Consistency of temperament in bighorn ewes and correlates with behaviour and life history

Individual differences in temperament may affect how animals react to novel situations, avoid predation, invest in reproduction and behave in a variet y of social contexts. Little information is available, however, about indiv idual differences in temperament for wild animals. For bighorn sheep, Ovis canadensis, ewes captured as part of a long-term study, we compared behavio ur during handling to behaviour in the field and reproductive history. We c onsidered 'bold' ewes those that were frequently trapped during the summer, and assigned to each ewe a docility index based on her behaviour during ha ndling. Measurements of temperament for the same individual at different ca ptures were highly consistent. Temperament was not affected by reproductive status or age, nor was it related to body mass. Correlations between behav iour at the trap and in the field were weak and mostly nonsignificant, sugg esting that temperament is domain specific rather than domain general. Bold ewes tended to start reproducing earlier and have higher weaning success t han shy ewes. Variability in temperamental traits in the study population c ould be maintained by life-history trade-offs and by yearly changes in sele ctive pressures. (C) 2000 The Association for the Study of Animal Behaviour .