Common octopus: The deep-sea Einstein that opens jars and solves mazes

The common octopus is the best-studied species in its family and a "deep-sea Einstein" recognised by scientists. It opens jars, solves mazes and mimics other animals, with learning abilities that astonish researchers. Let's meet it.

How clever it is

In the laboratory, a common octopus can learn to unscrew the lid of a glass jar to get the food inside, remember the route through a maze, and change its posture and colour to mimic another sea animal and startle a predator. Its short-term memory and learning are very rare among invertebrates.

Its body

The common octopus's skin is packed with thousands of colour cells, plus tiny bumps called papillae that it can raise. With these two "pieces of equipment" it can make its skin look exactly like a reef within seconds — not just the colour, but even the rough texture. It has three hearts: two pump blood through the gills and one serves the body. Its blood carries oxygen using a copper-based protein, so it is blue.

Where it lives and what it eats

The common octopus is a carnivore, feeding on crabs, shrimps, shellfish and small fish. It often works among rocks, using its arms to explore crevices and catch prey. It lives in warm seas worldwide, from shallow water to greater depths.

A note for grown-ups

You could watch a video of an octopus changing colour with a child, then play "can you spot where it's hiding?". Letting a child discover that an animal can become part of its background is a captivating insight into camouflage.