You would expect football players to run interference, but it seems that the animal kingdom is also full of unique examples. The Mexican free-tailed bat (Tadarida brasiliensis) is one of those examples. It blocks the competitor’s hunting abilities, a new study says, by using acoustic jam calls.
Scientists noted that the bats use this call to send rival’s echolocation out of commission. Bats use echolocation (a process through which sound waves are made to bounce off nearby objects, much like sonar) for orientation and hunting purposes.
So it is impossible for a bat to zero in on prey when this important tool isn’t properly functioning.
The new study was published in Science magazine on November 6th and suggests that the Mexican free-tailed bat begins making such interference calls when other bats from the same species are out hunting.
This behavior was discovered by accident when Aaron Corcoran, biology postdoctoral student at the University of Maryland, was studying sonar disturbances caused by Grote’s Tiger Moths. He was at Arizona’s –New Mexico border attempting to understand how this moth jams the sonar of big brown bats when he saw that free-tailed bats make their own calls.
Corcoran decided to review this data in the lab and made the connection. Mexican free-tailed bats, he saw, made unique calls similar to ultra-fast clicking sounds that tiger moths usually use to block the big brown bat’s sonar.
“I had jamming signals on the brain, and so I needed to convince myself that this was true and I wasn’t just imagining the similarity.”
Corcoran though when he first came up with the hypothesis that these bats were attempting to block each other’s hunting calls.
He therefore attempted to exclude any other explanations. Corcoran and his colleagues began recording bat interactions by using a high-speed camera and microphones set up to pinpoint the bat’s location. The team came to the conclusion that it was only when a bat was emitting what they called a “feeding buzz” that jamming began.
Later on, Corcoran played recordings of this peculiar signal in an attempt to see whether the behavior of other Mexican free-tailed bats in the wild would be influenced. If the sounds were played just as the bat was catching an insect, the likelihood of catching its prey decreased by 85.9 percent.
Altering the pitch of the signal did not produce the same effect.
“I had no idea that such a behavior existed until now. It’s absolutely fantastic work.”
John Ratcliffe, biologist at the University of Toronto said.