Anglický text článku
One night in 2016, an octopus called Inky climbed out of his tank in a New Zealand aquarium. Earlier that day, someone worked on the tank and did not close the lid properly. Inky crossed the floor, found a narrow drainpipe and disappeared into the sea. The staff never saw him again, and his escape made the news all over the world.
How can a big animal like that get through such a small pipe? The answer is surprising: an octopus has no bones at all. Its soft body can change shape like water in a bag. The hardest part of the animal is its beak, so an octopus can squeeze through any hole big enough for its beak.
An octopus has three hearts: one sends blood around the body and the other two push it through the gills. Its blood is blue, not red, because it carries oxygen with copper instead of iron. Copper works better than iron in cold water with little oxygen.
An octopus also thinks in a very unusual way. It has about five hundred million nerve cells, the same number as a dog, but two thirds of them are not in its head. They are in its arms, so every arm can taste, touch and decide almost on its own.
Scientists believe that an octopus is colour-blind and sees the world in grey. Even so, it can change the colour of its skin in less than a second to hide on a rock or a plant. Nobody is quite sure how a colour-blind animal knows which colours to copy. Inky did not need to change colour that night; he only needed an open lid and a pipe to the sea.