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Brainless Navigation

June 1, 2011

Although they lack real brains, box jellyfish can follow landmarks above the water’s surface.



Brainless orienteering…I’m Bob Hirshon and this is Science Update.

If you’re proud of your sense of direction, here’s something humbling: Box jellyfish can follow landmarks, and they don’t have brains. The box jellies congregate near the underwater roots of mangrove trees, where they nimbly steer around the roots to catch shrimp. Now, University of Copenhagen biologist Anders Garm and his colleagues have shown how they find their way back if they’re washed out to sea.

ANDERS GARM (University of Copenhagen):

And underwater there is no cues to find their way back. Instead, they’ve found an ingenious system where they look through the air, and see the canopies of the trees, and use this for navigation.


In Garm’s experiments, jellies in closed tanks swam toward the canopy from up to 26 feet away. But when the canopy was hidden, the jellies just swam randomly. They’re the first marine invertebrates shown to follow landmarks above the water’s surface. I’m Bob Hirshon, for AAAS, the science society.