How does a bat echolocate, and what happens if it loses its hearing?

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1. 1

   Animal echolocation (Wikipedia)

   WikipediaPublished Oct 15, 2026Checked Oct 17, 2026

   “Echolocation, also called bio sonar, is a biological active sonar used by several animal groups, both in the air and underwater. Echolocating animals emit calls and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation, foraging, and hunting prey. Echolocation calls can be frequency modulated (FM, varying in pitch during the call) or constant frequency (CF). FM offers precise range discrimination to localize the prey, at the cost of reduced operational range. CF allows both the prey's velocity and its movements to be detected by means of the Doppler effect. FM may be best for close, cluttered environments, while CF may be better in open environments or for hunting while perched. Echolocating animals include mammals, especially odontocetes (toothed whales) and some bat species, and, using simpler forms, species in other groups such as shrews. A few bird species in two cave-dwelling bird groups echolocate, namely cave swiftlets and the oilbird. Some prey animals that are hunted by echolocating bats take active countermeasures to avoid capture.”

2. 2

   Rapid sensorimotor adaptation to auditory midbrain silencing in free-flying bats.

   Current biology : CB (Diebold et al.)Published Nov 15, 2024Checked Oct 17, 2026

   “Bats were trained to navigate through one of three open windows in a curtain to obtain a food reward, while their echolocation and flight behaviors were quantified with synchronized ultrasound microphone and stereo video recordings. Under control conditions, bats reliably steered through the open window, only occasionally contacting the curtain edge. Suppressing IC excitatory activity elevated hearing thresholds, disrupted overall performance in the task, increased the frequency of curtain contact, and led to striking compensatory sensorimotor adjustments. DREADDs-treated bats modified flight trajectories to maximize returning echo information and adjusted sonar call design to boost detection of obstacles. Sensorimotor adaptations appeared immediately and did not change over successive trials, suggesting that these behavioral adaptations are mediated through existing neural circuitry. Our findings highlight the remarkable rapid adaptive strategies bats employ to compensate for internal sensory interruptions to effectively navigate their environments.”

3. 3

   Resistance to age-related hearing loss in the echolocating big brown bat (Eptesicus fuscus).

   Proceedings. Biological sciences (Capshaw et al.)Published Nov 6, 2024Checked Oct 17, 2026

   “Many echolocating bats exhibit exceptional longevity and rely on acoustic behaviours for survival to old age; however, relatively little is known about the ageing bat auditory system. In this study, we used DNA methylation to estimate the ages of wild-caught big brown bats (Eptesicus fuscus) and measured hearing sensitivity in young and ageing bats using auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). We found no evidence for hearing deficits in bats up to 12.5 years of age, demonstrated by comparable thresholds and similar ABR and DPOAE amplitudes across age groups. We additionally found no significant histological evidence for cochlear ageing, with similar hair cell counts, afferent and efferent innervation patterns in young and ageing bats. Here, we demonstrate that big brown bats show minimal evidence for age-related hearing loss and therefore represent informative models for investigating mechanisms that may preserve hearing function over a long lifetime.”

4. 4

   Simulated target search by bats using biomimetic SCAT biosonar model.

   Frontiers in computational neuroscience (Simmons et al.)Published Apr 8, 2026Checked Oct 17, 2026

   “Bats perceive target distance by measuring the time delay between the outgoing pulse and the returning echo. Acuity of this delay perception depends on the frequency content of echoes and the associated microsecond-level coherence between neural representations of the 1st and 2nd harmonic frequencies. Bats perceive target shape by estimating differences in the delay of mini-echoes from different reflecting points, or glints, within the target. A matched-filter receiver would register glints as prominent peaks in the pulse-echo cross-correlation output, but in bats the overlapping glint reflections mix together to create echo interference patterns that are transposed back into delay estimates. The process is modeled as spectrogram correlation and transformation (SCAT). The first, nearest glint is registered by echo delay itself, but subsequent glints are extracted from the nulls in the interference spectrum. Here, the SCAT receiver was evaluated for its ability to locate targets with a specific glint spacing in the 2D range/cross-range plane while rejecting other targets with larger or smaller spacings.”

5. 5

   In-flight brainstem responses highlight the encoding of self-emitted echolocation calls in bats.

   Proceedings. Biological sciences (Tarnovsky et al.)Published Feb 1, 2026Checked Oct 17, 2026

   “In this study, we introduce a non-invasive method for recording auditory brainstem responses (ABRs) in awake, flying big brown bats (Eptesicus fuscus). Using a custom 3D-printed harness that enables sustained in-place flight, we simultaneously recorded electroencephalographic and acoustic signals from freely vocalizing animals. Self-emitted echolocation calls reliably evoked ABRs, including a distinct pre-auditory wave that occurred before call onset and is probably associated with motor command generation. We were able to extract single-trial individual ABR patterns, which revealed significant correlations between specific acoustic properties of the calls and both ABR amplitude and latency. These findings demonstrate that, despite the suggested peripheral attenuation of self-emitted echolocation calls, the bat auditory system dynamically encodes the characteristics of outgoing vocalizations, with information extraction occurring as early as the brainstem. Our approach offers an effective framework for investigating sensory-motor integration in actively behaving animals.”

6. 6

   First come, first served: neuronal processing of multi-echo streams in the auditory cortex of echolocating bats.

   The Journal of experimental biology (Beetz et al.)Published May 28, 2026Checked Oct 17, 2026

   “In that study, the leading echo was typically the most intense, leaving it unclear whether the echo selectivity was due to echo order or echo level. Here, we recorded from the auditory cortex of anaesthetized Carollia perspicillata, while stimulating the bats with echolocation sequences that contained echo cascades either with echo levels that were equally intense or where the leading echo was less intense than the lagging ones. Our results demonstrate that the echo level has only minor effects on neural processing and that the echo selectivity is mostly caused by the echo order. These results go in line with the neural time window of sensation hypothesis, proposed by Roverud and Grinnell. Whenever the bat hears a pulse, a neural time window opens, and any subsequent high-frequency signal within the spectral range of that pulse is by default classified as an echo, thereby closing the sensation window. This mechanism renders large parts of the cortex less responsive to distant objects, regardless of the echo intensity they produced.”