When do you scratch that itch? The relative impact of different factors on scratching depends on the selection of time scale and timing

In their interesting article, Duboscq et al. (2016) used behavioural data to examine equitably a range of hypotheses on the factors that may cause scratching variations in their wild group of Japanese macaque (Macaca fuscata fuscata). They concluded that the animals scratched ‘primarily because of an immune/stimulus itch, possibly triggered by ectoparasite bites/movements’ but did not exclude that other factors may have a secondary role. In this commentary we explain why, in our opinion, the definition of the primary and secondary role of different factors, even within the same group and period, is not absolute but rather time scale and timing dependent.