8 Animals With Multiple Hearts

Animals With Multiple Hearts
Photo by Natalia Y. on Unsplash

Did you know there are animals with multiple hearts? Yes, it’s true! Some of the most fascinating creatures in the animal kingdom possess multiple hearts as part of their anatomy.

From starfish to squids, octopuses, and even some species of earthworms, animals with multiple hearts can be found in terrestrial and marine environments.

In this blog post, we’ll explore some unique animals with multiple hearts and learn how they use their multiple-hearted anatomy to their advantage.

1. Octopus

by Ryan Somma is licensed under CC BY-SA 2.0

Octopuses are one of the most fascinating animals with multiple hearts. They have three hearts, which is two more than humans have.

Two of their hearts pump blood to the gills, while the third heart pumps blood throughout the rest of the body. This unique heart structure helps them in a variety of ways. 

For one, it allows them to deliver oxygen to their body and brain more efficiently, allowing them to swim and hunt for longer periods.

It also helps them adjust their blood pressure quickly to accommodate their fast-changing environment, allowing them to squeeze through tight spaces or escape predators.

Interestingly, their hearts also play a role in their mating habits. 

When a male octopus is ready to mate, one of his hearts will stop beating, leading to his eventual death after mating.

Females also experience a change in their heart rate during mating, indicating that their heart is also involved in the process.

All in all, the multiple hearts of an octopus demonstrate how nature has adapted these creatures to thrive in their underwater world.

2. Squid

by wildxplorer is licensed under CC BY 2.0

Squids are fascinating creatures that belong to the same family as octopuses and cuttlefish. They are also one of the animals with multiple hearts.

Squids have three hearts that help them pump blood and oxygen throughout their bodies.  

One of the hearts, called the systemic heart, pumps blood through the body, while the other two, called branchial hearts, pump blood through the gills.

This unique cardiovascular system allows the squid to survive in the deep sea with low oxygen levels.

In addition to their multiple hearts, squid has a remarkable ability to change colors and shapes. 

They use this ability to communicate with each other, camouflage themselves from predators, and attract prey.

Despite their fascinating characteristics, squid faces many threats from human activities, such as overfishing and ocean pollution.

By learning more about these incredible animals with multiple hearts, we can better understand the importance of protecting our oceans and the diverse species that call it home.

3. Earthworms

by schizoform is licensed under CC BY 2.0

Earthworms are fascinating creatures often found in our gardens, helping improve the soil’s quality. But did you know that these slimy creatures have not just one but multiple hearts?

It’s true! Earthworms have five pairs of hearts throughout their body, making them one of the many animals with multiple hearts.

These hearts are responsible for pumping blood and ensuring oxygen is distributed to various body parts.

Unlike humans, who have a centralized circulatory system with a single heart, earthworms have a more decentralized system, with hearts located in different segments of their bodies.

The reason behind this unique adaptation lies in the earthworm’s lifestyle. Earthworms burrow through the soil, and having multiple hearts helps them pump blood efficiently, even when their body is stretched out.

This allows them to move smoothly through their underground tunnels, helping them search for food and aiding in the decomposition process.

Additionally, the multiple hearts of earthworms contribute to their incredible regenerative abilities.

If a part of their body gets damaged or severed, these hearts help pump blood to the injured area, facilitating healing and regrowth.

4. Hagfish

by jonadin93 is licensed under CC BY 2.0

Hagfish are one of the most peculiar animals with multiple hearts. They are slimy, eel-like creatures that can be found at the bottom of the ocean.

They are known for their ability to produce large amounts of slime, which helps them evade predators. However, what makes them truly unique is their cardiovascular system. 

Hagfish have four hearts, which is quite impressive considering their small size. Two of their hearts pump blood to their gills, while the other two pump blood to the rest of their body.

Also, hagfish have a closed circulatory system, meaning their blood remains within their blood vessels. 

The presence of multiple hearts allows hagfish to have a higher oxygen supply, which is necessary for their survival at the depths they inhabit.

It also helps them maintain their blood pressure when they are actively feeding, as they can ingest large prey and need to distribute the nutrients efficiently. 

Overall, the unique cardiovascular system of hagfish is just one of the many fascinating adaptations of animals with multiple hearts. It is a testament to Earth’s incredible diversity and complexity.

5. Cuttlefish

by Cocayhi is licensed under CC BY 2.0

Cuttlefish are another example of animals with multiple hearts. They have three hearts – two branchial hearts that pump blood through the gills and one systemic heart that pumps blood to the rest of the body. 

