Wild ungulates can recognize certain predators without previous experience, but this innate ability may be relaxed under domestication. Using naive dairy calves, Bos taurus, we examined the effects of exposure to a predator odour (coyote, Canis latrans, urine) and two control odours (deer urine and water) on (1) latency to approach a milk food reward, (2) exploration, vigilance and locomotor play, (3) magnitude of the startle response to a sudden noise delivered upon arrival at the feeder and (4) heart rate during feeding in 10 min trials on three consecutive days. In response to predator odour, calves delayed feeding and tended to explore more and play less in the first 30 s of the trial compared to calves exposed to control odours. The duration spent feeding and standing with the head raised (i.e. vigilant) did not differ among treatments. On the first day, calves exposed to predator odour startled more to a sudden noise than control animals. Mean heart rate during feeding decreased across days in the control treatments, but not in the predator treatment, suggesting a sustained response to the predator odour. We conclude that naive domestic calves retain the ability to distinguish between predator and nonpredator odour.

中文翻译：

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幼稚的家养 Bos taurus 小牛识别出犬科动物捕食者的气味

野生有蹄类动物可以在没有经验的情况下识别某些捕食者，但这种先天能力在驯化下可能会有所放松。我们使用幼稚的奶牛犊，Bos taurus，研究了暴露于捕食者气味（土狼、Canis latrans、尿液）和两种对照气味（鹿尿和水）对（1）接近牛奶食物奖励的潜伏期的影响，（2 ) 探索、警惕性和运动能力，(3) 到达喂食器时对突然发出的噪音的惊吓反应的程度，以及 (4) 在连续三天的 10 分钟试验中喂食期间的心率。为了应对捕食者的气味，与暴露于控制气味的小牛相比，小牛在试验的前 30 秒内推迟进食，倾向于探索更多，玩耍更少。喂食和抬起头站立（即保持警惕）的持续时间在处理之间没有差异。在第一天，暴露于捕食者气味的小牛比对照动物更容易受到突然的噪音的惊吓。在对照治疗中，喂食期间的平均心率在几天内下降，但在捕食者治疗中没有，这表明对捕食者气味的持续反应。我们得出结论，幼稚的家养小牛保留了区分捕食者和非捕食者气味的能力。