Do Any Animals Not Have A Heart?

By Antonia Čirjak on June 16 2020 in Did You Know

The jellyfish is probably the most well-known out of all the animals without a heart.
The jellyfish is probably the most well-known out of all the animals without a heart.
  • The jellyfish is probably the most well-known out of all the animals without a heart but also without a brain.
  • Flatworms are also without a heart and they use a special process to receive oxygen and nutrients and transport them through the body.
  • Other animals without a heart include sponges, starfish, sea anemones, sea cucumbers, and sea lilies.

The importance of the heart for our lives is something that can’t be stressed enough. Simply put, living without a functioning heart is not possible; it is what keeps our blood flowing and keeps us alive. Of course, there is also the symbolic value we often add to the heart, making it an essential aspect of love, for example.

These reasons, along with many others, are why it is so hard to imagine life without a heart being possible. However, some animals manage to survive just fine without one. They do not need a heart for the constant flow of oxygen and nutrients. These animals include the jellyfish, flatworms, corals, polyps, starfish, sponges, and several others.

The Spooky Jellyfish

The jellyfish is probably the most well-known out of all the animals without a heart. We should also mention that it doesn’t even have a brain. Naturally, it is not hard to conclude that there is no blood flowing through the body of a jellyfish. One look at it and everything is clear - see what we did there? This is why the heart is unnecessary. It would serve no purpose. The jellyfish just flows through the oceans without consciousness. It just exists, flowing endlessly. 

One look at it and everything is clear (see what we did there?).
One look at it and everything is clear - see what we did there?

The jellyfish is the biggest animal that has no hearts. It can grow up to 8 feet in length, but if we include its tentacles, it goes up to over 50 feet. That can be a scary thing to imagine, a giant jellyfish, just floating the oceans unconsciously, without a heart. It’s the stuff of nightmares! They still need to feed, and they will eat almost anything they stumble upon, from plankton to small fishes.

Another interesting thing about the jellyfish is that it can regenerate its body. They do not have a maximum lifespan; they might be able to live forever. If you are wondering why there are no horror films made about these animals, join the club because we are as well. They are scary!

Other Heartless Animals

Among other animals that do not have hearts, corals are also extremely interesting.
Among other animals that do not have hearts, corals are also extremely interesting.

Flatworms are another type of animal that has no heart. Their bodies are just so flat that there is simply no place for one. They use a special process to receive oxygen and nutrients and transport them through the body. This process is called diffusion, and it makes the oxygen simply flow through the body while the flatworm is moving without a pump or pressure. Just like the jellyfish, flatworms can regenerate, which leads us to believe that maybe not having a heart is the key to eternal life?

Among other animals that do not have hearts, corals are also extremely interesting. Many might not even consider them animals, but they most certainly are. Both corals and polyps survive on zooplankton and by using photosynthesis performed by small plants that live on top of them. They do not have blood or vessels.

More sea creatures manage to survive without a heart, but these animals do not have any organs either. The list includes sponges, starfish, sea anemones, sea cucumbers, and sea lilies. 

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