Mutual recognition between ewes and lambs.

Studies to investigate the relative value of sight, hearing and smell in mutual recognition between ewes and lambs are described. The method used was to alter clues that could aid in recognition, rather than interfering with the animal's sensory perception. When lambs were coloured with powdered dyes to change appearance, this produced marked avoidance by the dams of the treated lambs. When lambs were partially coloured, the ewes' greatest reaction was shown to lambs whose heads were coloured. Other experiments compared the role of vision and hearing by observing recognition when the ewes or lambs were hidden behind screening, or muted. The results indicate that while olfaction is important for recognition when the ewe and lamb are close together, visual clues are of major importance in maternal discrimination and auditory clues are important for the lambs as they get older.