What do you think of this fact?
If aliens live on Earth, they’re probably in the ocean and have eight arms. The octopus breaks pretty much every rule we know about animals. It is a cephalopod, a kind of mollusk, so its closest relatives are snails and clams rather than fish.
Three hearts instead of one
Two small hearts pump blood through the gills, and one big heart supplies the rest of the body. The weird part: the big heart stops beating when the octopus swims. That makes swimming exhausting, which is why octopuses prefer crawling along the sea floor.
Blue blood, for real
Our blood is red because it contains iron. Octopus blood carries oxygen with a molecule called hemocyanin, which contains copper. The result: blue blood. In cold, low-oxygen water, it actually works better than our system.
The arms think for themselves
An octopus has around 500 million neurons, roughly as many as a dog. But about two thirds of them are in the arms, not the head. Each arm can touch, taste and partly decide on its own what to grab. Think of it as eight roommates who only loosely coordinate.
A severed octopus arm can keep reacting to touch and reaching for food for a while.
As if that weren’t enough: octopuses can change their color and even the texture of their skin in a split second, even though they’re probably colorblind. How exactly they pull that off still isn’t fully understood.
By the way, calamari is squid, not octopus. Squid are strange animals too.