It’s been long known that bats use unusual echolocation skills and their own magnetic compass to navigate. In a brand new study, scientists have discovered bats also use polarized light. They’re the first mammals known to use it.
What is polarized light? Basically, it’s the way sunlight is scattered in the atmosphere.
Other animals that take advantage of polarized light include birds, anchovies and certain beetles.
As part of the study, which was published in Nature Communications, a team of zoologists put bats in boxes with polarizing windows before observing them fly home. What they found surprised them. The bats used polarized light to help calibrate their internal compass.
“We know that other animals use polarisation patterns in the sky, and we have at least some idea how they do it: bees have specially-adapted photoreceptors in their eyes, and birds, fish, amphibians and reptiles all have cone cell structures in their eyes which may help them to detect polarisation,” says Dr Richard Holland of Queen’s University Belfast, co-author of the study.
“But we don’t know which structure these bats might be using.”
These polarization patterns can still be seen long after the sun sets or even on a cloudy day. Dung beetles have even been known to use polarization patterns from moonlight to better orient themselves.
Scientists hope a better understanding of how bats navigate can help them protect the bats. Several bat species are on the decline across Europe with wind turbines being a primary cause. “It’s most common in migratory species, with around 300,000 bats affected every year in Europe alone. You just find bats dead at the bottom of these turbines,” says Holland.
One option that could curtail the effect on bats would be to reduce turbine activity during peak migration according to Holland.