to say these animals are sentient. That is, octopuses may be aware of their own feelings and experiences. Scientists hope that better appreciating animals’ complex internal lives might lead people to treat them with more care.

Want to know more? We’ve got some stories to get you started:

Here’s why thousands of octopuses gather at the ‘Octopus Garden’ (comic) Underwater cameras and other instruments investigated why so many pearl octopuses gather here to mate and nest. (3/4/2024) Readability: 8.2

Touching allows octopuses to pre-taste their food Special sensory cells in their arms’ suckers sense chemicals. Those cells allow them to taste the difference between food and poison. (1/4/2021) Readability: 7.1

Analyze This: Octopuses may use favorite arms for grabbing meals Understanding how octopuses control all their arms could provide clues for engineers building soft robots. (10/28/2022) Readability: 6.2

Octopuses in the “active” sleep stage ripple with color.

Explore more

Scientists Say: Octopod

Splatoon characters’ ink ammo was inspired by real octopuses and squid

Deep-sea mining could imperil rare, ghostlike octopus

Deep-sea expedition led researchers to doomed octopus nursery

Science is just starting to understand what animals feel

Underwater mountains in the Pacific Ocean may be home to 20 new species

Invertebrates are pretty clever, but are they conscious?

RNA editing helps octopuses cope with the cold (from Science News)

Octopus, squid and cuttlefish arms evolved to ‘taste’ different compounds (from Science News)

Octopuses and squid are masters of RNA editing while leaving DNA intact (from Science News)

Scientists have now recorded brain waves from freely moving octopuses (from Science News)

Octopus sleep includes a frenzied, colorful, ‘active’ stage (from Science News)

Activities

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Explore the wonders of octopuses, squids, cuttlefish and other cephalopods with Science Friday activities! Relax with digital cephalopod coloring books, experiments modeling cuttlefish skin or squid jet propulsion, and much more.

Maria Temming is the Assistant Managing Editor at Science News Explores. She has bachelor's degrees in physics and English, and a master's in science writing.