95% H20 + 5% Jell-0 = ???

"Jellyfish (jellies) are made of 95% water - 5% of a Jell-O type substance, have no brain, and therefore are totally incapable of governing any of their actions." From my childhood until well into my sixties, the above quotation was a truism that was locked in stone. It wasn't until recently that I learned just how foolish that statement was. Let's take a look at some of the facts.

Photo by Charlotte Clayton
Taken at Discovery Place, Charlotte, NC

• Q. Are jellies able to see?
• A. Yes, "killer box jellyfish," or "sea wasp," Mitrocoma cellularia, prefer to congregate in sunny areas. If they venture into shadowy areas they will reverse course and return to their sunny spot. Even blocking sunlight using a hand will cause them to reverse direction. Their "vision" may help them with feeding, navigation and reproduction.

• Q. Do jellies have a sense of smell?
• A. Actually, the Mitrocoma cellularia, "cross jelly," are capable of detecting chemical scents as varied as oil and zooplankton, and in the case of the latter, swim to it.

• Q. Can jellies produce light?
• A. The "Crystal jelly," Aequorea Victoria, is capable of producing light through a chemical reaction, turning the color blue into green. This light is used to scare off predators and in mating.

• Q. Are there immortal jellies?
• A. Theoretically, a Turritopsis nutricula, "immortal jellyfish," is capable of eternal life. Basically, this creature after it reaches sexual maturity is able transform itself from "adulthood" back to "babyhood." While in theory it would seem the immortal jellie could live forever, in reality it's simply not true. Realistically the "forever" would become a meal for a jellie eating predator.

Uncle Bear is a writer and researcher in North Carolina. He can be reached through:

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