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BOB HIRSHON (host):
Pupil patterns. I’m Bob Hirshon and this is Science Update.
Round in humans, vertical in cats, horizontal in horses; why are pupils shaped differently? Martin Banks at the University of California, Berkeley studied over two hundred animals to find out.
MARTIN BANKS (University of California, Berkeley):
We showed that there really is a strong relationship between the kind of pupil an animal has and what their ecological niche is.
The findings, published in Science Advances, reveal that animals with vertical pupils like crocodiles are mostly predators that ambush their prey; vertical slits help gauge distances so they pounce accurately. Taller animals, like humans, tend to have round pupils. Advantages of vertical pupils disappear with height, and these predators chase prey rather than pounce. Finally, animals with horizontal pupils like horses and sheep are nearly always prey; horizontal openings provide wider panoramas to see approaching predators. I’m Bob Hirshon, for AAAS, the science society.