Investigations of the nature of lambs' individual odour signatures

Abstract

In an attempt to gain further insight into the sources and characteristics of lambs' olfactory signatures, we observed ewes' responses to familiar and alien young whose odours were experimentally manipulated. When tested several hours after parturition, ewes accepted their own lambs that had been anointed with an artificial odorant at birth, but rejected alien lambs bearing either that same familiar scent or a novel odour. Ewes nonetheless appeared capable of discriminating between alien lambs treated with the familiar versus novel odorants. Alien young anointed with amniotic fluid collected from the ewes' own offspring were rejected to the same extent as aliens treated with their own (alien) amniotic fluid. Thus, neither artificial odorants nor amniotic fluid masked the lambs' individual odours, nor did they preclude ewes' learning of those phenotypic traits. Ewes may be predisposed to learn a limited range of biological odours associated with their newborn lamb, and such individually recognizable cues appear not to be carried in the amniotic fluid nor acquired postnatally from the mother.