Jason Daley in Smithsonian:
Plenty of animals communicate with one another, at least in a general way—wolves howl to each other, birds sing and dance to attract mates and big cats mark their territory with urine. But researchers at Tel Aviv University recently discovered that when at least one species communicates, it gets very specific. Egyptian fruit bats, it turns out, aren’t just making high pitched squeals when they gather together in their roosts. They’re communicating specific problems, reports Bob Yirka at Phys.org. According to Ramin Skibba at Nature, neuroecologist Yossi Yovel and his colleagues recorded a group of 22 Egyptian fruit bats, Rousettus aegyptiacus, for 75 days. Using a modified machine learning algorithm originally designed for recognizing human voices, they fed 15,000 calls into the software. They then analyzed the corresponding video to see if they could match the calls to certain activities.
They found that the bat noises are not just random, as previously thought, reports Skibba. They were able to classify 60 percent of the calls into four categories. One of the call types indicates the bats are arguing about food. Another indicates a dispute about their positions within the sleeping cluster. A third call is reserved for males making unwanted mating advances and the fourth happens when a bat argues with another bat sitting too close. In fact, the bats make slightly different versions of the calls when speaking to different individuals within the group, similar to a human using a different tone of voice when talking to different people. Skibba points out that besides humans, only dolphins and a handful of other species are known to address individuals rather than making broad communication sounds.
More here.
