Why Octopuses Have Three Hearts and Blue Blood

Why Octopuses Have Three Hearts and Blue Blood

Octopuses are among the most alien-like creatures on Earth.

Three Hearts

One systemic heart pumps oxygenated blood to organs. Two branchial hearts pump blood through the gills. The systemic heart stops beating when swimming, which is why octopuses prefer crawling.

Blue Blood

Octopus blood uses hemocyanin (copper-based, blue) instead of hemoglobin (iron-based, red). Hemocyanin carries oxygen dissolved in blood plasma. Less efficient but works better in cold, low-oxygen deep-sea environments.

Other Alien Features

Nine brains: one central brain plus eight mini-brains at the base of each arm. Arms act independently. Camouflage via chromatophores changing color in 0.3 seconds. No bones except beak (can squeeze through any gap larger than beak). All octopuses are venomous; blue-ringed octopus contains tetrodotoxin.

Intelligence

Can solve mazes, open jars, use tools, recognize faces, and learn by observation. Have demonstrated play behavior.

Lifespan

Most species live 1-2 years only. Females die after egg laying. Their intelligence evolved completely independently from vertebrates.