Grouping Patterns of Argali in Ikh Nart Nature Reserve, Mongolia

Abstract

G regariousness is a common behavioural trait observed in many large mammalian herbivores. Habitat characteristics, life history, spatio-temporal resource dynamics, population density, predation risk, competition with kin and social learning often determine gregariousness in a species. These factors may infl uence grouping patterns between species as well as between sexes within a species and several of these factors may be interrelated. In this study we examined the temporal dynamics of grouping behaviour and sexual segregation in argali ( Ovis ammon ) using eight years of observations in Ikh-Nart reserve, Mongolia. We measured monthly and yearly variations in typical group sizes and used a sexual segregation and aggregation statistic to assess sexual segregation. The typical group size observed was 14.97±2.74. The largest groups within the year occurred during lambing (May-June) and mating periods (November-December). On an average, females formed larger groups than males. The sexes were segregated all year round except for the mating period and this pattern was consistent for all years. Argali grouping behaviour in Ikh Nart resembles the patterns observed in other sexually dimorphic mountain ungulates and argali subspecies across Asia.

Keywords

• aggregation
• segregation
• typical group size
• argali
• open habitats