How does heart size relate to the size of an animal?

Question

Chloe Adams · Accepted Answer

Generally the larger the animal, the larger the heart.

Big animals, such as whales, have large chest cavities that can support large hearts. These animals also require large hearts because they have many cells that require blood flow. Humans, on the other hand, are neither too big nor too small, with a heart that is about the size of a grown man's fist. Because we don't have large bodies, we don't need large hearts; having a heart that reflects this allows our chest to support other organs, such as the lungs. An intriguing side note is that an animal's heart beats faster in smaller sizes and slower in larger ones. The heartbeat of a blue whale, for instance, is approximately 9–10 beats per minute, whereas the heartbeat of an Etruscan tree shew, an animal so small it can fit in the palm of your hand, is known to exceed 1000 beats per minute.

Austin Alexander · Answer

undefined The size of an animal's heart is generally proportional to its body size. Larger animals tend to have larger hearts relative to their body size, while smaller animals have smaller hearts. This is because the heart needs to pump blood to all parts of the body, and larger animals require more blood flow to supply oxygen and nutrients to their tissues.