Jellyfish are animals belonging to the Cnidaria phylum and are found in almost all marine environments. Like the rest of the living beings, they need to eat to get all the necessary nutrients to survive. Their diet is quite varied, but, in general, it can be said that jellyfish are carnivorous Their body is adapted, through their tentacles, to capture prey, consume it and digest it slowly. Some species are even capable of capturing large fish, and this happens thanks to the cnidocytes, stinging cells located in the tentacles and through which they can defend themselves against predators or capture their prey, in many cases they can even paralyze them.
Do you want to know what jellyfish eat? Continue reading this article on our site and you will know all the details about jellyfish feeding.
Jellyfish feeding
Have you ever wondered what sea and freshwater jellyfish eat? Well, the food they consume varies according to the species, but as we mentioned, they are considered primarily carnivorous animals, being strong competitors thanks to their high predation rates, since the larger species are capable of catching large fish. In general, they rely on the wind and sea currents to find their food and, once it finds it, it catches it with its tentacles, provided with a powerful toxin, and then it is taken to its mouth.
In the case of larger jellyfish, as they are able to swim vertically, they can consume crustaceans, small fish and even other species of jellyfishsmaller, so it could also be said that they are opportunistic animals, since they consume almost any prey that falls into their tentacles.
As a general rule, regardless of the size of the jellyfish, its main food is plankton, since, being microorganisms floating, jellyfish simply by moving their tentacles in the water can catch plankton. And, as we mentioned before, the size of other prey will depend on the size of the jellyfish, since the larger the jellyfish, the chances of catching a larger prey increase. They are also capable of breaking down the hard shells of some molluscs, although this task takes longer.
So what do jellyfish eat? Mainly plankton and, depending on their size or type of jellyfish, other animals smaller than them. And as a curious fact, who eats jellyfish? Jellyfish predators vary depending on where they are found, but mainly sea turtles, sunfish, some sharks and some whales have been recorded.
What do jellyfish eat before they become adults?
During the larva, polyp, and ephyra stages, jellyfish feed on plankton. Thus, it is not until they reach adulthood that they become opportunistic animals and begin to feed on fish or crustaceans.
How do jellyfish hunt?
Now that you know what aquatic jellyfish eat, how exactly do they eat? These animals are able to find their prey thanks to sensory receptors that they have in the bell (that is, the upper part of the body known as the umbella) and their tentacles.
Almost all species of jellyfish activate their tentacles and their toxin when they come into contact with their food and, as they do not differentiate between humans or potential prey, accidents with these animals are very common. When they locate potential prey and grab it with their tentacles, they discharge toxins through specialized cells that, like stingers, can release the venom, thus they are able to paralyze their victim. Once this is done, they slowly carry it to their mouths by means of their tentacles. Jellyfish have a gastrovascular entrance, next to the mouth, and this is where they digest food thanks to the action of digestive enzymes.
As we said, they are opportunistic animals, being able to consume a large number of prey, simply by swimming or being carried away by sea currents. In addition, there are hunting techniques that jellyfish use. To do this, they always use their tentacles, which are fine threads that surround their mouth and that in some species can be incredibly long, reaching up to 50 meters in length, although other species can have them very short, but all with the characteristic stinging cells.
Among the hunting mechanisms, we can name two main ones: cruise behavior and ambush behavior. These techniques make them powerful competitors within food webs, to such an extent that they can even considerably affect the organisms of an ecosystem. Let's see what each method consists of below:
- Cruising behavior: it is typical of jellyfish of the order Rhizostomea, where the capture of their prey is carried out by means of filtration. Through movements of the umbella and thanks to the marine currents, the prey are directed towards the oral arms (which are shorter tentacles that surround the oral cavity) and the mouth, where they are trapped by the cnidocytes, that is, the cells stinging.
- Ambush behavior: Used by jellyfish that have stronger, longer tentacles and are opportunistic predators, usually species of larger size. This technique is based on swimming in a zig-zag and in this way being able to group the prey and then catch them with rapid movements.
In the following video shared by Sabrina Inderbitzi we can see a jellyfish hunting.
How do jellyfish digest?
Although their body is very primitive and they do not have all the organs present in other animal groups, jellyfish are capable of carrying out vital processes such as digesting their food. These striking animals are endowed with a single cavity, which is the mouth, and next to it is the gastrovascular cavity Digestion occurs inside this cavity, which is provided with ciliated cells and digestive enzymes, through which digestion is carried out once the food comes into contact with the walls of the gastrovascular cavity. In addition, this cavity functions as a system to distribute all nutrients, oxygen and as an excretory system, since jellyfish do not have a well-differentiated digestive and excretory system.
The gastrovascular cavity is separated from the outside only by the mouth, which is where waste will also be eliminated, so this opening functions as a mouth and anus. Subsequently, the distribution of all the nutrients is in charge of fine tubes called radial canals, which carry all the nutrients to the rest of the body.
Did you know all this about how jellyfish digest? Now that you know what jellyfish eat, how they hunt and how they digest their prey, don't miss these other articles to continue expanding your knowledge:
- How do jellyfish reproduce?
- How are jellyfish born?
