Navigation and sensory ecology in wild bats – On-board sensing
Bats are the only flying mammals. They exhibit extreme navigational abilities such as seasonally migrating over thousands of kilometers and nightly commuting over many dozens of kilometers, relying on different sensory modalities when doing so (e.g., vision, magnetic sensing and bio-sonar or echolocation). Studying animals in the wild is extremely difficult. Bats constitute major challenges because of their small size (usually less than 30 grams). Thanks to their constant emission of sound to sense the environment, bats allow a rare opportunity to infer a wild animal's behavior by recording it acoustically. For example, when a bat emits a sequence of ever-shortening calls with decreasing intervals between them, we know that it is intercepting prey. In the Neuro-ecology laboratory, we specialize in designing and developing miniature sensors that can be mounted on wild bats. These include GPS for tracking movement and ultrasonic microphones for recording bat bio-sonar to infer the bat's behavior. We have the ability to mount almost any other sensor on a wild bat in order to study its behavior. Some examples include: accelerometers to follow its movement, magnetic and light sensors to monitor its environment and EEG or temperature sensors to record its physiology. Such an intimate monitoring of a wild animal also enables us to 'close the loop' and examine how the animal reacts to changes in its habitat. By first using GPS to reveal where the bat forages, we can then manipulate its environment and register its reaction, thus studying how wild animals adjust to changes in the environment. Some examples include, removing known food sources or offering new ones, increasing or decreasing competition and more. Thanks to our technology we can therefore study animal behavior in its full complexity in the wild.