Jellyfish have stinging tentacles to defend themselves and capture their prey. The stinging cells present on the tentacles contain toxins that paralyze the prey or deter predators.
Jellyfish have tentacles filled with thousands of tiny cells called cnidocytes. In each cnidocyte, there are kinds of tiny venomous harpoons, nematocysts, ready to be fired as soon as they are touched. At the slightest contact, a signal triggers the immediate firing of the harpoon, which pierces the skin of the prey or predator and promptly injects venom. This quick and reflexive mechanism allows jellyfish to easily capture their food or defend themselves. The potency of the venom varies from species to species; some jellyfish are merely annoying, while others are downright dangerous.
The stinging tentacles are the true hunting advantage of jellyfish. Thanks to specialized cells called cnidocytes, they sting or paralyze their prey in a matter of seconds. As soon as a prey touches these tentacles, tiny venomous harpoons called nematocysts are triggered and inject their devastating toxin. The result: the prey is almost immediately neutralized, and then the tentacles gently bring it to the mouth of the jellyfish. Efficiency and simplicity: the jellyfish can then effortlessly devour plankton, small fish, or crustaceans, thus ensuring its survival peacefully.
Evolution is rather cunning: it equipped jellyfish with cnidocytes, which are essentially their weapon cells. These specialized cells stem from a long series of evolutionary adaptations, refined over millions of years. A better-armed jellyfish had a higher chance of catching its prey and surviving predators, allowing it to reproduce more and pass on this useful trait to its descendants. Little by little, the stinging characteristic was amplified through natural selection favoring the most effective jellyfish. In the end, it's not a matter of chance; it's just nature fine-tuning this winning strategy over a long period.
Jellyfish possess special cells filled with venom, called cnidocytes, to effectively ward off potential predators. When a fish or turtle gets too close, these cells release tiny stinging harpoons known as nematocysts, injecting a painful venom that quickly discourages the attacker. This defense can be very painful or even temporarily paralyze the predator, just long enough for the jellyfish to make a quiet escape. Even though some creatures like sea turtles have developed a resistance to this venom, for the most part, the stinging effect is usually enough to convince any potential assailant to look elsewhere.
The stinging cells of jellyfish, called cnidocytes or nematocysts, contain a tiny harpoon that is propelled at very high speed when the cell is stimulated mechanically or chemically.
Vinegar is often used as a first-line remedy to neutralize stinging cells in the event of a jellyfish sting, as it prevents the further release of toxins and reduces pain.
Some jellyfish have stinging tentacles that can remain active even after their death or detachment, which means they can sting long after being washed up on the beach!
The Irukandji jellyfish, a small Australian species measuring only a few centimeters, has venom powerful enough to cause a whole syndrome in humans called Irukandji syndrome, which leads to muscle pain, nausea, and hypertension.
No, not all jellyfish have the same level of toxicity. Some species may only cause mild irritation in humans, while others can trigger more severe reactions, even potentially fatal ones.
No. Although the stinging tentacles primarily serve to capture prey, they also play an important defensive role by protecting the jellyfish from potential predators.
The stinging cells (cnidocytes) have an autonomous mechanical and chemical functioning. Thus, they can continue to release their venom even after the death of the animal, as long as their mechanisms are intact.
Yes, some marine species, such as certain sea turtles, fish, and crustaceans, are immune to jellyfish stings, and even eat them regularly.
The activation of stinging cells (cnidocytes) is primarily triggered by physical stimuli (pressure, contact) combined with chemical stimuli. These combinations allow the cells to instantly release their venom under pressure into their target.
In case of a sting, gently remove any remaining filaments with tweezers or a rigid card, rinse thoroughly with seawater (not freshwater), and then apply vinegar to neutralize the venom. If symptoms persist or worsen, see a doctor promptly.
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