These fascinating creatures belong to the same family as squids and octopuses, and they are known for their ability to change color and texture to blend in with their surroundings.

They use their incredible camouflage skills to hunt prey and avoid predators.

One interesting fact about cuttlefish hearts is that their branchial hearts stop beating while swimming, allowing them to conserve energy.

When they need to swim more vigorously, their hearts start beating again. Cuttlefish are also unique in how they pump their blood – their hearts do not have valves like ours. 

Instead, they use pressure changes to move blood through their bodies. Cuttlefish are fascinating creatures that showcase the incredible diversity of animals with multiple hearts.

Their ability to change color and texture and unique heart structure make them one of the most intriguing creatures in the ocean.

6. Cockroaches

by darkday. is licensed under CC BY 2.0

One of the most reviled creatures on Earth, cockroaches have evolved a unique physiology to help them survive in almost any environment.

One aspect of this is their multiple hearts. Unlike humans with only one heart, cockroaches have 13 smaller hearts throughout their body, allowing for more efficient circulation and respiration.

In addition to their hearts, cockroaches have a very resilient nervous system and can survive for weeks without food or water.

This has made them notorious pests in human households, where they can quickly multiply and infest a home.

Despite their bad reputation, cockroaches have some fascinating characteristics, including the ability to survive extreme radiation and live for up to a week without their heads.

They also can change color, adapt to their environment, and camouflage themselves from predators.

While many people may not appreciate their presence, cockroaches serve an important ecological role in breaking down organic matter and helping to recycle nutrients.

These animals with multiple hearts may be creepy, but they are impressive.

7. Horse

by David Feltkamp is licensed under CC BY 2.0

While most people may not associate horses with having multiple hearts, these majestic creatures have a unique circulatory system that sets them apart from many other animals.

Horses, along with several other large animals, have what is known as a “double pump” system.

This means that their hearts are not multiple, but they have an enlarged heart that allows for a more efficient blood flow.

In a horse’s circulatory system, the heart consists of four chambers – two atria and two ventricles.

The atria receive blood from the veins and pump it into the ventricles, distributing the oxygen-rich blood to the rest of the body. 

This double pump system ensures that a constant and steady blood flow reaches all areas of the horse’s body, allowing it to perform optimally.

A double pump system is especially advantageous for horses, as they are large, powerful animals that require substantial oxygen and nutrients to fuel their muscles. 

This unique adaptation allows horses to sustain high activity levels for extended periods without tiring easily.

It also enables them to recover quickly from intense physical exertion. While horses may not have multiple hearts, their circulatory system is adapted to meet their specific needs as highly athletic animals. 

The double pump system ensures that they receive a steady supply of oxygen-rich blood to fuel their muscles, making them one of the many fascinating animals with multiple hearts in a different sense.

8. Humans

by hapal is licensed under CC BY-ND 2.0

Despite not being commonly considered animals with multiple hearts, humans have a unique cardiovascular system that allows them to function almost as if they did.

While humans have just one heart, their circulatory system includes pulmonary and systemic circuits.

The pulmonary circuit takes deoxygenated blood from the heart to the lungs to be oxygenated. 

In contrast, the systemic circuit takes oxygenated blood from the heart to the rest of the body.

What sets humans apart is their superior vena cava, which is a large vein that brings deoxygenated blood from the upper half of the body to the heart.

The inferior vena cava brings deoxygenated blood from the lower half of the body. 

This means that humans have two circulatory systems running parallel to each other, which helps ensure that their entire body is supplied with enough oxygenated blood.

Overall, while humans may not have multiple hearts in the traditional sense, their unique cardiovascular system certainly makes them one of the animals with multiple hearts.


In conclusion, the existence of animals with multiple hearts is truly fascinating and shows how diverse and unique life on Earth can be.

While most of us are familiar with humans having a single heart, several other creatures have evolved to have multiple hearts for various reasons.

Earthworms, hagfish, and cuttlefish are just a few examples of animals with multiple hearts that have captured the attention of scientists and researchers. 

Each of these animals has different adaptations that allow them to distribute oxygen and nutrients throughout their bodies effectively.

Interestingly, some animals like cockroaches and horses also possess multiple hearts, although their anatomical structures differ from those of the previously mentioned creatures.

These adaptations serve important functions in these animals’ lives, allowing them to thrive in their respective environments.

Studying animals with multiple hearts provides valuable insights into their biology and physiology and sheds light on the incredible diversity and complexity of life on our planet.

It reminds us that there is still much to learn about the natural world.

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