Variation in behavioural responses of ewes towards predator-related stimuli

Thirty-two groups of six sheep, classified into three breed categories acco rding to their weight class (L: light, one breed (n = 7); M: medium light, two breeds (n = 10); H: heavy, three breeds (n = 15)) were tested for antip redatory behaviour towards seven stimulus regimes. Tests were performed on 2-5-years-old ewes with lambs inside standardised and fenced home pastures. Stimulus regimes were: man in rain poncho, trolley, ball on trolley (blind stimuli), stuffed wolverine on trolley, stuffed lynx on trolley, stuffed b ear on trolley, and man in rain poncho with a dog on leash (carnivore stimu li). The L breed showed the longest recovery time, the longest Right distan ce and the tightest flocking behaviour. Significant regressions indicate th at then were negative linear relationships between sheep weight and recover y time and between sheep weight and Right distance. Carnivore stimuli cause d longer recovery times (P < 0.001) and longer Right distances (P < 0.001) than the blind stimuli. Our results confirm the hypothesis that lighter she ep breeds display stronger antipredatory reactions than heavier breeds. (C) 2001 Elsevier Science B.V. All rights reserved.