You could describe evolution as the continuing race to eat while avoiding being eaten. Well, today we’ll hear an example of evolution in action: an arms race with weapons of sound being waged by bats and the moths that they prey upon. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.
Most bats use echolocation to find their prey.
ambience: Bat echolocation
Using high frequency sound, a bat creates a sonic image of its surroundings and the potential food items, such moths, nearby. These ultrasonic signals have been slowed down eight times in this recording so that we can hear them.
Unfortunately for the bat, some moths, such as the Tiger moth, can hear these signals. The moths respond with their own calls which interfere with the bat’s echolocation, and allow the moth to escape being eaten. We’ve slowed down the recording of the moth sounds thirty times so that we can hear them.
ambience: moth clicks
“This is an evolutionary arms race and there’s lots of evidence that the insects are continually trying to evade the bats and there’s evidence that the bats are continuously trying to get better and better.”
Bill Conner is a Professor of Biology at Wake Forest University in North Carolina. He tells us that bats are fighting back, finding new ways to catch their prey.
“One example is that certain bats produce very, very soft sounds. They’re whispering bats and we believe that these sounds are produced in order to so that the bats can still echolocate but the moths can’t quite hear them.”
Pulse of the Planet is presented by the American Museum of Natural History. Additional funding for this series has been provided by the National Science Foundation. I’m Jim Metzner.