Safe in the dark thanks to whiskers

Rats use their probes in different ways, depending on the lighting conditions

Versatile touch organ: The rat whiskers provide a wealth of information about their surroundings © University of Sheffield
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By a hair's breadth: rats are probing their surroundings with their whiskers to avoid collisions with obstacles. British scientists have now discovered that the rodents adjust their behavior deftly to the light conditions, depending on how well they know. In their study in the journal "Current Biology", the researchers even compare the use of the tactile hair with human fingers.

How sensitive the whiskers of rats are, scientists have known for some time. When they are exploring, the rodents wiggle these hairs back and forth. With the sense of touch of the hair, they feel walls and obstacles and can move safely even in the dark. The tactile behavior with the whiskers is apparently still much more versatile than previously thought.

Conscious, versatile use of whiskers

To further investigate this, behavioral researchers from Sheffield University, led by Tony Prescott, have taught several rats to look for food in various obstacle courses. In doing so they presented the experimental animals with various challenges: For example, they put the rats in the way of unexpected obstacles or let the animals run through total darkness. They filmed the rodents with high-speed cameras and paid particular attention to how the rats use their whiskers.

The result: Depending on how well the rats know their surroundings, they used the whiskers in very different ways: In a completely unknown obstacle course, the rats wag their hair in wide arcs to feel as much of their environment. Missing the light, stretch your hair forward. Apparently they are aware that in the dark more threatened by collisions with obstacles, and secure themselves when running forward.

A rat probes an obstacle with her whiskers © University of Sheffield

Whiskers touch like fingers

Study leader Prescott compares the deterrent with human behavior: "A person moving in the dark is likely to use their hands and fingers to feel and not bump into objects and obstacles." And the comparison with human fingers goes one step further: "In a familiar environment, such as your own home, you move faster and just feel your way forward to avoid unexpected clashes." Display

This is exactly what the rats do: Knowing their environment already, they do without the wandering of the "exploration mode", whether in the dark or in the light. Instead, they almost only feel forwards to move faster and safer.

Whiskers are common in mammals as a sense of touch. However, in the rats, the scientists have been impressed by how well the rodents use their probes: "The rat stretches its whiskers to where it thinks they can find the most useful information, " said Prescott, "just like we do with ours Fingertips do. "

(Current Biology, 2014; doi: 10.1016 / j.cub.2014.05.036)

(University of Sheffield, 08.07.2014 - AKR)