The 400-pound heart of a 40,000-pound animal is still pretty big! Though the heart is only about 1% of the whale’s body weight, it’s still the biggest on the planet. What about the heart of the world’s largest terrestrial creature? How big is your own heart? How does it compare to the size of a blue whale’s heart? Let's see. African elephants are the largest terrestrial creatures on Earth. Their round-shaped hearts weigh about 30 pounds. A blue whale’s heart weighs about 14 times as much as an elephant’s heart and it makes up about 5% of an elephant’s weight. Yes, you can say No Way! A blue whale’s heart weighs about 640 times as much as a human heart. Tales of its heart being as big as a car, with the aorta (its main artery) large enough for a human to swim through abound, but as finding intact specimens to research is rare, the truth has been difficult to find out.