Trivia Tuesday: 10 Facts About Sea Jellies — Including Why Not to Call Them Jellyfish

Credit: Thinkstock

We love animals. In fact, we love them so much that we geek out over learning little-known animal facts, and we suspect we're not the only ones. Every Tuesday, we'll share a few fun animal facts with you from experts at zoos, parks and aquariums all over the country (and maybe even beyond).

10 Things You Don't Know About Jellies

Today's expert: Mark Schick, Special Exhibit Collection Manager at Shedd Aquarium. Schick has been working with Shedd for over 15 years and has been working on and off with jellies for about 10 years. He's a self-professed geek about them and recently shared 10 fun facts about these super simple organisms.

  • You may know them as "jellyfish," but the right term is jellies as they are not actually fish.
  • Jellies live in every ocean and at every depth. They can live in warm, shallow water as well as the deepest, darkest, coldest water.
  • One of the defining characteristics of jellies is that they all sting. Jelly-like creatures that don't sting, such as comb jellies, are not true jellies.
  • Speaking of stinging, some jellies have a sting so powerful it can kill a person; others can sting you and you'd never even know.
  • Jellies come in all sizes, from teeny tiny to truly enormous. In fact, the Lionsmane jelly can grow to be 6-8 feet in diameter and 70 feet long.
  • A jelly's size is determined by its food source. If it has plenty to eat it will grow. If it doesn't have lots of food available, it won't starve; it simply won't get bigger.
  • The biggest predator to jellies is other jellies. Most of these cannibalistic creatures eat other species of jelly and leave their own alone.
  • Jellies only have one hole, so everything — food, poop, babies, everything -- goes in and out of that hole.
  • If a jelly stings you, forget the old advice to pee on it. That's just bad hygiene . And anyway, it doesn't work. Urine contains fresh water, which actually makes the sting worse. Your best bet is to scrape off any remaining pieces of tentacle with something like a credit card (not your hand!), then cover the area with vinegar, meat tenderizer, or even mustard.
  • There are thousands of species of jellies in a huge variety of colors — red, blue, even glow in the dark. As a matter of fact, a chemical isolated from one bioluminescent (or glowin the dark) species is being used in drug research. Scientists can tack that chemical onto different genes and cells — even cancer cells — and track it by just looking at the animal and shining a blacklight on it because the cell will glow green.

For more information on these sea creatures, check out the Shedd Aquarium's Jellies exhibit and other Shedd articles.

Be sure to check in next week for more fun animal facts on Trivia Tuesdays.

Join the Conversation

Like this article? Have a point of view to share? Let us know!