Bats Wiggle Their Heads or Ears To Hunt
Curiosity led a John’s Hopkins University researcher to discover how bats use adorable antics to search for prey.
Melville J. Wohlgemuth, a postdoctoral fellow from the Krieger School of Arts and Sciences Department of Psychological and Brain Sciences, discovered that bats waggle their heads and wiggle their ears to synch with the animal’s sonar vocalizations to help it hunt.
These adorable habits demonstrate how movement can enhance signals used by senses like sight and hearing in animals and even in humans.
Bats are known to use sonar-like echolocation emitting sounds and listening for the echo to find, track and catch prey.
The Curiosity Factor
Initially, Wohlgemuth wondered why the bats he works with cocked their heads to the side, just like his pet pug. This led him to investigate and found interesting answers behind the bat’s adorable antics.
Wohlgemuth said, “Its an adorable behavior, and I was curious about the purpose, said Melville J. Wohlgemuth, a postdoctoral fellow in the Krieger School of Arts and Sciences Department of Psychological and Brain Sciences. 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.”
Wohlgemuth and his team are the first to show how the head and ear movements factor into the hunt.
The Study
The researchers used a big brown bat as the subject of the study. This species of bat hunts both open and cluttered spaces.
The team trained bats to sit on a platform while tracking moving prey meal worms attached to a fishing line. To have a precise measure of the head and ear positions, the team attached used reflective markers to the top of the bat’s head and both ears.
The results were interesting. The researchers found the head waggles, about one per second. This occurred when the insect prey changed direction or moved erratically.
The ear movements happened as the worm grew closer. Though very small, the ear twitches help the bat hear the echoes it uses to track and capture the prey.
Watch the video to see how it works.
