Blue whale has the largest heart on Earth 
According to the Guinness World Records, blue whale has the largest heart among all living creatures. A whale's aorta (body's main artery) is large enough for an adult to crawl through and it pumps approximately 15,000 pints of blood as compared to 8 pints in a human. Additionally, the blue whale's heart beats only 5-6 times per minute on surface.