Research overview: camera-trap distance sampling methodology

Camera-trap distance sampling adapts classical distance-sampling theory to estimate density of unmarked animals from the distances at which they are detected within the camera's field of view. This overview explains how the method models the decline in detection probability with distance and angle, accounts for the proportion of time animals spend in the detection zone via snapshot moments, and thereby estimates density without individual identification or movement-speed inputs. It discusses the practical demands, notably accurate estimation of animal-to-camera distances through calibration markers or photogrammetry, and the assumptions that must hold for valid inference. As one of the leading recognition-free estimators, camera-trap distance sampling is increasingly applied to felids and their prey. The overview compares its data requirements and strengths with the Random Encounter and REST models.