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.

Listening in on the Conversations of Coyotes

Jennifer Schneider – jschneider@lcc.lt

LCC International University
Kretingos 36, KLAIPEDA
KLAIPEDA M., LT-92307
Lithuania

Dustin H. Ranglack
USDA APHIS WS National Wildlife Research Center
Utah Field Station

Popular version of 2pABa2 – A Comparison of the Squeaking Vocalizations of North American Wild Canids
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

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

The Question: Do Coyotes Squeak like Wolves Squeak?
We are all familiar with howls, but how many of us have heard a wolf or a coyote squeak? Squeaks are easy to miss for a number of reasons: one has to be in close proximity to hear them, animals behave differently when humans are around, and squeaks are easy to mistake for birdsong. Wild canids live in family groups and need to communicate during face-to-face interactions. Both gray (Canis lupus) and red wolves (Canis rufus) produce strings of short, quiet, high-frequency squeaks in a variety of friendly contexts. Yet, despite coyotes’ (Canis latrans) close relationship with wolves, this study is the first to systematically examine coyote squeaking vocalizations.

Video Credit: US Department of Agriculture. The male (closest coyote) squeaks several times, followed by the female. The male squeaks again when approaching the camera.

The Setup: Meeting the New Neighbors
To determine whether coyotes squeak we created a social situation to encourage interaction between bonded coyote pairs and their neighbors at the USDA Predator Research Station in Millville, Utah. Three pairs of coyotes were moved into adjacent enclosures and recorded using camera traps and continuous audio recordings. The observations reported here include the first 3.5 hours after release, as the animals explored their new enclosures and interacted through the fence with their neighbors.

Video Credit: US Department of Agriculture. Four coyotes vocalizing at the intersection between enclosures.

The Comparison: How Similar are Coyote Squeaks to Wolf Squeaks?
Coyote squeaks shared many similarities with wolf squeaks:

  • The number of squeaks per vocalization varied greatly (1 – >30).
  • The frequency bandwidth within which coyotes squeaked (3.0-11.0 kHz) was broad, more similar to red wolves (2.7-9.5 kHz) than gray wolves (1.8-6.0 kHz).
  • Squeaks of all three species display a variety of contours, with flat or bump-like shapes being among the most common.
  • Coyote squeaks were shorter, but showed similar frequency ranges to those of gray wolves, and were longer with greater frequency ranges than those of red wolves.
  • Squeaks occur in prosocial contexts such as greeting, friendly approach, play, and during howling sessions.

Like red wolves, coyotes sometimes produced a second, lower-frequency component (0.5-1.6 kHz), or wuh, simultaneously with their squeaks, a phenomena knowns as biphonation. Since we used multiple recorders, we discovered that the wuh did not travel as far as the squeak (Fig. 1). Therefore, the message received by eavesdroppers will be different than the message received by coyotes in the immediate area.

Two spectrograms showing frequency patterns from 0 to 10kHz with distinct vertical bands and intensity variations in purple, red, and orange hues.

Figure 1. Spectogram of a squeak vocalization with biphonations recorded near the vocalizing coyote (top panel) and on the far side of the enclosure (lower panel). The high-frequency squeak was still audible on the far side of the enclosure while the low-frequency wuh was not. To listen click here.

Why it Matters
Coyotes and wolves, being predators, often viewed negatively by humans. However, these animals also mate for life, live in social groups, and even raise young together. Getting a more holistic understanding of the lives of these animals requires listening in on their intimate communication. Squeaking is ubiquitous across North American canid species, despite differences in social structure complexity. Identifying the importance of this vocalization is only the first step. While we can see that squeaking is affiliative in nature, we are still a long-way from unlocking the subtleties of meaning in individual utterances.

