Social anchors: how previous social locations shape current animal movement and habitat selection

Abstract

Memory of past space use is an important factor in habitat selection, but memory of what? The concept of memory captures the geographic spaces that an animal has used in the past. There are, however, competing reasons why animals occupy a given space. Species may occupy space due to particular aspects of their memory. Using integrated step selection analysis, we tested the relative importance of memory: previous use of high forage quality or where social interactions occurred at two temporal scales in caribou (Ranger tarandus). The most important parameter to explain intra-seasonal movement was geographic memory. At the inter-annual scale, caribou more strongly revisited locations with high quality forage and where they had formed dyads with conspecifics. We posit that remembered locations of social fusion can function as social anchors. The effects of memory on movement behaviour depend upon the context, both social and resource-based, and not geographic space alone.