To orient themselves and communicate, the bats (scientifically, chiroteri) emit ultrasonic – ultrasound signals – that researchers detect and record with sophisticated technological devices called “Bat detector”. Now the “Biodiversity and Conservation” magazine publishes a scientific work that opens the study of bats to anyone who owns a smartphone. The work, led by Fabrizio Gili of the Department of Life Sciences and Biology of the Systems of the University of Turin, has tested the effectiveness of common mobile telephony devices (smartphones and tablets) to detect the signals of low -frequency chiropteri, comparing it with that obtained using professional “bat detector”. In parallel, a pilot project of “Citizen Science” started (scientific research conducted widely by citizens interested in science) to verify the applicability of cell phones on the field. The first results are absolutely surprising.
Chirotteri are the second largest group among mammals: the known species are more than 1470. Distributed all over the world with the exception of Antarctica, bats have a fundamental ecological role as parasites regulators, pollinators and seed dispersion carrier. In Italy and Europe, all species of chiroteri are protected: monitoring the health of their populations is mandatory and regulated by the European Union. The first phase of the research was conducted in Turin.
It has been discovered that at least nine species of European chiropteri can be monitored using mobile devices, With a quantity and quality of recordings comparable to that obtained through the Bat detector.
https://www.lastampa.it/speciale/scienza/il-cielo/2025/03/26/news/esperimento_pipistrelli_smartphone_torino-15073561/
Turin Experiment: Listening to Bats with a Smartphone
In the bustling city of Turin, Italy, a groundbreaking experiment is harnessing the power of everyday technology to unlock the secret world of bats. Researchers from the University of Turin have pioneered a novel approach to biodiversity monitoring, using smartphones to listen to bat echolocation calls. This innovative study, conducted between August 2021 and October 2022, demonstrates how mobile devices can transform citizen science and provide critical insights into the lives of these elusive nocturnal creatures.
The Science of Bat Echolocation
Bats navigate and hunt using echolocation, emitting high-frequency sound waves that bounce off objects and return as echoes, allowing them to “see” their surroundings in the dark. These ultrasonic calls, typically beyond the range of human hearing (above 20 kHz), vary by species and purpose—whether foraging, socializing, or avoiding obstacles. Traditionally, studying these calls required expensive, specialized equipment like professional bat detectors, limiting large-scale monitoring efforts. However, the Turin experiment flips this paradigm by leveraging the ubiquitous smartphone.
The Experiment in Action
Led by researchers from the Department of Life Sciences and Systems Biology at the University of Turin, the study tested whether smartphone microphones could effectively record bat calls. Sampling occurred at six urban and suburban sites in Turin, carefully selected to avoid excessive noise pollution. The team paired smartphones with a professional bat detector, mounting both on 2.5-meter poles under open skies, at least 3 meters from obstacles. Recordings were made from sunset to four hours later, under calm weather conditions, capturing the echolocation and social calls of nine European bat species, including the soprano pipistrelle (Pipistrellus pygmaeus).
To broaden their dataset, the researchers also recorded calls near a maternity colony of the rare greater noctule (Nyctalus lasiopterus) in Seville, Spain, with assistance from the Doñana Biological Station. The smartphones tested included models from Samsung, Huawei, Xiaomi, and Apple, each evaluated for spectrogram quality and peak frequency accuracy compared to the professional detector.
Surprising Results
The findings were striking. Spectrograms—visual representations of sound frequencies—produced by smartphones showed high similarity to those from the bat detector, with Huawei leading at a 0.90 correlation, followed by Xiaomi (0.86), Samsung (0.74), and Apple (0.69). Peak frequency differences were minimal, ranging from 0.1 kHz (Huawei and Apple) to 0.5 kHz (Xiaomi), proving that smartphone microphones could reliably capture bat calls. This success hinged on the devices’ ability to record low-frequency bat calls (15–120 kHz), a range accessible to many modern smartphone microphones when paired with appropriate software.
The experiment also highlighted practical advantages. Smartphones are portable, affordable, and widely available, unlike professional detectors costing hundreds or thousands of dollars. By equipping volunteers with their own devices, the study showcased the feasibility of large-scale, participatory monitoring programs.
Implications for Citizen Science
This Turin experiment builds on a growing trend of using mobile technology for ecological research. Citizen science, where volunteers contribute to data collection, has long been a cornerstone of biodiversity monitoring, but high equipment costs often restricted participation. Now, with smartphones as viable tools, anyone can join the effort to track bat populations—a critical task given the threats bats face from habitat loss, climate change, and diseases like White-Nose Syndrome.
The study’s authors envision a future where apps could process bat calls in real-time, allowing users to identify species on the spot. While the Turin team used post-processing to analyze recordings, existing tools like the Echo Meter Touch 2 (a smartphone-compatible detector) already offer auto-identification, hinting at what’s possible with further development.
Challenges and Next Steps
Despite its success, the experiment revealed limitations. Urban noise—traffic, human activity, or wind—could interfere with recordings, necessitating careful site selection. Smartphone microphone quality also varies by model, and not all devices can capture the full ultrasonic range without hardware modifications. Future research could explore integrating low-cost ultrasonic attachments or refining apps to filter background noise.
The Turin team plans to expand their work, testing more species and environments, and engaging local communities in Turin and beyond. By open-sourcing their methods (funded through the University of Turin’s CRUI-CARE Agreement), they hope to inspire global adoption of this approach.
A Window into the Night
The Turin experiment is more than a technical feat—it’s a bridge between science and society. Bats, often misunderstood or overlooked, play vital roles as pollinators, seed dispersers, and pest controllers. Listening to them with a smartphone not only demystifies their world but empowers people to protect it. As of March 26, 2025, this study stands as a testament to how innovation can amplify our connection to nature, one ultrasonic chirp at a time.
