The nature and strength of social motivations in young farmed silver fox vixens (Vulpes vulpes).

摘要

To investigate the strength of social motivation and the motives underlying social contact in farmed silver foxes (Vulpes vulpes), we housed six young vixens continuously in a closed economy operant apparatus and measured their 'maximum price paid' when required to perform a task to obtain unrestricted social contact or food (a 'yardstick' resource). In the former trials, vixens of the same-age and origin acted as stimulus animals (N=6), and both test and stimulus foxes could decide their own visit durations to a shared compartment. Their motives for visiting this 'social compartment' were examined by recording their behaviour during social contact. When access was almost free (a baseline fixed ratio schedule of 1) the test vixens visited the stimulus fox 30.3+or-4.3 times and spent 45% of the time together per 24 h. The stimulus foxes spent on average 80% per 24 h in the shared compartment and visited this cage 40.7+or-9.6 times per 24 h. When higher costs were imposed, the test vixens proved willing to pay to access the stimulus vixens and the average maximum price paid for contact was 38.3+or-8.3% of the price paid for food when hungry. During the time spent together, the stimulus foxes made use of their opportunity to leave the cage, on average 1.43+or-0.20 times per visit. The behaviour recordings showed that during initial encounters the vixens would fight to establish dominance, and in four of the pairs the test subject emerged as the dominant individual. However, during subsequent interactions, no serious aggression was recorded and social behaviour was characterised by higher levels of sniffing and grooming (23.7+or-4.3 times/h), play signals (10.5+or-4.1 times/h) and agonistic displays (5.5+or-2.5 times/h). Not all of the time together was used for social interaction and during the observation period, the vixens allocated 33.1+or-6.9% of the time to synchronous resting. We conclude that young silver fox vixens were motivated for social contact, and that this contact was beneficial for welfare due to the low level of aggression and the occurrence of grooming and play.