How many hearts does an octopus

Solution

Octopuses have three hearts, which is partially related to their blue blood. Two peripheral hearts pump blood through the gills to collect oxygen, then a central heart circulates this oxygenated blood throughout the body to provide energy to organs and muscles. Additionally, octopuses have 9 'brains' - one central brain for overall control plus eight smaller ones. For comparison:
- Birds and mammals: 4-chambered hearts (two atria and two ventricles)
- Amphibians like frogs: 3-chambered hearts (one ventricle and two atria)
- Fish: 2-chambered hearts (one atrium and one ventricle)