How many hearts does an octopus have and why?

An octopus typically has three hearts. Two of these hearts are referred to as branchial hearts, and the third is called the systemic heart.

The two branchial hearts are responsible for pumping blood through the gills, where oxygen is extracted from water and carbon dioxide is released. This oxygenated blood is then pumped to the systemic heart. The systemic heart, in turn, distributes the oxygenated blood to the rest of the octopus's body.

The reason for having three hearts is linked to the unique respiratory and circulatory system of octopuses. Unlike vertebrates, including humans, who have a centralized circulatory system with a single heart, octopuses have a more distributed system that involves multiple hearts. This adaptation helps improve the efficiency of oxygen transport in their aquatic environment, where obtaining oxygen from water is crucial for survival.

The decentralized cardiovascular system of octopuses allows for a more direct and efficient flow of oxygenated blood to their tissues, enhancing their ability to extract oxygen from water and maintain an active and agile lifestyle.