15. Insect Hearts: Tubes Not Pumps
Unlike the powerful, multi-chambered hearts of mammals, insects possess a simple, tube-shaped heart that runs along their back.
This dorsal vessel contracts to push blood—actually called hemolymph—through their bodies.
Instead of a closed circulatory system, insects have open circulation, where hemolymph bathes organs directly.
This unique adaptation is perfectly suited to their small size and lightweight bodies, helping them stay active and efficient.