Do you know much about octopuses? Besides having eight legs? For example, do you know how many hearts an octopus has? Yes, the question is asked absolutely right. After all, the octopus has not one heart, but several! Or what are these creatures capable of?
Let's figure it out. And not only in how many hearts the octopus has, but in general, what kind of animal it is, where it can be found.
Huge clam
Octopus (photo below) refers to cephalopods. These creatures live in the vast expanses of the globe, from the Arctic to the Antarctic. But still, octopuses cannot tolerate fresh water, give them a salinity of at least 30 percent.
Their sizes are also very different: from a few centimeters to 6-7 meters. But still the “average height” for them is 1.5-2 meters. The biggest octopuses live off the coast of Colombia: some weigh 15-20 kg each, and the length of their tentacles varies from 2 to 2.5 meters, and sometimes even more!
The largest octopus was discovered in Western Canada. This octopus giant weighed 242 kilograms, and the length of its tentacles reached 10 meters! A terrible sight, probably. Now all the stories of sailors about the Kraken, capable of sinking the ship, no longer seem just silly fairy tales.
The external structure of the octopus
Octopuses have a soft oval body dressed in a mantle (skin-muscle bag). The mantle can be smooth, with pimples or wrinkled (depending on the type of octopus). Inside, under it, are the organs.
The mantle also serves as a repository of water. Since the octopus is a sea creature, it cannot exist without water. In order to get out on land, he needs a supply of liquid. This reserve is enough for four hours. However, cases have been recorded when octopuses remained on land for more than a day.
On the head of the octopus are large eyes, like most representatives of deep-sea creatures, with square-shaped pupils.
The octopus has a small mouth with a pair of strong jaws. Outwardly, it resembles a beak of a parrot. Therefore, it is called - "beak". There is a lingual outgrowth (“odontophore”) in the mouth. On both sides of the body are the gills, which are responsible for the extraction of oxygen from the water.
Tentacle arms
Eight tentacle arms surrounding the mouth extend from the head. On the inside of each tentacle are suction cups, with which the octopus is able to hold prey or stick to underwater objects. On one "arm" of the suction cup can be up to 220! An interesting fact is that there are visual analyzers in the suction cups . So the octopuses are truly unique: able to see with their limbs!
The tentacles of the octopus most often become the object of attack by enemies. Therefore, nature has endowed octopus with the ability to tear off its limbs in order to escape. The enemy will only have a trophy. Such a property in science is called autotomy. The muscles of the tentacles begin to contract so much that it leads to rupture. Literally a day later, the wound begins to heal, and the limb regrowth. You will say, like a lizard. But no. A lizard is able to cast its tail only in a certain place, no more, no less. And the octopus can tear off its "hand" wherever it wants.
The internal structure of the octopus
Octopus has a huge brain that protects the cartilaginous capsule (skull). The brain consists of 64 lobes and even has the rudiments of the cortex. Biologists compare the intelligence of an octopus with the mind of a domestic cat. Octopuses are capable of emotions and are very smart. They have a good memory and are even able to distinguish geometric shapes.
Like other creatures, octopuses have a liver, stomach, glands, and intestinal tract. So, the esophagus enters the liver and brain along the way to the stomach. The esophagus is very thin, therefore, before swallowing food, a good octopus crushes it with a “beak”. Then, already in the stomach, digests food with the help of digestive juice, which is produced by the liver and pancreas. In the stomach, the octopus has a process - the tsekum, which is responsible for the absorption of nutrients. The octopus liver is a large brown oval-shaped organ. It performs several functions at once: it absorbs amino acids, produces enzymes and stores nutrients.
In the occipital part of the skull are the balance organs - statocysts. These are bubbles inside which there is a liquid and calcareous stones (statoliths). When the body of the octopus changes position in space, the pebbles move and come into contact with the walls of the vesicles covered with sensitive cells, which irritates the octopus. In this way, he can navigate in space even without light.
In a special process of the rectum, the octopus stores a stock of poisonous ink, which serves as an excellent means of protection. The skin (or rather, the octopus mantle) contains specific cells: chromotophores and iridiocysts, which are responsible for the ability to change color. The first ones contain black, red, brown, yellow and orange pigments. The second allows the octopus to become purple, green, blue or metallic.
Octopuses have a highly developed circulatory system. Muscles and skin in many places have capillaries, which serve to transfer arteries to veins.
How many hearts does an octopus have
So, we come to this question that is of concern to many. It is already clear that these creatures have more than one heart. But then how much? Probably, everyone will be surprised now. After all, the octopus has 3 hearts. As many as three! None of the representatives of mammals, amphibians or birds have such a phenomenon. Yes, there are four-chamber hearts, like mammals, three-chamber ones, like amphibians, or even single-chamber (fish) hearts. But one heart for each!
Then why does the octopus have 3 hearts? Recall that the heart is a muscle that, contracting at a certain speed, pumps blood in a living organism. So, cephalopods, which include the octopus, have not too “successful” gills: they create strong resistance to blood. Therefore, one heart simply could not cope with it.
How do they work?
So, the octopus has three hearts. One is the main thing that drives blood throughout the body of an octopus. This heart consists of two atria and a small ventricle. And one more heart near each gill (the octopus has two of them). These hearts are smaller. They help the main muscle to push blood through the gills, from where it, already filled with oxygen, returns to the atrium of the big heart. Therefore, they are called "gill".
No matter how many hearts the octopus has, they all beat the same. The frequency of their contractions depends on the temperature of the water in which the creature is located. So, the colder the water, the slower the beat of the heart. For example, at a temperature of 20-22 degrees, muscles contract somewhere 40-50 times per minute.
Incidentally, the heart of an octopus, or rather the heart, is far from the only feature of the mollusk. His blood is also very peculiar. She imagine blue! The thing is that it contains the hemocyanin enzyme, which contains copper oxides.