FactSentinel

Octopuses do indeed possess three hearts, a remarkable anatomical feature that supports their unique circulatory system. Two of these hearts, called branchial hearts, are located near the gills and pump deoxygenated blood to the respiratory organs where it receives oxygen. The third heart, known as the systemic heart, then pumps the newly oxygenated blood throughout the rest of the body to supply the octopus's organs and tissues. This three-heart system is well-documented in marine biology and has been observed across all octopus species.

This unusual cardiovascular arrangement exists because octopuses have blue, copper-based blood (hemocyanin) rather than the red, iron-based blood (hemoglobin) found in mammals. Hemocyanin is less efficient at transporting oxygen, particularly in cold ocean environments, so the additional hearts help compensate by maintaining adequate blood pressure and circulation throughout the octopus's body. Interestingly, when an octopus swims, the systemic heart stops beating, which is why these creatures prefer to crawl along the ocean floor rather than swim, as swimming exhausts them quickly.

A common point of confusion involves whether all cephalopods share this trait. While octopuses, squid, and cuttlefish all have three hearts, not all marine creatures possess multiple hearts. This feature is specific to cephalopods and represents an evolutionary adaptation to their active, predatory lifestyle and the challenges of oxygen transport in marine environments.