Cnidarians correspond to a group of aquatic animals and, although some inhabit freshwater ecosystems, they are mainly marine. Within this group we find the jellyfish, who are grouped in the subphylum Medusozoa (also considered a clade) and correspond to different taxonomic classes. Jellyfish are very peculiar animals due to their particular gelatinous, transparent and sometimes colored bodies. In general, they all have toxins that they use to trap their prey, but some species in particular are very dangerous and even deadly to humans.
Now, precisely because of their physical characteristics, many people wonder how these animals move, do they swim? Therefore, in this article on our site we will explain how jellyfish move, keep reading!
Do jellyfish swim or float?
Jellyfish are exclusively aquatic animals, so they require a body system adapted to live in water. The body of jellyfish is made up of more than 90% water and protein, having a peculiar umbrella or bell shape. This "bell" is known as the umbrella and is made up of the following parts, among others:
- Exumbrela: corresponds to the aboral region or area opposite the mouth and is located on the surface of the animal. Various tentacles are connected to the exumbrela, in which the characteristic stinging or poisonous cells of the group are found.
- Subumbrela: it has a concave shape and is the oral part, located below the jellyfish when viewed from above.
Jellyfish, as we have mentioned, have a gelatinous body that makes it easier for them to be in the water and has a generally fragile appearance, since even in some species it is translucent, although in some cases the tissue is more complex.
All these features mentioned are closely related to the movement of jellyfish in the water, since, on the one hand, They can float freely and be carried away by currents , however, They also have the ability to swim In fact, they are excellent swimmers and can even swim against the current if they so choose.
Jellyfish are predators that feed on other animals, which they seek out and can capture with their tentacles and inject them with the paralyzing toxins they possess. In this sense, despite their fragile appearance, are very active animals in the water, with a great capacity for voluntary movement according to their needs. Do not miss this other article if you want to discover what jellyfish eat.
How do jellyfish move?
Despite their relative lower complexity, compared to other groups of animals, jellyfish are active individuals and predators in the water. With the passage of time and research, it has been reported [1] that, in addition, are very efficient swimmers, in fact, much more than other species, and this is due to the way in which they use energy to move, which in their particular case corresponds to a lower energy consumption, specifically, 48% below of the rest of the swimming animals.
Studies have been carried out particularly with the moon or common jellyfish (Aurelia aurita), in which it was possible to verify that it manages to create pressure differences around it, which generates a kind of suction that pushes and helps with swimming mobility. This is possible because when the jellyfish contracts the umbrella, increases the internal pressure and lowers the external one, and physics tells us that objects move from high to low pressures, which generates momentum in the animal
But the study carried out, in addition, refers that these peculiar animals are capable of using another way to swim, and that is that their body is made up of muscle fibers that, although they are primitive cells within animals, help motor function. The movements that the jellyfish makes with its umbrella move the water inside and also provide an impetus for swimming.
Finally, we can mention in relation to how jellyfish move that they can swim against the current and manage to do it both vertically and vertically. This is the case of the sea nettle (Chrysaora quinquecirrha), as well as horizontally, even near the surface, such as the moon jellyfish (Aurelia aurita).
Having said all of the above, we see that jellyfish do not move with their tentacles, but with their umbrella.
Why do jellyfish move?
For some time it was thought that jellyfish were animals exposed to the mercy of water currents, but we now know that this is not the case. It is now known that these animals move for different reasons. On the one hand, habitat conditions can influence in their displacement, factors such as dissolved oxygen in the water, salinity or temperatures are conditioning factors for them to remain in areas individuals or mobilize. On the other hand, food availability is also an aspect that influences their mobilization.
Currently, there is a lack of studies to delve into the reasons why jellyfish move in the sea, however, it has been possible to identify that they move in a targeted and organized mannertowards certain specific places, even forming colonies made up of thousands of individuals, which may eventually affect activities such as tourism in coastal areas.
Among the aspects that scientists estimate that jellyfish can use to detect the direction of currents and orient themselves in the water, are their own body or some specific signals such as infrasound or the magnetic field of the the earth. These aspects are very interesting, since they are animals that lack an advanced visual system, but have an efficient sense of orientation
Now that you know how jellyfish move, do you want to continue discovering amazing facts about them? If so, we encourage you to consult this other article with the most incredible curiosities of jellyfish.