Manduca sexta Caterpillars Hear Using Hairs

Sara Aghazadeh – saghaza1@binghamton.edu
Instagram: @saraaghazadeh1016
Department of Mechanical Engineering
Binghamton University (SUNY)
Binghamton, NY, USA

Aishwarya Sriram – asriram@binghamton.edu
Instagram: @sriram.aishwarya
Department of Biological Sciences
Binghamton University (SUNY)
Binghamton, NY, USA

Prof. Carol Miles – cmiles@binghamton.edu
Department of Biological Sciences
Binghamton University (SUNY)
Binghamton, NY, USA

Prof. Ronald Miles – miles@binghamton.edu
Department of Mechanical Engineering
Binghamton University (SUNY)
Binghamton, NY, USA

Popular version of 4pABb3 – The ears of Manduca sexta caterpillars
Presented at the 189th ASA Meeting
Read the abstract at https://eppro02.ativ.me/appinfo.php?page=Session&project=ASAASJ25&id=3982723&server=eppro02.ativ.me

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

The aim of this research is to explore how insects perceive vibration and sound, ultimately mimic these biological strategies to advance the technology of MEMS microphones. Some insects have tympanal membranes for the detection of sound pressure. These include, for example, katydids and crickets that have tympanal membranes on their forelegs, and the fly, Ormia ochracea that has paired tympanal organs on its prothorax. Most insects and spiders that can hear sound use non-tympanal sensors, such as long hairs on bee and mosquito antennae, and slit sensilla hairs in spiders. We are looking at Manduca sexta, tobacco hornworm caterpillars, a common garden pest devouring tobacco plants. This caterpillar can be found devouring tomato plants in your vegetable garden. While it does respond to sound, it is not clear whether it hears by detecting air-borne sound pressure using a tympanal membrane, hears acoustic particle velocity through the use of sensory hairs, or hears through the detection of sound-induced substrate vibration.

In this study, the caterpillars’ behavioral responses to sound were examined using sounds at two different frequencies: a 150 Hz tone, and a 2000 Hz tone. Previous studies have found strong behavioral responses at 150 Hz in tuning curve experiments. By measuring the sound-induced motion of a thoracic hair using laser vibrometry, we have observed a natural resonance of the hair at 2000 Hz. While we don’t normally expect insect hairs to be effective sound detectors at such high frequencies, this observation motivates further examination to look for behavioral responses.

We monitored caterpillars’ behavioral responses to vibrations of the surface the caterpillars were standing on, and to air-borne sound while we recorded the amplitude of the surface vibration. The results revealed that the caterpillars were 10-100 times more responsive to airborne sound than sound-induced vibration of the surface detected by their feet; this confirms that they perceive airborne sound. Our results show that they can hear airborne sound at a low-frequency of 150 Hz and a high-frequency of 2000 Hz.

We investigated whether certain identifiable thoracic and abdominal hairs enable the caterpillars to hear these specific frequencies through a series of experiments with and without the hairs removed. Please watch the video.

The result of the behavioral response comparisons before and after removal of the hairs on each caterpillar showed a greatly reduced ability of the caterpillars to detect sounds without the hairs. This indicates that M.sexta caterpillars use specific hairs located on their abdomen and thorax for detecting airborne sounds at 150 Hz and 2000 Hz. This provides evidence of non-tympanal sound detection in these caterpillars for these specific frequencies.

Ultrasonic Pest Control To Protect Beehives

New technique uses ultrasonic signals that mimic bat calls to deter wax moths from beehives #ASA_ASJ2025 #ASA189

HONOLULU, Dec. 4, 2025 — Bees, and other pollinator species, are dying. Between pesticides, the climate crisis, and habitat loss, bee colonies are becoming weaker, leaving them more vulnerable to parasites like the greater and lesser wax moths. Vulnerable bees have cascading effects on beekeepers and food security in the apiculture industry.

A team of researchers from the University of Strathclyde and Japan’s National Agriculture and Food Research Organization is exploiting the unusual hearing of wax moths to develop a sustainable and efficient pest control technique that does not harm bees.

Lara Díaz García, postdoctoral researcher at the University of Strathclyde, will present her findings Thursday, Dec. 4, at 10:30 a.m. HST as part of the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1-5 in Honolulu, Hawaii.

