Question: What animal has three hearts?
Answer: Octopuses have three hearts. Two of the hearts, called branchial hearts, pump blood through the gills where it is oxygenated. The third heart, known as the systemic heart, then circulates the oxygenated blood throughout the rest of the body. When an octopus swims, the systemic heart temporarily stops beating, which is one reason octopuses often prefer crawling over swimming.
