3 Remarkable Animals That Possess Multiple Hearts

The concept of a single heart is deeply rooted in our understanding of biology. While most organisms, including humans, are equipped with one cardiac organ, certain species defy this norm. Discover a few extraordinary animals that boast more than one heart.

1. Octopus and Squid

Both octopuses and squids, belonging to the cephalopod family, possess three hearts. One central heart circulates blood systemically, while the other two, known as 'gill hearts,' pump blood to the gills.

2. Earthworms

Although not a true heart, the aortic arch in earthworms serves a comparable purpose and is often called a heart for simplicity. Earthworms have five of these arches, functioning as hearts, which are segmented and circulate blood throughout their bodies.

3. Hagfish

This peculiar creature surprises with its four hearts: a primary three-chambered systemic heart and three additional accessory pumps.

Bonus: Humans

Interestingly, some humans possess more than one heart, particularly those who have undergone a 'piggyback' heart transplant. This procedure involves adding a supplementary heart rather than replacing the original. The native heart continues to function at a reduced capacity, while the transplanted heart handles the majority of the workload. In one case, a patient who received the transplant as an infant later had the additional heart removed, and her original heart successfully resumed full function.