Post #953

Octopuses have three hearts and blue blood. Two of their hearts pump blood to the gills, while the third pumps it to the rest of the body. Their blood is blue because it contains a copper-rich protein called hemocyanin, which is more efficient than hemoglobin (found in human blood) at transporting oxygen in cold and low-oxygen environments. This unique circulatory system helps octopuses thrive in the deep sea, where conditions can be quite extreme.