Aggression and social spacing in light horse (Equus caballus) mares and foals

Aggression and social spacing were studied in 14 light horse mares and thei r foals living at pasture. Focal samples were collected on each mare-foal d yad for 6 to 10.5 h from 2 months of foal age until weaning at approximatel y 4 months of age. Observations on foals continued until approximately 6 mo nths of age for 7.5 to 10.5 h per foal. Every 2 min the identities of all i ndividuals within 5 m were recorded. All occurrences of agonistic behavior, and the participants, were recorded during the focal samples. In addition, during feeding of supplemental grain, all occurrences of agonistic behavio r by all subjects were recorded. Significant correlations were found betwee n mare rank and the rank of foals both prior to and after weaning. Before w eaning, the rank of the foal was significantly correlated with birth order. No significant correlation between birth order and foal rank was found for the post-weaning hierarchy. An animal's gender had no significant effect o n foal rank or the choice of preferred associate. Both prior to and after w eaning, foals associated preferentially with the foal of their dam's most p referred associate. In addition, significant positive correlations were fou nd between rank of mares and foals and the rate at which they directed aggr ession to other herd members. (C) 2000 Elsevier Science B.V. All rights res erved.