Bats may be using an innate understanding of physics to track their prey in the dark. Institute neurobiologists trained Egyptian fruit bats to fly to food in a dark lab. They found that in some situations the bats sweep their sonar to either side, catching their "prey" on the beam's slope, while at other times they point their beams head-on. Some physical calculations showed that the changes in intensity near the slope help in getting a fix on the target's direction - a very efficient strategy for localizing targets - while the direct beam is preferable for discerning a hard-to-identify target - say a fruit hanging in a tree. Prof. Nachum Ulanovsky gave a podcast interview to Science, explaining the study.