Breeding status affects territorial behaviour to simulated intruders in captive wolves

Grey wolves ( Canis lupus ) rely on olfaction to communicate and acquire information about their environment. Olfactory signals delivered via urine, faeces, and glandular secretions, serve critical functions in reproduction, social interactions, and territorial defence. We studied the role of olfactory signals in mediating inter-pack conflict, a leading cause of mortality in free-ranging wolves, by exposing zoo-housed wolves to the scent of an unfamiliar individual, mimicking an intruder. We predicted breeding adults to exhibit higher investigatory and territorial behaviours, accompanied by an increased patrol effort in response to this simulated intruder than other individuals due to their dependence on territorial integrity and reproductive investment. Consistent with this prediction, breeders displayed significantly higher rates of investigatory, territorial and locomotor behaviours to conspecific than heterospecific urine than non-breeders. These findings highlight the specialised role that breeders play in wolf packs, particularly in relation to territorial defence, and demonstrate the deeply conserved patterns of territorial behaviours in wolves, even in populations that have been living under human care for a long time. Our findings have implications for theories of mammalian olfactory signalling and potential applications for conservation, including scent-based bio-fencing, to reduce human–wildlife conflicts.