How many hearts does an octopus have?

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In the oceans we find a vast and wonderful biodiversity about which there is still much to study. Among this fascinating diversity, we find the animals of the order Octopod, that we commonly know as octopuses. These attract attention for their peculiar appearance, in such a way that they have generated various legends and stories about sea monsters, but on the other hand they also generate scientific interest due to various peculiarities that characterize them..

Among the peculiar aspects of octopuses, we find their circulatory system, on which it is said that they have several hearts. But ¿That's right? ¿Do they have several real hearts or just one? If you've ever wondered how many hearts does an octopus have, continue reading this interesting article by AnimalWised, in which we will clarify this question.

You may also be interested: How many brains does an octopus have? Index
  1. How is the circulatory system of octopuses?
  2. So how many hearts do octopuses have?
  3. Why do octopuses have three hearts?

How is the circulatory system of octopuses?

Cephalopods, which is the class to which octopuses belong, are considered the most complex group of invertebrates, since although they have common characteristics with the rest of the mollusks, they have significant differences that place them in a different range. The evolutionary process endowed these animals with particular characteristics that make them a highly competitive group in marine ecosystems.

Despite the presence of a pigment that is not very efficient at using oxygen, thanks to various adaptive strategies they are able to inhabit from the sea floor to areas near the surface. They are also excellent swimmers, they have important defense and attack systems but, in addition, they are very good hunters..

All these advantages could not be developed without the presence of a circulatory system with excellent capabilities. Next, we explain in detail what type of circulatory system octopuses have:

  • Closed circulatory system: the circulatory system of octopuses is closed, that is, the circulating blood remains within the blood vessels.
  • Elastic blood vessels: their blood vessels have elasticity, like that of vertebrates, and are contractile.
  • High blood pressure: heart pulses generate significant blood pressure gradients, which is why these animals have high blood pressure. This is mainly because they have more than one heart..
  • Blue blood: the respiratory pigment in charge of transporting oxygen in the blood is hemocyanin, which is made up of copper and gives the blood of these animals a bluish color. This is dissolved in the blood plasma of octopuses, and not in their cells.
  • Gills with high oxygen uptake: octopuses and cephalopods in general have a low oxygen transport capacity, an aspect that has been resolved with the development of gills with high oxygen uptake and other mechanisms to promote gas exchange.
  • They vary the volume of blood in their gills: they have the ability to vary the volume of blood in their gills, depending on the oxygen requirements at a particular time.
  • Slimy blood: they have viscous blood, since although the water content of the blood is high, so is the solid content.

Now that we know more about the circulatory system of octopuses, let's see how many hearts these animals have and why.

So how many hearts do octopuses have?

Octopuses have 3 hearts, one called systemic or arterial and two branchial. Next, we will explain the differences of each one.

Systemic or arterial heart

This heart is made up of a ventricle, to which the main arteries, and two atria that receive blood from the gills. This heart pumps blood throughout the body and is an optimal organ to distribute the high amounts of blood tissue that these animals require.

Gill hearts

The two gill hearts are smaller in size and act as auxiliary pumps, sending blood to the gills, where the blood oxygenate will occur so that it can later be distributed to the rest of the body, thus oxygenating it completely.

In the following image we can see where the 3 hearts of the octopuses are located.

Image: Pinterest

Why do octopuses have three hearts?

Despite possessing various traits that make them quite advanced animals, octopuses have some unfavorable characteristics for their own species. This has led them to adapt or evolve to optimize their survival in the short life span they usually have (3-5 years, depending on the species). Under these circumstances, the presence of the three hearts in octopuses plays a primary role. On the one hand, the ability to increase or decrease their blood volume helps them especially when hunting their prey or when fleeing from a predator..

On the other hand, octopuses tend to prefer the seabed, which is often lacking in oxygen. However, their gills are highly efficient at absorbing what little oxygen there may be, even exceeding that of fish, allowing them to access prey that other marine animals cannot reach..

To all this, we must add that aquatic animals are under greater pressure than those that inhabit terrestrial ecosystems..

As we have seen, it is thanks to the presence of the three hearts that octopuses have a complex circulatory system, which allows them to have a fairly optimal organism to inhabit the marine ecosystem and survive as a species.

Although octopuses are not the only animals with more than one heart, they attract attention for their peculiar anatomy, but also because scientific studies increasingly show greater singularities of these animals, among which is their outstanding intelligence.

¿Did you know that octopuses are also said to have 3 hearts and 9 brains? But ¿That's right? In this other AnimalWised article, we explain ¿How many brains does an octopus have??

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