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Bat Light

July 31, 2014

Bats navigate using polarized light.



Stefan Grief 2013_07_18_0883

Tracking bats just after sunset. (Stefan Greif)

How bats see the sky. I’m Bob Hirshon and this is Science Update.

The old saying “blind as a bat” is just plain wrong, according to zoologist Richard Holland of Queen’s University in Belfast. In fact, he says bats use the polarized light given off at sunset to fine-tune their internal compass for navigation.

RICHARD HOLLAND (Queens University, Belfast):

This polarization pattern appears as a dark band at a 90 degree angle to the sun, so if you’re standing looking at the sun you would see a dark band going across the sky above you.


This is caused by the way the sun’s rays are scattered. Holland and his team found that greater mouse-eared bats use this information to find their way around the night sky, sometimes traveling hundreds of kilometers in a single night. He says birds were already known to calibrate their internal compass using polarized light, but this is the first time the phenomenon has been documented in a mammal. I’m Bob Hirshon, for AAAS, the science society.

The research appears in the journal Nature Communications.

Story by Susanne Bard