Do different competition strategies affect social preference and behaviour in silver fox vixens (Vulpes vulpes)?

Among mammals, social ranking is generally thought to affect the outcome of disputes over preferred, limited or future resources. Therefore, we should expect individuals’ preference for conspecifics to be affected by their own and other individuals’ competition capacity. Here, we investigated the social preference and behavioural response in farmed silver fox vixens (Vulpes vulpes) towards unfamiliar vixens of different competition capacities, measured by their ability to compete for and defend a limited food resource, in a choice test. We found that low competition capacity vixens spent significantly less time in front of the high competition capacity vixens (2647 ± 600 s) compared to the time they spent in front of the low competition capacity vixens (6041 ± 877 s, P < 0.05). In addition, the low competition capacity vixens spent significantly less time in front of the high competition capacity vixens (2647 ± 600 s) compared to what the high competition capacity vixens did (4215 ± 657 s, P = 0.03). This suggests that low competition capacity vixens perceive high competition capacity vixens as a greater potential threat than high competition capacity vixens do. Time spent in social exploration, resting, sitting and performing aggressive behaviours in front of a stimulus animal were also affected by competition capacity of the foxes. The vixens were also retreating significantly more from the high competition capacity vixens (2 ± 0.8 times) than from the low competition capacity vixens (0.4 ± 0.4 times, P = 0.03), possibly reflecting that the high competition capacity vixens were more offensive than the low competition capacity vixens. Our results contribute to the knowledge of social behaviour in this species, and may have implications for the social housing environment of the farm foxes.