Why Do Brown Bats Stop Feeding During Fireworks? #ASA190

What acoustics can teach us about animal behaviors during disruptive events like firework shows.

PHILADELPHIA, May 12, 2026 — Firework shows are controversial in this day and age. While beautiful, fireworks are loud, bright, and smoky, and they can be dangerous to the surrounding environment, releasing contaminants into the air and frightening both pets and wildlife alike.

Luckily, cities across the country are taking initiative to explore the impact of fireworks on residents and wildlife. In October 2025, the City of Capitola, California, and Integral Consulting conducted a study to determine the effect of their annual firework show on the surrounding animal population in the Monterey Bay Marine Sanctuary.

Integral Consulting’s Kerri Seger and Greg Cotten used the opportunity to observe how the fireworks impacted the feeding patterns of brown bats. They will present their findings Tuesday, May 12, at 10:15 a.m. ET as part of the 190th Meeting of the Acoustical Society of America, running May 11-15.

Person in red jacket views off image through a thermal scope at night with fireworks in background.

Photos from the October firework show in Capitola, California. Researcher Greg Cotten views the bats through a thermal scope (right). Credit: Amy Howk, Integral Consulting

Five days before the Capitola firework show, Cotten set up a microphone to record a normal night of bat activity, which could serve as a baseline. From data recorded the same night as the fireworks display, they identified bat behaviors based on the echolocation calls they heard: Some sounds corresponded to searching behaviors, others to food capture behavior.

On the night of the 31-minute firework show, Seger and Cotten recorded the bats for half an hour before the show, during the show, and half an hour afterward. They noticed that the bats were searching for and catching food steadily before the show, but during the fireworks, they were unsuccessful in catching any prey, despite searching.

“There is a measurable effect of the fireworks’ noise and/or lights on bats’ feeding, showing that bats can’t exactly eat dinner in peace while they are happening,” Seger said.

Then, after the show ended, the bats returned quickly to resume hunting but searching and catching were greatly reduced from their pre-show efforts. Cotten wondered if this result might be because of a “moth to a flame” effect.

“This phrase originated from Greg’s interpretation of me explaining what I heard in the data after my first listen,” Seger said.
The quick return to feeding could have been influenced by the bats’ natural prey — insects and moths — flocking to the bright lights of the fireworks, but it could also be totally unrelated to the availability of the food, instead caused by the bats feeling safer to return to a quiet area.

Seger said that these theories will require more testing beyond acoustics — for instance, directional microphones would help determine the numbers and directions of the bats and their prey, giving insight into their attraction to — or repulsion from — the explosions.

Seger believes that this work has the chance to influence firework policy in the city of Capitola.

“The city funded the study because they were interested in effects to wildlife from their fireworks show,” Seger said. “I suspect they will take the results seriously and have a concerted discussion about what they might or might not decide to permit in the future.”

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More Press Releases

Do short-tailed fruit bats suffer hearing damage after noise exposure?

Keegan Eveland1 – kevelan1@jhu.edu
Bluesky: keeganeveland
Instagram: @keveland3

Capshaw G.1,2*
Lauer, A. 2,3,4
Moss, C.F.1,3,5,6

  1. Department of Psychological and Brain Sciences
    Johns Hopkins University
    Baltimore, MD, 21218
  2. Department of Otolaryngology-Head and Neck Surgery
    Johns Hopkins University School of Medicine
    Baltimore, MD, 21205
  3. The Solomon H. Snyder Department of Neuroscience
    Johns Hopkins University School of Medicine
    Baltimore, MD, 21205
  4. Center for Functional Anatomy and Evolution
    Johns Hopkins University School of Medicine
    Baltimore, MD, 21205
  5. Department of Mechanical Engineering
    Whiting School of Engineering
    Johns Hopkins University
    Baltimore, MD, 21218
  6. Kavli Neuroscience Discovery Institute
    Johns Hopkins University
    Baltimore, MD, 21218

*Co-first author

Popular version of 2aAB8 – Noise-induced hearing loss susceptibility in the short-tailed fruit bat (Carollia perspicillata)
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/index.php?page=Session&project=ASASPRING2026&id=4082866

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Hearing is crucial to many animal species that use sound to navigate, communicate, and avoid predators. Despite its importance, hearing in many animals is damaged by exposure to loud sounds. One exception is the echolocating bat, an animal that navigates in the dark using sound alone. While some vertebrates like fish and birds can regenerate the sensory cells that support hearing, mammals cannot, and hearing loss, caused by aging and exposure to loud noise, is common among mammals. This is what makes bats an intriguing case: bats can emit extremely loud ultrasonic calls (110 – 140 dB), the equivalent of a rock concert, yet some species show exceptional resistance to both age-related and noise-induced hearing loss.

