Octopuses, which for the record is the correct pluralization of octopus. (It can also be octopodes, since the word is Greek in origin, but never octopi.)
Blue Bloods
“For starters, octopuses have literal blue blood. There’s a common misunderstanding that human blood is blue inside your body when it’s deoxygenated, but that comes from the fact that your veins look blue through your skin. Deoxygenated blood is still very red because of the iron-based mechanism by which our bodies transport oxygen molecules. Octopuses said ‘no, thanks’ to iron blood, though, and swapped in a copper-based protein that binds oxygen instead. It’s more efficient than iron in the cold, low-oxygen environments that most octopuses live in. It sure does make them spookier, but they’re not alone. The ocellated icefish has clear blood and there are lizards that run green. Both are from Earth.”
An octopus just hangin’ out, Pixabay
Octopuses’ brains are in their arms
“Two-thirds of an octopus’ neurons reside in the long appendages (tentacles). This decentralized way of thinking means that even severed arms can “think” for themselves, or at least respond to physical stimuli and try to escape whatever is trying to eat them, which is why people die from trying to swallow live octopus arms only to find that the arm is still fighting back (a reported six people die this way on average each year in South Korea, where the dish is popular).”
Intelligent
But their peculiar approach to brains hasn’t stopped them from ranking among the most intelligent creatures that we know of. Octopuses regularly use tools, solve puzzles, and generally cause mayhem by sneaking in and out of their enclosures. They also sometimes accessorize by hopping inside old coconut shells and using them as little mobile homes, all while looking more stylish than most humans.
Suckers and 3 Hearts
As they travel, they also taste everything that they walk on since their suckers are all sensory organs. You’d think that would motivate them to swim everywhere, but unfortunately one of their three hearts has to stop beating whenever they swim, which is quite tiring and means that many octopuses prefer to stroll. Their other two hearts provide blood to the gills, but that third heart circulates blood to the central organs.”
“The main organs reside inside the octopus’ bulbous head (called a mantle), which contains no bones. The only truly hard part of an octopus is the beak, which is basically its mouth. This means that the critters can squeeze through almost any opening as long as it’s bigger than the schnoz. Everything else is negotiable.”
Short Life
“But perhaps the weirdest thing about octopuses is that, unlike many of the other highly intelligent creatures populating our planet, they don’t live long. Some live just six months, others a few years, and most males die shortly after mating. The females last long enough to protect their clutch of eggs, during which time they slowly starve to death.”
CURIOUS to the MAX 
Thanks to my querulous nature (‘whadda ya mean, octopi is not a word? It’s a main ingredient of cioppino pie’), I looked it up in my dictionary, which agreed with you. Dang! Then I looked farther and found the word ‘octroi’ — perfect for the game dictionary: a tax levied on goods when they enter a town. Knew they were intelligent but didn’t know about brains in their arms, three hearts, and thet they’re short lived; does that mitigate dining on them? (Well, it was going to die soon anyway.)
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Jack,
Their short life does mitigates dining on them, however the three hearts kinda has the opposite effect. And if octopi is in your cookbook, go ahead and use it, who would want to throw away that recipe (well, me, not sure I want to eat octopi).
I like the “octroi” find and will see if I can use it-somewhere.
Peggy
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Dear querulous,
It’s better to die a natural death than by “tooth” or octroi.
j.
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I pretty much stopped reading at “eating live octopus arms.” I’ll stick with p & j, thank you.
OK, I’ve gotten beyond that section. Yes, they’re brilliant creatures and they can be different colors. I’ve seen blue octopuses gliding along the ocean floor – via video, of course.
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Shari,
Nice! Pink and purple too.
Peggy
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So all these decades, I’ve been wrong every time I discussed ‘octopi’. Luckily, it’s not a topic that has come up too often during my life!
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Jacqui,
They are interesting, though 🙂
Peggy
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Jacqui,
“Octopi” didn’t come up often cuz you’re a vegan?
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I never knew that the octopus was so intelligent – but then again I think generally speaking, we humans tend to assume we are so much more intelligent than non humans. We also tend to forget that they are sentient beings! Lots of interesting information here … the only fact I already knew was the blue blood ~ as I’ve seen, though not eaten dishes that have squid ink in them – it looks black! I guess it’s considered a delicacy in some cultures. Definitely fascinating creatures to be sure!
Peta
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When I lived in Greece octopus and squid were always on the menu. After I learned how smart and incredibly creative Octopus were I don’t eat them. They have very kind eyes and have been much maligned in literature! jw
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What a lot of very interesting information! Particularly the part about how intelligent these creatures are. It seems like humans consistently underestimate non humans…. both with regard to their intellect and to the fact that they are sentient beings.
I did know about the blue blood, because I’ve seen seafood dishes made with squid ink and it looked black! Such short lives, surprising fact indeed.
Peta
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Peta,
I know, humans have let being successful go to their heads.
Peggy
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