A female specimen of the greater wax moth (Galleria mellonella) in the middle of tethered flight experiments. Credit: Lara Díaz García

A female specimen of the greater wax moth (Galleria mellonella) in the middle of tethered flight experiments. Credit: Lara Díaz García

Wax moths take advantage of weakened bee colonies, tunneling through the hive and feeding on the honeycomb and bee eggs. Removing infestations is labor-intensive — beekeepers must remove individual frames affected by the infestation and catch any remaining wax moths with sticky traps.

These moths can hear sounds four octaves higher than a human can, and this ultrasonic hearing helps them avoid becoming tasty bat food and hear male moth calls. They tell these calls apart based on the timing of the signal and the loudness of the sound.

By analyzing which patterns of bat echolocation calls elicited a stronger neural response in the moths, the researchers determined the best ultrasonic deterrent. Because bees have no sense of hearing, this pest control mechanism does not harm them.

“The technique can be adapted to different moth species; it would require some work for tuning to the most sensitive range to their particular hearing, and then targeting that range, but once that initial part is done, the technique should be applicable to any other moth species capable of hearing — which is the majority of them,” said Díaz García.

The team also developed a simplified model of the lesser wax moth eardrum, capturing its essential features to explain its directional hearing. They hope to generalize their method for other moth species and to develop a commercial pest control device or acoustic sensors inspired by moth ears.

“Nature is truly impressive and inspiring for technological development,” said Díaz García. “It’s also great to contribute to a very tangible outcome of very real problems that we’re seeing due to the climate crisis.”

Contact:
AIP Media
+1 301-209-3090
media@aip.org

——————— MORE MEETING INFORMATION ——————–

Main Meeting Website: https://acousticalsociety.org/honolulu-2025/
Technical Program: https://eppro02.ativ.me/web/planner.php?id=ASAASJ25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE ACOUSTICAL SOCIETY OF JAPAN
ASJ publishes a monthly journal in Japanese, the Journal of the Acoustical Society of Japan as well as a bimonthly journal in English, Acoustical Science and Technology, which is available online at no cost https://www.jstage.jst.go.jp/browse/ast. These journals include technical papers and review papers. Special issues are occasionally organized and published. The Society also publishes textbooks and reference books to promote acoustics associated with various topics. See https://acoustics.jp/en/.

More Press Releases

Elephant Seals Recognize Their Rivals From Years Prior

Male elephant seals respond to recorded calls of their old rivals, demonstrating lasting familiarity. #ASA_ASJ2025 #ASA189

HONOLULU, Dec. 1, 2025 — How would you react if you overheard the voice of a long-lost friend or old co-worker? Chances are, just the sound of their voice will bring back memories of times you spent together. Humans are not the only animals that can remember the voices of their old acquaintances. Elephant seals, too, can remember the calls of their rivals even a year later.

Caroline Casey, research scientist and adjunct professor at the University of California, Santa Cruz, will present her team’s research on elephant seal memory Monday, Dec. 1, at 2:45 p.m. HST as part of the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1-5 in Honolulu, Hawaii.

A male elephant seal in the middle of a vocalization (NMFS Permit #23188) Credit: Caroline Casey

A male elephant seal in the middle of a vocalization (NMFS Permit #23188) Credit: Caroline Casey

Casey and her team have spent over a decade studying the seals on Año Nuevo Island off the coast of California. They have observed male elephant seals engaging in dominance displays year after year, and it led them to wonder if the seals remembered their past bouts.

“Male elephant seals come back to the exact same breeding location year after year and engage in competitive interactions with a number of familiar individuals,” said Casey. “It would make sense, then, that they would retain some memory of past rivals over multiple seasons.”

To test this, the team would find a male seal returning to the island at the start of the mating season and play recorded calls from his old rivals.

“When males heard their most familiar dominant rival from last year, they tended to orient faster, exhibit a faster posture change, and often would retreat from the speaker,” said Casey. “Their responses were less severe when they were presented with their subordinate rival from the previous season, and sometimes they would even approach the speaker.”

