With their sinuous, translucent bodies and unexpected colors, jellyfish are some of the most mysterious creatures in the ocean. Their way of living and reproducing has unique processes that never cease to amaze the scientific community and could revolutionize medicine in the future.
In this article on our site, we discover funny facts about jellyfish and reveal some of their most striking features. Delve into the fascinating world of this animal.
They have been around for millions of years
Jellyfish have been on Earth for millions of years; more specifically, 600 million years, according to the Ministry for the Ecological Transition and the Demographic Challenge of the Government of Spain. The first fossils attributable to jellyfish date from neither more nor less than the Primary Era. Today, the common jellyfish or moon jellyfish continues to arouse much curiosity among marine biologists.
Made mainly of water
Jellyfish are animals belonging to the Cnidarian family. As we know, their morphology is bell-shaped, thanks to which they are able to move through the water with their characteristic rhythmic contractions. Thanks to their anatomy, made up of 95% water, jellyfish have a series of attributes (luminescence, ability to cause hives, etc.) that make them into curious and fascinating beings.
The mouth also functions as an anus
Jellyfish are carnivorous animals and, as such, have a digestive system that allows them to assimilate and metabolize their prey. Jellyfish, although they may not seem like it, do have a mouth, but in a slightly unexpected place: their mouth is located in the lower part of their anatomy and serves both to ingest food and to excrete faeces. The mouth also empties directly into what is called the "gastrovascular cavity", that is, the space in which digestion takes place. This is one of the lesser-known curiosities of jellyfish.
Your body is full of light
The bioluminescence, or the ability of some living organisms to produce light, is another fun fact about jellyfish that you may have seen in aquariums or on a beach at night. These animals transform chemical energy into light energy to defend themselves against predators, attract prey or court potential mates [1]
In the case of jellyfish, this reaction can occur in symbiosis with a certain type of bacteria or extracellularly.
They have neither brain nor blood
Another curious thing about jellyfish that never hurts to know is that these animals do not have a brain as such. His body could be described, plain and simple, as a sort of mobile water sack. As we mentioned before, jellyfish are made up of 95% water and their body is made of a series of tissues that are very different from those of humans.
According to Dr. Lucas Brotz, from British Columbia University and a well-known researcher on the Cnidarian family, the anatomy of jellyfish is made up of two layers of thin cellular tissue, between which an inert and aqueous material is located. His research indicates that the size of jellyfish, as well as the variation experienced by their population, is directly related to the impact of human beings on the coasts and the marine environment [2]This fact is not negligible: for 600 million years, jellyfish have survived various mass extinctions. Discovering the secret of its adaptability will allow us to foresee future environmental catastrophes.
They sting until after they die
Have you ever stepped on a jellyfish body washed up on the beach? It is not easy to distinguish them: their transparent and sticky bodies end up buried in the sand, which makes them a risk for vacationers who walk along the shore. If you've ever accidentally stepped on one, you know that the tentacles of a dead jellyfish still cause hives, albeit to a lesser extent.
The stinging cells that jellyfish in particular and cnidarians in general have are calledcnidocysts Upon contact with a possible prey, they use a series of filaments equipped with spines to inoculate the poison. Changes in temperature often reactivate these cells, so if you are stung by a jellyfish, rinse the wound with room temperature s alt water.
They have several types of playback
Another of the curiosities of jellyfish is that they do not have a single form of reproduction. These animals are characterized by having what is known as alternating generations, which consists of presenting, on the one hand, asexual reproduction through sessile polyps and, on the other hand,, sexual reproduction through free-living jellyfish.
Jellyfish are oviparous and lay hundreds of eggs, which are hatched between the tentacles of the parent. When they hatch, larvae known as papules are born, which will look for a suitable place to adhere and become a polyp. From here, depending on the type of jellyfish, the development of these animals will vary enormously. Discover How jellyfish are born in this other article.
Among them is one of the most feared animals
The sea wasp (Chironex fleckeri) is considered the most poisonous jellyfishof all, and one of the most dangerous animals in the world [3] It lives in Australia and its venom is created to quickly paralyze its prey, so it causes serious damage that ends up being fatal, even for human beings. This is so because its venom includes hundreds of toxins.
There is a kind of giant size
The giant lion's mane jellyfish (Cyanea capillata) is recognized worldwide for being the largest jellyfish in the world, this being another of the curious facts of the most surprising jellyfish. The body of this species can reach almost 4 meters in diameter and its tentacles almost 40 meters long In short, this is an imposing animal and, without a place Undoubtedly, incredible.
The smallest jellyfish is one of the most poisonous
Known as irukandji jellyfish (Carukia barnesi), it has a body that measures approximately 35 mm in diameter and tentacles that barely reach 1.2 cm in length [4] For this reason, it is considered the smallest jellyfish in the world. However, despite its small size, it is known for being the second most poisonous jellyfish in the world, even being deadly if not treated in time.
