Intra- and Interspecific Effects on Spatio-Temporal Behavior of Common Commensal Rodent Species.

Commensal rodent species such as roof rats (Rattus rattus), brown rats (Rattus norvegicus), and house mice (Mus musculus) show various ecological and behavioral adaptations to the commensal environment. Where they live in close proximity to humans, they damage infrastructure, contaminate stored goods, and can transmit zoonotic pathogens. Identification of patterns and drivers of movements of these species helps to understand interactions among them as well as interaction with pathogens, humans, and livestock. Using a novel Bluetooth logger system, contact data and rodent movement patterns were recorded in the pig farm environment with unprecedented spatial resolution. There were interspecific differences between roof rat, brown rat, and house mouse in temporal activity, home range size, and movements between individual stable buildings. Rat species showed more nocturnal activity and occupied larger home range areas than co-occurring house mice, which, however, travelled significantly longer distances per hour. All investigated species almost never moved between the interiors of different buildings, but movements within and around buildings were frequent. Intraspecific effects such as sex and body weight were restricted to the effects of body weight on core home ranges (all species) and distance moved per hour (roof rats) as well as more movement between buildings in male versus female brown rats. Commensal rodent species reacted differently to the farm environment, probably to avoid resource competition and to support co-existence. Identifying movement patterns and contact points between rodents and livestock contributes to a better understanding of possible transmission routes of rodent-borne pathogens in livestock farming.