Beastfile · Marine Life

Octopus

Octopus vulgaris

Also known as Common Octopus

Three hearts, blue blood, and most of its neurons outside its head.

On This Page▾

Overview

An octopus runs on a body plan assembled on a completely different branch from ours. Three hearts: two pump blood through the gills, one pumps it to the body, and that third one stops whenever the animal swims, which is part of why octopuses would rather walk. The blood is blue because it carries oxygen on copper-based hemocyanin rather than iron. Around two thirds of its neurons sit in the arms rather than the brain, so an arm can solve a good deal of a problem on its own. It has no bones at all, so anything its beak fits through, it fits through.

An octopus showing its suckered arms and horizontal pupil

Origin

Temperate and tropical seas worldwide, in rocky reef, seagrass and rubble in shallow coastal water, denning in crevices.

Habitat

Ocean

Notable Traits

•Three hearts, one of which stops while swimming
•Blue, copper-based blood
•Two thirds of its neurons are in its arms
•No bones, so it fits through any gap its beak clears
•Changes color and skin texture in under a second

Conservation

Least Concern, and heavily fished. The species is widespread and fast-growing, which buffers it, but octopus fisheries are expanding quickly and are largely unmanaged.