The octopus is one of nature’s most delightful oddities: an eight-armed, wildly intelligent, oddly graceful creature that’s fascinated storytellers, chefs and cephalopod fans for generations. How much do you know about my favorite sea citizen? Find out with these fun octopus facts.
1. They’re arms, not tentacles
Despite what you’ve heard, the extremities of an octopus really are arms. An octopus has four pairs of them, and they all move independently, with a highly sophisticated nervous system — two thirds of an octopus’ neurons are in its arms. This allows them to grasp and grapple potential prey and objects they want to manipulate much more easily, and it makes for a great dinner table story.
2. Octopi can fit through almost anything
As long as an aperture is large enough for an octopus’ beak, it’s on. Watch this amazing video of an octopus moving through a series of plexiglass tubes, which showcase the animal’s incredible muscles as it slips through quarter-sized openings. That trait comes in handy for octopi living in captivity, who have been known to confound zookeepers with their escape skills.

3. My, what tasty suckers you have, dear
Octopi have a pretty impressive set of incredibly strong suckers, but did you know that they can taste objects through their suckers? This helps them get a better sense of their surroundings, discriminate between friend and foe, and, you know, get a preview of dinner.
4. Octopi use tools
Tool use is extremely rare among animals, and it’s kind of a big deal. So when octopi were observed building shelters for themselves out of coconut shells, their tiki style made humans sit up and take notice. The animals are clearly making a conscious decision to carry and use the shells, illustrating that they understand tool use and know how to use the environment around them to their advantage.

5. Octopi can regrow their arms (but arms can’t grow into octopi)
You might already know this, but it bears repeating: if an octopus loses an arm, she can regrow it, which is a pretty nifty trick. Octopi can actually drop their arms to confuse predators, although this is a plan of last resort since growing new ones takes a while. Thanks to the concentration of neurons in their arms, the detached arm can keep wriggling in a rather convincing way while the octopus escapes to safety.
6. The more to love you with
Octopui have a grand total of three hearts. Seem like too many to you? Two of them are devoted exclusively to circulation throughout the body, and the third circulates oxygen through the organs. While octopi swim, this third heart doesn’t beat, which cuts down on their stamina, which explains why crawling through the water is preferred to cruising.
7. Octopus ink is an irritant
While cooks use octopus ink (along with inks from other cephalopods like cuttlefish) and it’s by no means toxic, it is an irritant. It’s designed to confuse enemies not just by clouding the waters, but also mangling the vision, sense of taste, and smell of predators so the octopus has time to get away.

8. Octopuses, octopi, or octopodes?
Ah, the great debate. “Octopus” comes from Ancient Greek, which had a perfectly acceptable plural form: “octopodes.” English speakers (via Latin) turned it into “octopi” but many authorities generally agree that “octopuses” is the most reasonable pluralization. Where in the heck did “octopi” come from? In Latin, the “-us” ending would be pluralized with an “-i,” but since this word isn’t Latin, the point is moot. Unless, of course, you just really like saying “octopi.”

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