You know that adorable habit dogs have of tilting their head from side to side while listening? Although the behavior in dogs is not fully understood, new research finds that bats do the same sort of thing, waggling their heads in the most adorable way.
And while we may not have previously understood why dogs do this, Johns Hopkins University researcher Melville J. Wohlgemuth suggests these bat movements may serve to enhance signals used by senses like sight and hearing — possibly even in dog, cats, and even humans.
It’s commonly known that bats rely on echolocation to detect, track and catch prey. But Wohlgemuth was curious to find out what purpose these mysterious head waggles and ear wiggles served. Did they actually factor into the hunt? Or were they just another endearing trait?
It’s commonly known that bats rely on echolocation to detect, track and catch prey. But Wohlgemuth was curious to find out what purpose these mysterious head waggles and ear wiggles served. Did they actually factor into the hunt? Or were they just another endearing trait?
“It’s an adorable behavior, and I was curious about the purpose,” Wohlgemuth, a postdoctoral fellow in the Krieger School of Arts and Sciences’ Department of Psychological and Brain Sciences, said in astatement. “I wanted to know when bats were doing this and why. It seemed to occur as bats were targeting prey, and that turns out to be the case.”
To find out, Wohlgemuth and his team trained big brown bats (Eptesicus fuscus) to sit on a platform while tracking mealworms attached to a fishing line. After training, reflective markers were attached to the bats’ heads and ears, which allowed the researchers to precisely measure the head and ear positions at all times while using high-tech recording devices.
The found that the head waggles occurred about once per second, usually when the prey changed direction or moved erratically. Subtle ears movements also occurred as the prey grew closer. The researchers say these tiny and almost imperceptible ear twitches may help the bats hear the echoes it uses to track and capture the prey. And on a millisecond time scale, the researchers found that all these movements coordinated with the bats’ vocalizations, which may add to their pinpoint targeting accuracy.
Previous research on how animals and humans localize sound sources missed the importance of head waggles and ear movements, said Johns Hopkins professor and neuroscientist and co-author Cynthia F. Moss. She adds that this may be due to the fact that most labs typically observe the subject with a fixed or restrained head position. Animals don’t operate like that in the real world.
Moss compares the bats’ head and ear movements to other species that use active sensing, such as the ear movements of a cat on alert or the head tilt of an owl.
“By studying these movements,” she said, “we as humans can get insight into how movement helps animals sense their environment.”
Results are published in the open access journal PLOS Biology. More videos available here.
The found that the head waggles occurred about once per second, usually when the prey changed direction or moved erratically. Subtle ears movements also occurred as the prey grew closer. The researchers say these tiny and almost imperceptible ear twitches may help the bats hear the echoes it uses to track and capture the prey. And on a millisecond time scale, the researchers found that all these movements coordinated with the bats’ vocalizations, which may add to their pinpoint targeting accuracy.
Previous research on how animals and humans localize sound sources missed the importance of head waggles and ear movements, said Johns Hopkins professor and neuroscientist and co-author Cynthia F. Moss. She adds that this may be due to the fact that most labs typically observe the subject with a fixed or restrained head position. Animals don’t operate like that in the real world.
Moss compares the bats’ head and ear movements to other species that use active sensing, such as the ear movements of a cat on alert or the head tilt of an owl.
“By studying these movements,” she said, “we as humans can get insight into how movement helps animals sense their environment.”
Results are published in the open access journal PLOS Biology. More videos available here.
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