The blue whale is the largest animal. It also has the largest heart. A blue whale’s heart weighs about 400 pounds. That’s how much a large refrigerator weighs!
The smallest heart belongs to a tiny wasp (a small insect that can fly). The heart runs along its back. It is so small, you need a microscope (a machine that makes small things look bigger) to see it!
Photo Credit: Ajit S N/Shutterstock
