I got a book this summer called Octopus: the Ocean’s Intelligent Invertebrate. If I had time, I would start a religion around worshipping octopuses (not octopi) because they are so cool. But since I have to get back to studying Organic Chemistry, Biology, and writing a paper about Icelandic sagas, I’ll instead pass down some the coolest facts I learned from that book (which y’all should read, after you’re done with the cave book.)
Not only do octopuses have ink and 8 tentacles…they also have beak and poison venom
The beak of an octopus is nestled up under itself, so you can’t see it just by looking at the octopus. Once an octopus gets a hold of a shelled prey, like a crab or a clam, it can either scrape at the shell with its teeth, or my personal favorite, drill a hole with its beak and inject poison venom. All the Caribbean pygmy octopus has to do is bite a crab once, and in moments the crab will be dead.
Octopuses can change skin color or skin texture in 30 milliseconds.
When an octopus is evading a predator or stalking its prey, sometimes it needs to hide. To an octopus, sometimes hiding doesn’t actually mean crawling into a crevice and covering its eyes. To an octopus, this could mean sitting on a rock, and becoming that rock. Octopus skin contains chromatophores – “sacs that contain yellow, red, or brown pigment within an elastic container.” There are also other parts of the skin that don’t produce pigment, but instead reflect light from the environment. Nerves are connected from the chromatophores directly the octopuses brain, so in less than 100 milliseconds the octopus and trigger a color change. Along with a color change, small muscles in the octopus’s skin and contract or release, altering its texture.
An octopus’s arm is like an extension of its brain…and there are 8 of them
Over half an octopus’s neurons are not confined to its brain – in fact, they’re in the arms. Octopus arms are highly specialized. They’re uber flexible, super sensitive, and incredibly dexterous. They can squeeze into tight crevices, support the octopus as it “walks” across the ocean floor, and the individual suckers can even untie surgical string, as one lab scientist discovered.
They can detach an arm on purpose, to get away from a predator or reach some food.
Sometimes, when an octopus feels threatened or really wants a little hermit crab that it can’t physically reach, it will pop off an arm (no big deal). In the feeling threatened case, this may help the octopus be less accessible to a potential predator, since it has one fewer arm to gnaw on. In the hermit crab case, the arm will travel a short distance, snag the crab, and transport it down the arm, from sucker to sucker, so that the octopus can reach it.
The whole “losing an arm thing” isn’t a big deal, because they can just regenerate the arm
Basically what I’m trying to say is that an octopus is closer to bring a Time Lord than you will ever be. When an octopus loses an arm, either by detaching it itself or to a predator, the bleeding is minimal because octopuses have direct nervous control of blood vessels, and can staunch the bleeding themselves. A blood clot develops, and the octopus adjusts itself to relieve tension. Slowly, a new arm grows from the stub, with chromatophores arriving last.