Acoustic Monitoring for Pangolins: Research Methods and Current Gaps

Published 14 June 2026 — alphapanga.com

Acoustic monitoring has transformed wildlife conservation over the past two decades. Passive acoustic monitoring devices — compact digital recorders that can operate unattended for weeks in remote habitat — have been used to survey bat populations, detect poaching gunshots, identify bird species in inaccessible forest canopy, and track whale migration patterns across ocean basins. For pangolins, however, acoustic monitoring presents a fundamentally different challenge: these are among the quietest mammals on earth, and the sounds they produce are so infrequent and context-specific that standard passive acoustic monitoring approaches cannot reliably detect pangolin presence from sound alone.

What Sounds Do Pangolins Make?

Adult pangolins are predominantly silent. Across all eight species, the documented vocalisation repertoire is sparse. The most consistently reported sound is a low-frequency puffing or hissing exhalation produced when a pangolin is alarmed or handled — a threat response analogous to the defensive hissing of many reptiles. This sound is produced at close range, directed at an immediate threat, and would not be detectable beyond a few metres under any field conditions.

Mother-pup communication is the context most likely to yield detectable vocalisations. Pangolin pups produce high-pitched distress calls when separated from their mothers or when handled by humans. These calls are described in rehabilitation records as a series of short, sharp squeaks in the frequency range of 2 to 8 kilohertz — well within the detection range of standard passive acoustic monitors but produced only intermittently and only by young animals. Maternal response vocalisations have been documented in captivity, where mothers emit soft contact calls when reuniting with distressed pups, but these calls are low-amplitude and would be difficult to detect in noisy field environments.

The Ultrasound Question

One significant unknown in pangolin bioacoustics is whether these animals produce ultrasonic signals — sounds above 20 kilohertz, inaudible to humans — for communication or orientation purposes. Many small mammals including shrews, rodents, and bats produce ultrasonic communication signals that serve social bonding, territory marking, and predator alarm functions. Given the pangolin's generally poor visual acuity and its reliance on olfaction and touch as primary senses, ultrasonic communication is a plausible but unstudied hypothesis.

No published study has systematically surveyed pangolins with broadband ultrasonic detectors across a full activity cycle. Captive pangolin facilities would be the most practical setting for such research, but the small number of facilities holding pangolins and the fragility of captive animals have historically made detailed acoustic experiments difficult to conduct without welfare risks. This represents a genuine gap in the basic biology of the order Pholidota.

Passive Acoustic Monitoring: What It Can and Cannot Detect

Passive acoustic monitoring (PAM) devices such as the Wildlife Acoustics Song Meter series and the Open Acoustic Devices AudioMoth are widely deployed in African wildlife habitats for bat and bird surveys. In pangolin habitat, PAM devices may pick up several incidental acoustic signals associated with pangolin activity, but none are specific enough to confirm pangolin presence from sound alone.

Foraging pangolins produce substrate-borne sounds when excavating termite mounds: scraping of claws on hard mound material, dislodgement of mound fragments, and the rustling of leaf litter during locomotion. These sounds are audible to a nearby observer and would register on a sensitive recorder, but they are acoustically indistinguishable from the foraging sounds of many other medium-sized mammals including civets, genets, springhares, and porcupines. Automated species classifiers — machine learning models trained to assign vocalisation recordings to species — do not currently have validated pangolin-specific acoustic signatures to work with.

Camera Trap Integration

The most effective acoustic contribution to pangolin monitoring is the integration of audio recording with motion-triggered camera traps. Camera traps with microphones capture both visual confirmation of species identity and contemporaneous sound, allowing researchers to build a library of pangolin-associated sounds under controlled detection conditions. Over multiple recording seasons, this approach can generate the acoustic reference dataset that would be needed to train an automated pangolin classifier, even if the training process takes years to accumulate sufficient positive examples.

Camera trap audio has already proven useful in distinguishing pangolin visits from other nocturnal mammal visits at artificial feeding sites used in behavioural research, where the distinctive claw-scraping sound on presented termite mound material differs tonally from rodent gnawing or carnivore sniffing. However, this application is specific to managed research environments and does not translate directly to large-scale habitat survey.

