EARLY EXPERIENCE AFFECTS DEVELOPMENTAL BEHAVIOR AND TIMING OF HAREM FORMATION IN MISAKI HORSES

A study was made of the behavior of young male Misaki feral horses in the developmental stage, by observing nine of them once a week from Ja nuary 1988 to December 1996. The relationship between behavior before separation and in the developmental stage was also investigated. This stage begins just after young males separate from their natal band or mothers, and it continues until they start to form harems. The duratio n of the developmental stage in the study ranged from 0.6 to 3.9 years , depending on the age of the young males at the time of separation. Y oung males associated with three types of social groups at the beginni ng of the developmental stage, according to their social groups before separation. These were bachelor groups, harem groups and wandering fe male groups. During this period, males joined the three groups, mixed sex groups and sometimes were solitary. It was considered that these a ssociations provided a good opportunity for males to acquire different behavioral patterns and experiences before they entered the next stag e. Depending on the groups with which they associated, young males tha t spent more time with bachelor groups had the longest average develop mental stage. They associated with harem groups more often during the breeding season and more frequently with other groups or were solitary during the non-breeding season. This may be a transition period becau se by the end of this stage all males had spent time in solitude befor e forming their own harem bands. (C) 1998 Elsevier Science B.V. All ri ghts reserved.