After poring over the audio, the researchers say the calls not only identified the calling bat but also conveyed information about the bat being called. What's more, different calls were used for different situations – usually aggression-filled encounters, the team observed. Even friends or foes greeted each other with different calls.
"We have found that bats fight over sleeping positions, over mating, over food or just for the sake of fighting," said Yovel. "To our surprise, we were able to differentiate between all of these contexts in complete darkness, and we are confident bats themselves are able to identify even more information and with greater accuracy. They are, after all, an extremely social species that live with the same neighbors for dozens of years."
Yovel said the findings indicate bats aren't merely hard-wired for certain kinds of communication but instead learn to communicate different things, adding that his team's work could teach us more about the evolution of communication itself.
"Specifically," Yovel said, "one big unknown in the world of animal communication is their grasp on semanticity – i.e., when you hear the word 'apple' you immediately imagine a round, red fruit." Finding out that bat calls contain information about the caller and the bat being called, he noted, "implies that there is a recognition factor." Discovering context in the conversations similarly adds to our knowledge about animal communication.
Yovel is currenty studying the use of accents in bat calls as well as how the creatures form into different social groups.