Friday, 25 July 2014

Polarized Light Helps The Greater Mouse-Eared Bat Navigate

July 24, 2014

Rayshell Clapper for – Your Universe Online

The manner in which bats use echolocation has long been of interest to scientists, but new research shows that bats use more than echolocation to get around. In fact, the Natural Environment Research Council (NERC) recently announced a new discovery about the greater mouse-eared bat and how it navigates.

The greater mouse-eared bat uses “polarization patterns in the sky to navigate…The bats use the way the Sun’s light is scattered in the atmosphere at sunset to calibrate their internal magnetic compass, which helps them to fly in the right direction,” according to a study published in Nature Communications.

The pattern of light polarization is the way light vibrates in one direction. In other words, sunlight scatters in the sky to create polarized light patterns. Studies show that these are mostly invisible to the human eye although with some training and know-how on what to look for humans can perceive polarization. However, science currently does not show a purpose for polarization patterns for human use.

According to National Geographic‘s Katie Langin, the study co-authors, Dr. Richard Holland and Stefan Greif of Queen’s University Belfast and colleagues from Tel Aviv University, took 70 female greater mouse-eared bats in Bulgaria. “The team placed each bat in a box that simulated polarized light at sunset. Some bats saw the natural pattern; others saw a band of polarization that was rotated 90 degrees…Next, they displaced the radio-tagged bats more than 14 miles (20 kilometers) from their roosting cave and tracked their movements in the night.”

What the researchers found was the bats with the altered polarization pattern of 90 degrees “went in directions that were rotated 90 degrees from the correct orientation.” However, the bats that were placed in the box with the correct simulated polarization found their way home.

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