Animals with Two or More Hearts
Rarely do animals need multiple hearts. Multi-heart animals are rare. Nature has helped these animals live with two or more hearts.
Squids have three hearts despite their many varieties and sizes. Small squid are present in every ocean. Few became huge and live in deep, dark water.
Octopuses have several hearts and are well-known. Hundreds of octopus species have three hearts: one for their circulatory system and two for their gills.
Earthworms have more than one heart. As long as there's soil, decomposers are everywhere. Earthworms have five simple hearts.
Four-heart hagfish. One heart is the major circulatory organ, while the others pump blood. Hagfish live in the Atlantic and Pacific oceans and have few predators.
Cuttlefish is related to octopus and squid, which also have many hearts. The cuttlefish has three hearts, one for the body and two for the gills.
Their ability to tolerate high temperatures and injuries is well-known, and they have 13 hearts. Their heartless structure makes them tough.
Each foot has a frog-shaped organ. The frog's heart is a blood store. When a foot touches the ground, frog blood is pumped into the horses' arteries.