Octopuses have three hearts: two pump blood to the gills and one pumps oxygenated blood to the rest of the body.

Octopuses have a special circulatory system with three hearts. Two of these hearts are called branchial hearts, and their job is to send blood to the gills. The gills are where the blood picks up oxygen from the water. Then, the third heart, called the systemic heart, pumps this oxygen-rich blood to the rest of the octopus’s body. This division of labor helps the octopus get enough oxygen to its muscles and organs, supporting its active lifestyle underwater.