MATERNAL INFANTICIDE AND PERIPARTURIENT BEHAVIOR IN FARMED SILVER FOXES VULPES-VULPES

This study aimed at describing and searching for causes of infanticide by farmed silver-fox vixens. Reproduction and periparturient behaviou r were studied in 21 litters of primiparous and 18 litters of multipar ous vixens by video-recording inside the breeding box. Of 54 dead cubs , 41 had been bitten and probably killed. The probability that a cub w ith a primiparous mother would be killed was 37%. Seventeen vixens wer e categorized as infanticidal. Primiparous vixens killed cubs shortly after birth, whereas multiparous ones showed normal maternal behaviour during parturition and killed later. Cubs were not killed more often during working hours. A longitudinal study including nine cub-killers showed that they usually repeated such behaviour in subsequent years. Half of the infanticidal vixens bit off the tails of their offspring p rior to killing them. Dead cubs were treated as prey, often buried und er wool tangles and later eaten, whatever the cause of death. A quanti tative analysis of behaviour was made by instantaneous sampling of 19 vixens (12 infanticidal). Cub-killing vixens and vixens which reproduc ed normally, in general, showed quite similar time-budgets of behaviou r. Cub-killers also groomed cubs as frequently as non-killers, but sto od more often when grooming, and showed more self-grooming and less re sting inside the box during the first day post-partum. Environmental d isturbances or social pathology were considered unlikely to be signifi cant causes of cub-killing on the farm. Although several similarities were found with infanticide in other farm animals, infanticidal vixens did not show severe behavioural abnormalities.