Which sea creature has more than one brain?

And the answer: octopus.    
Photo credit: public domain.

With a central brain in their heads and each arm possessing an additional small brain, the octopus has brain-building proteins that are typically only found in humans and other vertebrates. They have up to 500 million neurons, about 30% of which are in their central brain.

What has three hearts, nine brains, and blue blood? No, it’s not a setup to a bad joke—it’s the octopus! These unusual creatures have a biological composition unlike most other species on the planet, yet it’s perfect for their unconventional lifestyles. Two out of three of the octopus hearts are used to pump blood to the gills, while the third, larger heart circulates blood to the rest of the body. Meanwhile, in addition to the central brain, each of the octopus’s 8 arms has a mini-brain, thus allowing that arm to act independently. Octopus’s blue blood is a result of adaptation to cold, low-oxygen water, and uses hemocyanin—a copper rich protein.

What’s more, octopuses are masters of optical illusion. Along with squid and cuttlefish, octopuses can actually change their skin texture, skin dimensionality and, of course color, to match and blend in with their surroundings. Incredibly, octopuses are able to accurately camouflage themselves to just about anything—and they do it by sight, not touch. The kicker? These creatures are actually colorblind, leaving scientists baffled as to how they match their surroundings with impressive stealth.

Did you know?

Yesterday, October 8, was World Octopus Day! This eight-legged, mysterious creature from the sea has long been a source of inspiration and intrigue. Despite their relatively short lifespan, octopus fossils date back more than 300 million years, meaning that they pre-date even dinosaurs. In large part, the long-term survival of the octopus species is attributed to their high intelligence—with around 500 million neurons located in their brains and arms, they are able to circumvent their instincts, learn lessons, and solve problems in a manner unique to any other ocean species. Some octopuses have even been seen getting creative, using discarded coconut shells and making them into mobile homes!

Learn more about the octopus here.


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