An earthworm has five pairs of aortic arches, which are often referred to as hearts. This means that an earthworm effectively has ten hearts.
These aortic arches function similarly to hearts in that they help pump blood throughout the earthworm’s body. The blood in an earthworm is not oxygenated in the same way it is in vertebrates; instead, it contains hemoglobin, which helps transport oxygen directly from the soil. This unique circulatory system allows earthworms to thrive in their environment by efficiently moving nutrients and waste throughout their bodies.