Is the bat’s brain wired for collective behaviour?

The same neurons that help bats navigate through space may also help them navigate collective social environments (Nature). Many mammals, including bats and humans, are believed to navigate with the help of a brain structure called the hippocampus, which encodes a mental ‘map’ of familiar surroundings. For example, as one walks around the neighbourhood or commutes to work, individual ‘place’ neurons in the hippocampus fire to indicate where the person is. Researchers used wireless neural recording and imaging devices to ‘listen in’ on the hippocampal brain activity of groups of Egyptian fruit bats as they flew freely within a large flight room, while tracking technology recorded the bats’ movements. They found that in this social setting, the bat’s place neurons encoded far more information than simply the animal’s location. As a bat flew toward a landing spot, the firing of place neurons also contained information about the presence or absence of another bat at that spot. And when another bat was present, the activity of these neurons indicated the identity of the bat they were flying toward, says a release. The bats spontaneously established a handful of specific resting spots within the flight room and followed very similar trajectories when traveling among them. The bats also showed strong preferences for flying toward specific “friend” bats, often landing very close to or even on top of each other.