Social organization in the mountain nyala (Tragelaphus buxtoni) population in the Bale Mountains National Park, Ethiopia

摘要: This study was conducted in 2009 and 2011 the Bale Mountains National Park Ethiopia to assess social organization of endemic endangered mountain nyala. The main objectives this were identify group types nyala park, determine frequency occurrences, sizes number age/sex categories types. Based on composition, five distinguished: all-male, all-female, male-female, female-juvenile male-female-juvenile A total 572 groups 5187 individuals nyalas recorded during period. Overall mean typical for species 9.1 ± 0.5 (range: 1–107) 24 animals, respectively. Male-female-juvenile type most frequently observed (31% records), contained highest proportion animals (64%) had largest size (18.5 0.8) (31.9) than other Lone constituted 16.3 ~2% recorded, respectively, which over two-thirds them adult males. Both each category across significantly increased when they associated with one or two not associated. In general, data presented here represents first detailed information available species’ behaviour provides important base-line information.   Key words: Group size, nyala, group, organization.