However, not all bats are equally resistant to hearing loss; the ability to maintain hearing after noise exposure and into old age appears to reflect the degree of reliance on hearing for survival. For example, the big brown bat (Eptesicus fuscus), uses its hearing to hunt insects and is more resistant to both age-related and noise-induced hearing loss than the Egyptian fruit bat (Rousettus aegyptiacus), a frugivorous species that relies more heavily on vision for navigation and loses its hearing with age. This raises the question: What mechanisms make some bat species more resistant to hearing loss than others?

In this study, we examined noise susceptibility in the short-tailed fruit bat (Carollia perspicillata), which represents an interesting middle ground between these two species. Like the big brown bat, short-tailed fruit bats rely primarily on echolocation for navigation. However, like the Egyptian fruit bat, it feeds mainly on fruit and can supplement echolocation with other senses such as smell during foraging.

We hypothesize that short-tailed fruit bats maintain their hearing sensitivity even after exposure to loud noise, given their reliance on echolocation for navigation. To test this, we measured the bats’ hearing before and after one hour of exposure to intensely loud, 110 dB noise. We used two complementary methods: auditory brainstem responses, which assess auditory nerve and brainstem responses to sound, and otoacoustic emissions, which evaluate the functionality of the sensory cells that support cochlear amplification in the inner ear.

Our preliminary results show no long-term hearing damage following noise exposure, suggesting that short-tailed fruit bats possess protective mechanisms to preserve their most critical sense. These findings strengthen evidence that echolocation-dependent bats protect their hearing against noise damage better than those that primarily rely on other senses (such as vision). Understanding the biological mechanisms underlying this protection could have implications beyond bats and may reveal new strategies for preventing noise-induced hearing loss in other species.

 

Comparison of sonar reliance and hearing loss susceptibility among Egyptian fruit bats, short-tailed fruit bats, and big brown bats.

Bats could help the development of AI robots

Rolf Müller – rolf.mueller@vt.edu
X (twitter): @UBDVTLab
Instagram: @ubdvtcenter
Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia, 24061, United States

Popular version of 4aAB7 – Of bats and robots
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0027373

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Given the ongoing revolution in AI, it may appear that all humanity can do now is wait for AI-powered robots to take over the world. However, while stringing together eloquently worded sentences is certainly impressive, AI is still far from dealing with many of the complexities of the real world. Besides serving the sinister goal of world-domination, robots that have the intelligence to accomplish demanding missions in complex environments could transform humanity’s ability to deal with fundamental key challenges to its survival, e.g., production of food and regrowable materials as well as maintaining healthy ecosystems.

To accomplish the goal of having a robot operate autonomously in complex real-world environments, a variety of methods have been developed – typically with mixed results at best. At the basis of these methods are usually two related concepts: The creation of a model for the geometry of an environment and the use of deterministic templates to identify objects. However, both approaches have already proven to be limited in their applicability, reliability, as well as due to their often prohibitively high computational cost.

Bats navigating dense vegetation – such as in rainforests of Southeast Asia, where our fieldwork is being carried out – may provide a promising alternative to the current approaches: The animals sense their environments through a small number of brief echoes to ultrasonic pulses. The comparatively large wavelengths of these pulses (millimeter to centimeter) combined with the fact that the ears of the bats fall not too far above from these wavelengths on the size scale condemns bat biosonar to poor angular resolution. This prevents the animals from resolving densely packed scatterers such as leave in a foliage. Hence, the echoes that bats navigating under such conditions have to deal with inputs that can be classified as “clutter”, i.e., signals that consists of contributions from many unresolvable scatterers that must be treated as random due to lack of knowledge. The nature of the clutter echoes makes it unlikely that bats having to deal with complex environments rely heavily on three-dimensional models of their surroundings and deterministic templates.

Hence, bats must have evolved sensing paradigms to ensure that the clutter echoes contain the relevant sensory information and that this information can be extracted. Coupling between sensing and actuation could very well play a critical role in this. Hence, robotics might be of pivotal importance in replicating the skills of bats in sensing and navigating their environments. Similarly, the deep-learning revolution could bring a previously unavailable ability to extract complex patterns from data to bear on the problem of extracting insight from clutter echoes. Taken together, insights from these approaches could lead to novel acoustics-based paradigms for obtaining relevant sensory information on complex environment in a direct and highly parsimonious manner. These approaches could then enable autonomous robots that can learn to navigate new environments in a fast and highly efficient manner and transform the use of autonomous systems in outdoor tasks.

Biomimetic robots designed to reproduce the (a) biosonar sensing and (b) flapping-flight capabilities of bats. Design renderings by Zhengsheng Lu (a) and Adam Carmody (b).

