Octopus hearts solve the circulation problem a bit differently. They have one main heart, called the systemic heart, and two smaller hearts located near their gills. The two smaller hearts perform the same task as the right side of the human heart. They pump blood to the gills where it dumps waste and loads up on oxygen, then pump the oxygen-rich blood back to the main heart. The main heart then pumps the refreshed blood through the octopus's body.