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A camera trap is a camera that records wildlife automatically, triggered by heat or motion sensors, so that animals can be documented without an observer present. This guide explains how camera traps work, what a field study needs to plan, and how the images become structured research data through two open standards.
Who uses it: wildlife biologists, ecologists and conservation researchers, along with the data managers who archive their records.
What a camera trap is
A camera trap is a remotely placed camera that records wildlife using heat or motion sensors (Camera Trap Metadata Standard paper, PMC5267527). It is particularly useful for studying nocturnal, low-density and human-avoiding mammals, which are hard to observe directly. Camera trapping is one of the field methods used across wildlife biology, zoology and conservation biology.
How a camera trap works
The camera stays idle until its sensor detects heat or movement, then it captures an image. Modern camera traps are increasingly able to capture a burst of photos every time they are triggered (PMC5267527). Because one animal passing the camera produces several pictures, research data standards group those pictures into sequences rather than treating each file as an independent observation.
Types and variants
The sources read for this guide describe camera traps only at the level of how they are triggered and how many pictures they capture, so the table below is limited to those distinctions. It does not rank brands or models.
| Variant | Typical use | Key difference |
|---|---|---|
| Heat- or motion-triggered camera | Documenting nocturnal, low-density and human-avoiding mammals without an observer present | A heat or motion sensor starts recording (PMC5267527) |
| Burst-capable camera | Capturing several pictures per passing animal | Modern camera traps are increasingly able to capture a burst of photos at each trigger, which is why data standards group images into sequences (PMC5267527) |
Source: Camera Trap Metadata Standard paper, PMC5267527, read 2026-11-08. The sources read do not give selection criteria or equipment handling guidance, so this guide does not offer them; consult the manufacturer’s documentation and your institution’s field-safety procedures for hardware choice and handling.
Study design: how much effort is enough
Effort is a design decision, not an afterthought. The Research Institute for Nature and Forest (INBO, Flanders) reports on camera-trap use in wildlife management. Its summary gives these figures:
| Design element | Figure reported by INBO | Context |
|---|---|---|
| Number of camera locations | At least 35 | Grid-based survey for estimating presence and density |
| Deployment duration | About 3 to 5 weeks | Same survey design |
| Rare or shy species | Greater effort required | The INBO summary states that such species need more effort than the baseline design |
Source: INBO, Gebruik van cameravallen in het kader van wildbeheer (publication abstract), read 2026-11-08. The figures describe that publication’s recommended design and are not universal thresholds; a project’s own species, habitat and question determine its sampling plan.
From images to data: two open standards
An archive of unlabelled photos is hard to reuse. Two community standards define how camera-trap records should be described. Both build on the idea that the unit of record is a placement of a camera in space and time, not just an image file.
| Standard | Structure | Key definitions |
|---|---|---|
| Camera Trap Metadata Standard (CTMS) | Hierarchy of four levels (Project, Deployment, Image Sequence, Image) with 35 fields | A deployment is “a unique placement of a camera trap in space and time”. An image sequence is all pictures within 60 seconds of the previous picture, unless the project sets another interval. Camera and location identifiers are tracked separately, so gaps such as battery failures can be captured. It is designed to work with Darwin Core, FGDC, EML and Audubon Core. |
| Camtrap DP | A Frictionless Data Package with three tables: deployments.csv, media.csv, observations.csv | Deployments are camera trap placements; media are the media files recorded during deployments; observations are derived from the media. It is described as a community-developed data exchange format and is managed by the Machine Observations Interest Group of TDWG. |
Sources: CTMS paper (PMC5267527) and the Camtrap DP specification (camtrap-dp.tdwg.org), both read 2026-11-08. For general background see the dictionary entries for metadata and Darwin Core, and plan how these records will be stored and shared in a data management plan.
Common mistakes
- Recording only images. Without deployment records (where and when each camera was active), absences cannot be interpreted. CTMS and Camtrap DP both make the deployment a first-class record.
- Merging camera and location identity. CTMS tracks camera and location IDs separately so that gaps, such as a battery failure, are visible rather than silently lost.
- Treating every burst frame as an independent detection. Bursts are grouped into image sequences (60 seconds by default in CTMS) before counting.
- Under-sizing the survey. The INBO design figures above are a reminder that density estimation and rare-species work need many locations and weeks of effort.
FAQ
What is a camera trap used for?
It documents wildlife without an observer present, which suits nocturnal, low-density and human-avoiding mammals (PMC5267527).
How do camera traps trigger?
They use heat or motion sensors to start recording (PMC5267527).
What is a deployment?
In CTMS, a deployment is a unique placement of a camera trap in space and time.
Which data format should camera-trap data use?
Two open options are the Camera Trap Metadata Standard and Camtrap DP; check which one your repository or funder expects.
Sources
- Camera Trap Metadata Standard paper, PMC5267527: https://pmc.ncbi.nlm.nih.gov/articles/PMC5267527/ (read 2026-11-08)
- Camtrap DP, TDWG: https://camtrap-dp.tdwg.org/ (read 2026-11-08)
- INBO, Gebruik van cameravallen in het kader van wildbeheer: https://www.vlaanderen.be/inbo/en-GB/publications/gebruik-van-cameravallen-in-het-kader-van-wildbeheer (read 2026-11-08)
