Jellyfish — swimmers’ new BFFs?Written by admin on June 29th, 2011
By Becky Fenson
Swimming is my passion. I learned to swim when I was 7 years old and have been drawn to the water ever since. I love it all—sprinting, long-distance swimming and everything in between. I once swam the English Channel, and I’ve swum around Manhattan Island numerous times.
But if there’s one thing that will get me out of the water, it’s jellyfish. While most swimmers shun jellies in order to avoid their painful stings—1,800 people were stung by mauve stingers off the coast of Florida over Memorial Day weekend—I’m more concerned about harming the jellyfish. I know that a misplaced stroke can easily damage a jelly’s delicate body. And now there’s another reason to give jellies their space: New research shows that these animals are far more complex than we ever imagined.
As a recent article in the New York Times reported, we now know that box jellyfish possess a complex visual system that allows them to navigate the murky swamps in which they live. Some of box jellies’ 24 eyes—yes, 24 eyes per jelly—are relatively simple and respond to light and shadow. But box jellies also have eyes that are surprisingly similar to our own—with lenses, retinas and corneas—that unerringly point skyward.
Why? In order to find food, box jellyfish need to stay within the tree canopy in the mangrove swamps where they make their homes. If they drift into the open lagoon, they will starve. These jellies look upward for navigational guidance.
Scientists have also discovered that jellies are not merely passive floaters, as was once thought. They dive down to reach still waters when tides start flowing out and also to find water that is salty enough to suit them. They can distinguish between friendly jellies and those who might eat them. When a moon jellyfish is touched by a predator jelly, the moon jelly swims safely away.
Jellyfish also have a centralized nervous system—places in their bodies where neurons cluster to take in sensory information and form an appropriate response. According to jellyfish expert David J. Albert of the Roscoe Bay Marine Biological Laboratory in Vancouver, British Columbia, jellies also have brains. In his research paper “What’s on the Mind of a Jellyfish?” Dr. Albert concludes that the answer is “a lot.”
I’m not surprised. Every day, we discover something new about the animals who share our world with us. Research has shown that fish can count and tell time. They are fast learners who think ahead, form complex social relationships and have unique personalities.
Octopuses play, just as dolphins and dogs do, and are often mischief-makers in aquariums. Otto, an octopus in a German aquarium, has been observed juggling the hermit crabs who share his tank. Lobsters recognize individual lobsters, remember past acquaintances and have elaborate courtship rituals.
I began to have empathy for my fellow swimmers—fish and other sea animals—not surprisingly, while in the water. When I lived in San Francisco, I spent so much time swimming in the bay that eating fish started to feel like eating my friends. Eventually, I decided to leave fish off my plate. Today I am vegan.
As we learn more about other animals, we begin to see that traits we once thought were uniquely human—such as feeling pain, enjoying life and forming close bonds—are shared, even with fish. This summer, as more of us take to the water, I hope that everyone will give at least a little thought to the jellies, fish and other sea animals they encounter. And perhaps some will take it a step further by passing on the seafood special at dinner and trying a humane vegetarian meal instead.
Becky Fenson is a manager for the PETA Foundation.