Acoustic Technology for Anti-Poaching, Not Species Detection

The most practical current application of acoustic technology in pangolin conservation is not detecting pangolins directly but detecting the human activity that threatens them. Several anti-poaching technologies developed for larger-landscape wildlife crime monitoring are directly relevant to pangolin protection.

Gunshot detection systems — which use networks of acoustic sensors to triangulate the location of firearms discharges in real time — have been trialled in several southern and east African reserves. While poaching of pangolins rarely involves firearms (trapping and hand capture dominate), gunshot detection contributes to overall ranger deployment efficiency in reserves where pangolins coexist with rhinoceros or elephant populations that are also targeted by armed poachers.

More relevant to pangolin-specific enforcement are low-frequency ground-sensor networks and acoustic footstep detection systems. These systems, developed primarily for military perimeter security, can detect and classify human footfall patterns and distinguish them from wildlife movement within a monitored zone. Pilot programmes in Mozambique's Niassa Special Reserve and Zimbabwe's Save Valley Conservancy have demonstrated that acoustic ground sensors can alert rangers to human presence in critical wildlife areas faster than visual patrols. In areas with high pangolin density, such systems could trigger targeted patrol responses during the early night hours when pangolin poaching is most likely to occur.

Ranger Acoustic Tools in the Field

Individual rangers in pangolin-range countries have reported using auditory cues in the field to locate active pangolin foraging sites, though these techniques are informal and unstandardised. The most commonly cited cues are the sound of claw strikes on hard termite mound surfaces, audible from approximately 20 to 30 metres in calm conditions, and the rustling movement pattern of a large animal through dense leaf litter — characterised as slower and more methodical than the movement of similarly sized carnivores.

Training rangers to identify these incidental acoustic signatures has been incorporated into some field skills programmes in southern Africa, particularly for anti-poaching units operating in reserves with confirmed pangolin populations. The approach is analogous to bird-by-ear identification training and relies on experiential exposure rather than technological tools. Its effectiveness is difficult to quantify but is reported by experienced rangers as a meaningful complement to track identification and camera trap monitoring.

Comparative Context: Why Pangolins Are Acoustically Challenging

The contrast with other well-studied taxa illustrates the specific challenge pangolins pose for acoustic approaches. Bats have an entire monitoring discipline built around their ultrasonic echolocation calls, with thousands of published recordings and validated machine learning classifiers for hundreds of species. Birds are similarly accessible: most species produce loud, species-specific vocalisations that passive acoustic monitors can record reliably, and automated identifiers such as BirdNET achieve high species-level accuracy across broad geographic ranges.

Even among mammals, acoustic monitoring is effective for cetaceans (which communicate constantly), elephants (which produce infrasound detectable kilometres away), and great apes (which have rich vocalisation repertoires). Pangolins sit at the extreme quiet end of the mammalian vocalisation spectrum, comparable in acoustic conspicuousness to slow lorises or armadillos — animals for which acoustic monitoring has similarly limited applicability.

Research Priorities

Three research directions would meaningfully advance the acoustic monitoring of pangolins. First, a systematic captive study using broadband (0 to 100 kilohertz) audio recording equipment across multiple individuals in several facilities would either confirm or rule out ultrasonic communication, resolving the most significant unknown in pangolin bioacoustics. Second, a camera-trap-with-audio deployment protocol across a high-density pangolin habitat such as Tswalu Kalahari Reserve or Limpopo National Park would build the first large-scale acoustic reference library for ground pangolin foraging sounds. Third, the integration of machine learning classifiers trained on incidental pangolin-associated sounds — rather than vocalisation-based classifiers — could eventually allow PAM data to contribute to pangolin habitat use assessments, even if species-level confirmation still requires camera or direct observation.

Until that research is completed, acoustic monitoring should be understood as a supplementary tool in the pangolin conservation toolkit: valuable for anti-poaching detection, useful as part of multi-method monitoring arrays, but not capable of standalone pangolin population assessment.

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