Why Do Octopuses Have Three Hearts?

Octopuses belong to the group of mollusks that live in the sea and have highly distinctive body structures. They possess many unique characteristics, one of which is having three hearts. Why do they have three hearts? What is the function of each?

How Many Hearts Do They Have?

Octopuses have three hearts.

- Two function as "branchial hearts".

- One serves as the "systemic heart".

Image showing the octopus hearts (generated by artificial intelligence).

What Do the Branchial Hearts Do?

The branchial hearts pump deoxygenated blood to the gills, where the blood is cleaned and enriched with oxygen.

These two hearts are responsible solely for respiration.

What Is the Role of the Systemic Heart?

The systemic heart pumps the oxygenated blood throughout the body, providing energy to all parts of the octopus.

In other words, the systemic heart supports movement and vital functions.

What Happens When They Swim?

When an octopus swims, its systemic heart temporarily stops. This makes swimming more difficult. For this reason, octopuses typically move by crawling.

Children examining an octopus (generated by artificial intelligence).

Why Is Their Blood Blue?

Octopus blood is blue because, instead of hemoglobin found in humans, their blood contains hemocyanin.

- Hemocyanin carries oxygen.

- The copper in its composition gives the blood its blue color.

What Is the Purpose of Blue Blood?

- Blue blood enables octopuses to survive in deep-sea environments with low oxygen levels.

- This trait makes them resilient to harsh environmental conditions.

How Does It Fit Their Body Structure?

- Octopuses have eight arms and a highly developed brain.

- This anatomy requires constant activity of numerous muscles and nerves.

- Therefore, the three hearts ensure rapid oxygen distribution throughout the body.

- In other words, their circulatory system is adapted to their complex body structure.