Written by Margaret Badore
Jellyfish and jelly-like sea creatures come in an immensely diverse range of forms. Animals that are typically called jellyfish belong to the phylum Cnidaria, which includes over 10,000 species. However, some jelly-like animals, like the comb jelly, belong to the phylum Ctenophora. This taxonomic difficulty has lead marine biologists to ask if there’s even such a thing as a jellyfish.
Let’s set those questions aside for now, and dive together into the fascinating world of creatures commonly known as jellyfish.
1. Some jellyfish can glow in the dark
Many jellyfish have bioluminescent organs, which emit light. This light may help them in a number of different ways, like attracting prey or distracting predators.
2. Jellyfish can clone themselves
If a jellyfish is cut in two, the pieces of the jellyfish can regenerate and create two new organisms. Similarly, if a jellyfish is injured, it may clone itself and potentially produce hundreds of offspring.
3. Some jellyfish are immortal
There are two phases to jelly life: the stationary polyp stage and the mobile medusa phase. It’s the medusa phase that we’re usually referring to when we talk about jellyfish. Typically, jellies start as polyps and develop into medusas, but the Turritopsis nutricula has earned it the nickname “the immortal jellyfish” for having the ability to travel backward to the polyp stage in times of stress.