子羊の母羊識別時における視覚・聴覚・嗅覚の役割

Abstract

This study was conducted to investigate the relative dominance of visual, auditory and olfactory cues in lambs' distinction of their own mother from alien ewes. Subjects were eight Suffolk lambs and were given a series of 20 choice trials between their own and alien mothers in a Y-maze. In the choice trials, four kinds of sensory cues (compound and one of visual, auditory and olfactory cues) were provided for lambs. As results of χ2-test, only five subjects exposed to the compound cues could significantly choose their own mother. The Wilcoxon rank-sum test showed that lambs exposed to the compound (P < 0.05) and the visual cues (P < 0.10) tended to choose their own mothers than alien ewes. The analysis of the first ten and the later ten trials indicated significant choices of their own mothers (χ2-test, P < 0.05) by three, one, one and one lambs exposed to the compound, visual, auditory and olfactory cues, respectively. In addition, two lambs tended to choose their own mothers when exposed to the compound, visual and auditory cues (P < 0.1). It is concluded that lambs usually distinguish their own mothers by means of the compound cue, but they can distinguish their own mother in case that only one kind of sensory cue is available. The relative dominance in the sensory modalities involved in lambs' distinction of their own mothers could be visual > auditory ≥ olfactory cues in order.