How Do Scientists Count Pangolins? Population Survey Methods Explained

Counting pangolins is one of the hardest problems in wildlife conservation. These solitary, nocturnal mammals live at naturally low densities, spend their days hidden underground or in tree hollows, and leave few traces that untrained eyes would recognise. Unlike elephants counted from aircraft or wildebeest filmed crossing rivers in their thousands, pangolins demand entirely different census approaches.

Understanding how many pangolins remain — and where — is fundamental to protecting them. Without reliable population baselines, conservationists cannot measure the impact of poaching, assess whether anti-trafficking efforts are working, or identify priority areas for habitat protection. Yet for all eight pangolin species, population data remains thin. The IUCN classifies several populations as data-deficient, and no species has a comprehensive continent-wide or range-wide census.

Researchers have responded by developing and refining a toolkit of indirect survey methods, each suited to different habitats, budgets, and research questions. Here is how scientists are tackling one of conservation biology's most challenging counting problems.

Sign Surveys: Reading the Landscape

The oldest and most accessible method is the sign survey — walking transects through pangolin habitat and recording physical evidence of their presence. For ground-dwelling species like Temminck's ground pangolin (Smutsia temminckii) in South Africa, surveyors look for characteristic digging marks at termite mounds, distinctive three-toed tracks in soft soil, buried scat deposits, and freshly excavated burrow entrances.

Sign surveys are inexpensive and can cover large areas quickly, but they have significant limitations. Detection probability varies with soil type, vegetation density, weather conditions, and surveyor experience. A recent rain can wash away tracks. Dense bush can conceal burrow entrances. And the mere presence of signs does not confirm how many individual pangolins are responsible — one active pangolin may use dozens of burrows across its home range.

Despite these challenges, sign surveys remain a critical baseline tool, especially in remote regions where deploying electronic equipment is impractical. When combined with occupancy modelling — statistical frameworks that account for imperfect detection — sign data can yield useful estimates of where pangolins persist and where they have disappeared.

Camera Trap Surveys: Eyes in the Bush

Camera traps have transformed pangolin monitoring over the past decade. Motion-activated infrared cameras deployed along trails, near termite mounds, and especially at burrow entrances can capture images of pangolins without any human disturbance. Because pangolins are nocturnal, infrared-triggered cameras are ideally suited to recording their activity.

Research on giant pangolins (Smutsia gigantea) in Central Africa has shown that targeting cameras at known burrow sites dramatically improves detection rates compared to random placement. A study published in the journal Oryx found that burrow-targeted deployments outperformed trail-based and random grid designs, yielding more pangolin captures per camera-night.

Camera Trap Distance Sampling

Standard camera trap surveys tell researchers that pangolins are present, but estimating actual population density requires more sophisticated analysis. Camera trap distance sampling (CTDS) applies statistical distance-sampling theory to camera data. By measuring the distance between detected animals and the camera, and modelling how detection probability declines with distance, researchers can estimate the density of pangolins across a survey area — even when individual animals cannot be told apart.

This is particularly valuable for pangolins because, unlike leopards with unique spot patterns or rhinos with distinct horn shapes, most pangolins of the same species look identical in camera trap images. CTDS bypasses the need for individual identification, making it one of the most promising population estimation techniques for unmarked cryptic species.

Local Ecological Knowledge: Surveying People, Not Just Wildlife

In many parts of Africa and Asia, local communities have lived alongside pangolins for generations. They know where pangolins are found, how frequently they are encountered, and whether sightings have increased or decreased over time. Structured surveys that capture this local ecological knowledge (LEK) have become an important complement to field-based methods.

LEK surveys use semi-structured questionnaires administered to randomly selected community members. Respondents are asked about pangolin sighting frequency, habitat associations, seasonal patterns, and perceived population trends. This information is then analysed using occupancy or regression models to estimate population persistence across landscapes.

In Benin, researchers used LEK data from multiple localities to model population extirpation rates for white-bellied and giant pangolins. The models identified landscape change, human pressure, and distance from protected areas as key predictors of whether pangolins had disappeared from a given location.

LEK is especially valuable for surveying large geographic regions where deploying camera traps at every site would be prohibitively expensive. It can rapidly identify areas where pangolins still persist, guiding where to focus more intensive field surveys. However, LEK data must be interpreted carefully — recall bias, cultural factors, and changing land use patterns can all influence responses.

