Yes, an Octopus Really Does Have 3 Hearts

An octopus has 3 hearts — and the main one stops beating when it swims.

Octopus blood is blue because it uses copper instead of iron to carry oxygen.

They have 9 brains — one central brain and a mini-brain in each of its 8 arms.

Octopuses are colorblind, yet they can perfectly match any color for camouflage.

The giant Pacific octopus can grow to over 4 meters in arm span and weigh 50 kg.

Octopuses can open a screw-top jar from the inside — a classic intelligence test.

Octopuses may dream — scientists observed rapid color changes during their sleep.

Most octopuses live only 1–2 years — then die shortly after mating.

Octopus ink contains tyrosinase — a chemical that blinds predators' sense of smell.

Each octopus arm has suckers that can taste what they touch — independently.