They also played calls recorded at other colonies, observing that these unfamiliar calls elicited a much smaller response from the seals. This proved that the seals were not just responding to random strangers but actually recognizing and remembering individuals they had met the year prior.

The researchers are continuing to study elephant seal reproductive behaviors.

“Right now, we are working on a project evaluating the traits that lead to eventual reproductive success in male elephant seals,” said Casey. “Essentially, what does it take to become an alpha seal? We are measuring lots of different aspects of behavior and physiology and linking it to true reproductive success in this species.”

Contact:
AIP Media
+1 301-209-3090
media@aip.org

——————— MORE MEETING INFORMATION ——————–

Main Meeting Website: https://acousticalsociety.org/honolulu-2025/
Technical Program: https://eppro02.ativ.me/web/planner.php?id=ASAASJ25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE ACOUSTICAL SOCIETY OF JAPAN
ASJ publishes a monthly journal in Japanese, the Journal of the Acoustical Society of Japan as well as a bimonthly journal in English, Acoustical Science and Technology, which is available online at no cost https://www.jstage.jst.go.jp/browse/ast. These journals include technical papers and review papers. Special issues are occasionally organized and published. The Society also publishes textbooks and reference books to promote acoustics associated with various topics. See https://acoustics.jp/en/.

More Press Releases

Sounding Out Coral Larval Settlements #ASA188

Sounding Out Coral Larval Settlements #ASA188

Coral larvae are attracted to areas with other healthy coral structures, using cues like sound to seek them out.

Media Contact:
AIP Media
301-209-3090
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coral larvae

Natalie Levy, a post-doctoral researcher, counts settled coral larvae with an ultraviolet light on the synthetically coated microhabitat structures. Credit: O. Boulais

NEW ORLEANS, May 22, 2025 – Coral reefs are vital to marine biodiversity, but their livelihood is under threat due to climate instability and the impacts of human activities.

Rehabilitating marine environments requires innovative solutions. Océane Boulais, a doctoral student at the Scripps Institution of Oceanography, studies one of these potential solutions: the impacts of acoustics on coral larval recruitment and settlement.

After spawning, coral larvae drift or swim through the water column, seeking suitable sites to find a home to attach to along the ocean floor.

“Multiple chemical compounds have already been identified as environmental cues that stimulate this settling behavior, presumably by indicating to the larvae when other successful-settled coral structures are nearby,” said Boulais. “A growing body of evidence over the past 20 years is also finding that sound may be another such cue.”

Healthy reefs are acoustically rich environments, filled with fish croaks and shrimp snaps. Boulais and their collaborators mimicked these sound environments to study the effects of sounds on 19 artificial coral settlement modules placed in Kāneʻohe Bay, Oahu, Hawaii. The researchers recorded audio near a vibrant reef, which they replayed at various distances from their artificial microhabitats. The artificial microhabitats were coated with a bacteria designed to induce larval settlement, creating a suitable habitat for attracting coral larvae.

Boulais will present details on their findings about the impacts sound has on coral larvae Thursday, May 22, at 9:20 a.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23. Notably, there were significant increases in coral settlement close to the speakers.

The researchers are planning an additional data deployment in the summer of 2025. Boulais said they hope to ultimately develop scalable strategies to study larger reef structures with audiovisual remote sensing tools, using low-cost cameras for continuously monitoring the reef’s biodiversity.

“Innovative, interdisciplinary approaches — combining science, technology, and creativity — can offer powerful solutions to pressing environmental challenges like coral reef degradation,” Boulais said. “Ultimately, I hope this research inspires both urgency and hope for the future of coral reefs.”

——————— MORE MEETING INFORMATION ———————
Main Meeting Website: https://acousticalsociety.org/new-orleans-2025/
Technical Program: https://eppro01.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASAICA25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE INTERNATIONAL COMMISSION FOR ACOUSTICS
The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.