Genetic Methods and Environmental DNA

Molecular techniques are opening new frontiers in pangolin population assessment. DNA can be extracted from pangolin scat, shed scales found near burrows, and confiscated scales from trafficking seizures. Genetic analysis can confirm species identity, reveal population structure and connectivity, estimate genetic diversity, and even approximate effective population size.

Non-Invasive Genetic Sampling

Scat-based genetic surveys are particularly promising. Researchers in Nepal and the Congo Basin have successfully isolated DNA from pangolin droppings, generating mitochondrial sequences that distinguish species and, with microsatellite markers, can identify individuals. When combined with spatial capture-recapture models, individual genetic profiles from scat allow researchers to estimate population density without ever seeing — let alone capturing — a pangolin.

Environmental DNA (eDNA)

Environmental DNA monitoring takes non-invasive sampling a step further. Animals constantly shed DNA into their environment through skin cells, saliva, urine, and faeces. By collecting soil samples from around burrow entrances or wallowing sites and analysing them for pangolin DNA, researchers can confirm species presence at a site. While eDNA is already widely used for aquatic species monitoring, its application to terrestrial mammals like pangolins is still emerging. Early results suggest it could become a cost-effective screening tool for identifying occupied habitat across large areas.

Mark-Recapture and Individual Identification

For populations where researchers can identify individual pangolins, mark-recapture methods provide some of the most robust density estimates available. The Pangolin Universal Notching System — a standardised method of drilling small holes in the non-vascular tips of dorsal scales — allows field workers to recognise recaptured individuals without electronic tags. The technique is low-cost, requires minimal training, and does not harm the animal.

When combined with camera trap surveys, notched pangolins that are photographed can be identified in subsequent sampling sessions. The ratio of marked to unmarked animals in recapture data feeds directly into statistical models that estimate total population size — a classic application of the Lincoln-Petersen method adapted for a modern conservation challenge.

Combining Methods: The Multi-Tool Approach

No single survey method is sufficient for pangolins. Each technique has strengths and blind spots, and the most informative population assessments integrate multiple approaches. A typical modern pangolin survey programme might combine:

• LEK surveys to rapidly identify areas of pangolin persistence across a large region
• Sign surveys and camera traps at priority sites to confirm presence and estimate relative abundance
• Camera trap distance sampling to generate density estimates without individual identification
• Genetic sampling from scat and scales to assess population structure and connectivity
• Mark-recapture at intensively studied sites for calibrating density estimates

The IUCN Pangolin Specialist Group's monitoring guidance document explicitly recommends this integrated approach, recognising that reliable population data requires triangulation from multiple independent data sources.

The South African Context

In South Africa, Temminck's ground pangolin is listed as Vulnerable. Population monitoring is concentrated in the Limpopo, North West, and KwaZulu-Natal provinces, where conservation organisations, private game reserves, and the African Pangolin Working Group collaborate on sighting databases, camera trap networks, and rehabilitation-release monitoring.

South Africa benefits from relatively well-resourced protected areas and a network of trained field rangers, making it one of the better-monitored range states. Yet even here, the total population of Temminck's ground pangolin is not precisely known. Estimates remain extrapolations from local density studies, underscoring the need for continued investment in survey infrastructure.

The 2025 Namibian National Species Management Plan and the 2026 West Africa Regional Pangolin Conservation Action Plan both prioritise standardised population monitoring — signals that range states are increasingly recognising survey methodology as a conservation priority, not just an academic exercise.

Looking Ahead

Advances in technology are steadily improving what is possible. AI-powered image recognition is beginning to automate the classification of camera trap photos, reducing the human labour bottleneck. Miniaturised GPS tags and satellite-connected camera traps can transmit data in near-real-time from remote locations. And as eDNA techniques mature for terrestrial applications, the cost of confirming pangolin presence at a site may drop dramatically.

But technology alone will not solve the pangolin counting problem. Sustained investment in field capacity, community engagement, and cross-border data sharing will determine whether the next decade delivers the population baselines that pangolin conservation urgently needs. Every survey, every camera trap night, and every scat sample collected brings researchers closer to answering the fundamental question: how many pangolins are left?