Age-dependent responses to chemosensory cues mediating kin recognition in dogs ( Canis familiaris)

During individually administered 5-min tests conducted in a neutral cage, four age groups ( n = 10) males and 10 females per group) of purebred beagles reacted to bedding from their home cage vs. bedding from another litter of the same age. The 20–24-day-old males and females preferred ( p < 0.05) home cage bedding over strange cage bedding. Those aged 31–36 days or 66–72 days showed no reliable preference for either type of bedding. Among pups aged 52–56 days, the males preferred ( p < 0.05) strange cage bedding, but the females showed no reliable preference. Chemosensory cues are sufficient as mediators of kin recognition in beagles, but their reactions to such cues vary with age-dependent factors, some stemming from changes in the strength of the mother-litter bond. The dogs providing the two types of bedding lived in the same room and on the same diet. Therefore, kin recognition could not have been mediated by different chemosensory cues produced by variations in these environmental factors.