Abstract: A computer implemented method for distinguishing between animals depicted in one or more images, based upon one or more taxonomic groups. The method comprises receiving image data comprising a plurality of parts, each part depicting a respective animal, determining one or more spectral properties of at least some pixels of each of the plurality of parts, and allocating each of the plurality parts to one of a plurality of sets based on the determined spectral properties, such that animals depicted in parts allocated to one set belong to a different taxonomic group than animals depicted in parts allocated to a different set.