How ASU students are making Phoenix’s 10,000 bats audible

A tunnel on the border of Phoenix and Paradise Valley has sheltered about 10,000 bats since the 1990s. Most people do not hear them: their calls are pitched above the range of human hearing. Arizona State University researchers are working with high school students to make those sounds perceptible and explore what listening can teach people about the species living alongside them.

The Humanities Institute-funded project pairs field recording with creative work, including music made from bat calls and city sounds. Its broader aim is to help students imagine the relationships between people and other species, said principal investigator Dan Gilfillan. That question has implications beyond the classroom: researchers plan to share their findings with the Maricopa Flood Control District as it develops community outreach materials about endangered bats.

How students captured the sounds

Working with Arizona School for the Arts, students used two recording methods. A network of microphones captured spherical, 360-degree sound, allowing listeners to distinguish noises coming from different directions or moving across the space. The approach, known as ambisonic recording, can make a buzzing insect seem to travel from left to right.

Students also used ultrasonic recorders to capture sounds at frequencies beyond human hearing. Software then transformed those recordings into sounds people could hear. After recording, the students created responses that included a story told from a bat’s perspective and recordings of places that mattered to them.

What comes next

The project treats creative responses as a way to listen more closely and build what researchers call ecological imagination: the ability to picture oneself within a web of relationships. Gilfillan said that recognizing how other beings sense and communicate is important to imagining futures that include them.

More field recordings are planned, and the researchers will share their findings with the flood control district. The project description also says its team will host a public lecture and workshop during Humanities Week with David George Haskell, a two-time Pulitzer Prize nominee. It does not give dates for the event or specify when the district’s outreach materials will be completed.

This report draws on information from news.asu.edu.