Bat friend or bat foe? It's all in the call
It's well known that bats use sound to navigate their environment, but new research out of Tel Aviv University (TAU) indicates that the noises the flying mammals make actual serve a host of other functions including conveying information about the caller and addressee, marking each other as friend or foe, and indicating what particular squabbles are about.
To begin untangling the mass of noises found in bat caves, the researchers assembled 22 Egyptian fruit bats and recorded their sounds for 75 days. This gave them a dataset of about 15,000 vocalizations. By analyzing those, they were able to begin to understand what different noises indicated.
"When you enter a bat cave, you hear a lot of 'gibberish,' a cacophony of aggressive bat noise – but is this merely 'shouting' or is there information amid the noise?" asked Yossi Yovel of the Department of Zoology at TAU's Faculty of Life Sciences. "Previous research presumed that most bat communication was based on screaming and shouting. We wanted to know how much information was actually conveyed — and we wanted to see if we could, in fact, extract that information."
And extract they did. In addition to the disposition and identification information, the researchers were able to tease out the data to such a point that they could figure out what certain fights were about and even whether certain interactions would end well or badly. They also found that the most common tussles were over sleeping positions, mating, food or "just for the sake of fighting."
"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," said Yovel.
"Studying how much information is conveyed in animal communication is important if you're interested in the evolution of human language," he added.
The work of the researchers has been published in the journal Scientific Reports.
Source: Tel Aviv University