As pilot demonstration for this approach, we present a twin pair of bioinspired robots, one to mimic the biosonar sensing abilities of bats and the other to mimic the flapping flight of the animals. The biosonar robot has been used successfully to identify locations and find passageways in complex, natural environments. To accomplish this, the biomimetic sonar has been integrated with deep-learning analysis of clutter echoes. The flapping-flight line of biomimetic robots has just started to reproduce some of the many degrees of freedom in the wing kinematics of bats. Ultimately, the two robots are to be integrated into a single system to investigate the coupling of biosonar sensing and flight.

The Evolution of Bat Robots: A Spooky Tale of Echo Location

As Halloween approaches, it’s the perfect time to dive into the mysterious world of bat robots in this Acoustics Today article, “The Evolution of Bat Robots.” The ability of bats to navigate their environment using ultrasound has fascinated scientists for decades, and the mystery of how they process this information has drawn researchers from various fields. It’s no wonder that engineers have been lured into this world, attempting to replicate the biosonar capabilities of bats through a variety of “bat robots.”

Despite decades of research, the intricacies of bat biosonar remain mostly uncharted. Continuous advancements in recording and data analytics technologies promise to unlock more insights into the world of bat robots. These insights will likely drive further evolution in the field. Researchers are on the cusp of developing more integrated systems that combine encoding and extraction of sensory information. These mechanical marvels, inspired by the eerie elegance of bats, may hold the key to autonomous drones capable of navigating the dark forests, just like their natural counterparts.

The Acoustics Today article weaves together a captivating story of technological evolution, highlighting the challenges, breakthroughs, and intriguing possibilities that lie ahead. If you’re curious about how bats’ extraordinary biosonar abilities are inspiring cutting-edge drones and robotic systems, read the full article for free at AcousticsToday.org. It’s a journey that promises to leave you in awe of both nature and human ingenuity. Happy Halloween!

AT Winter 2020 cover - bat robots

2pAB8 – Blind as a bat? Evidence suggests bats use vision to supplement echolocation in presence of ambient light

Kathryn A. McGowan – kmcgowan01@saintmarys.edu
Saint Mary’s College
Le Mans Hall, 149
Notre Dame, IN 46556

Presented Tuesday afternoon, November 6, 2018
176th ASA Meeting, Victoria, British Columbia

Bats use echolocation, or biological sonar, to make an auditory picture of their environment when foraging and avoiding obstacles in flight (1). To echolocate, bats emit a loud, high-pitched sound using their mouth or nose. The sound bounces off an object and returns to the bat as an echo, providing each individual with information about the object characteristics and location. While echolocation allows for the detection and discrimination of targets, the high-pitched frequency sounds that bats emit when echolocating provide a limited range of information (2). Despite being known for flying at night, some bats spend only a part of their time flying in complete darkness, suggesting that they may also rely on vision to supplement their echolocation in environments that have more light (2, 3). Previous studies have demonstrated that vision in bats influences flight behavior, which suggests bats may combine vision and echolocation to sense their environment (2). It is, therefore, accepted that bats are not blind, as the common phrase suggests, but little is known about how vision influences the way bats use echolocation.

Figure 1. Swarm of Brazilian free-tailed bats flying during daylight hours after emergence. Photo Credit – Dr. Laura Kloepper, 2018

The Brazilian free-tailed bat migrates annually from Mexico to form large maternal colonies in caves in the Southwestern United States (2). These bats forage for insects in flight and emerge from the cave in groups of thousands for nightly foraging. The bats return to the cave in the early hours of the morning, requiring them to navigate back to their complex cave environment across a vast, open landscape. This reentry occurs across periods of complete darkness as well as early morning hours when ambient light is present. This suggests that bats have the option of using both echolocation and visual cues to navigate their environment in hours of daylight. Our research addresses how bats change their echolocation calls from an open environment to the more complex cave edge environment, and how the presence of daylight may influence their level of echolocation when accomplishing this feat.

bat echolocation

Figure 2. Spectrogram image of a sequence of bat echolocation calls recorded at the cave environment.

Compared to the calls used over a vast landscape, bats at the cave edge used more complex calls that gathered more precise information about that environment. During hours of daylight, however, these calls collected less precise information than hours of darkness. As less information was gathered acoustically by bats during daylight hours, it is likely that bats are getting information from visual cues once daybreak occurs. This supplementing of vision for echolocation indicates that despite what the phrases say, bats are not blind.

Video 1. Bats emerging for foraging during early dusk.

  1. Moss, C. F., & Surlykke, A. 2010. Probing the natural scene by echolocation in bats. Frontiers in Behavioral Neuroscience 4: 33.
  2. Mistry, S. 1990. Characteristics of the visually guided escape response of the Mexican free-tailed bat Tadarida Brasiliensis Animal Behavior 39: 314-320.
  3. Davis, W.H., Barbour, R.W. 1965. The use of vision in flight by the bat Myotis sodalis. The American Midland Naturalist 74: 497–499.