Social complexity and differentiation of social roles
Like feral horses, the nucleus of the harem of Przewalski horses in the semi-reserves appears to be the adult mares with their offspring of the past 2-3 years. Social attachment between individual mares and between juveniles are evident at various levels. One Przewalski mare even played a role as godmother to a foal of another mare, defending it when approached too closely by others.
Although ultimately the most dominant member of a harem, mostly the stallion, can influence the group's activities, initiative and leadership are not shown only by that individual (WARING 1983). It is not always the dominant Przewalski mare of stallion which initiates travelling for instance, but also lower ranking adult mares. The stallion is more often at the rear. The stallion's role is much more differentiated in the semi-reserves and not restricted to siring mares. The stallion takes the leadership role if intruders enter his territory. He always takes up a position between his band and the intruder(s).
Herding was seen towards a mare, which could not leave her weak wounded foal. He pressed her to follow the group which had moved away out of sight. The harem stallions are very watchful and are often seen patrolling along the fence in case of disturbances. Although more behaviour data are needed, we already have the impression that the Przewalski horses born in the semi-reserves have become very vigilant. Attachment and social facilitation do influence that. Vigilance is one of the basic characteristics associated with zebra predator avoidance together with grouping, male defence of harems and flight (BERGER 1986).
Predator pressure of wolves will be strong for the Przewalski horses when they will be released into reserves in Middle Asia and Mongolia. It is therefore important that Przewalski horses which will be released into these reserves have been reared in social groups in semi-natural environments. Suitable animals for release have to be selected on their life history and behavioural competence of Przewalski horses for re-introduction.
It is especially important for stallions, on whom group cohesion might depend considerably after release into the wild. The stallions in our bachelor groups have split into two groups. They bide their time with play -fights and learning to assess the physical capabilities of each other, practising skills they need later. It is not only strength, age and aggressiveness which play a role, but also the experience of dominance in a bachelor group. They are very watchful in case of disturbances; group together in their own band, sometimes both bands group together.
All these factors are very important for the selections of suitable animals for re-introduction besides the genetic criteria. The experience of the first released Przewalski horses will be improve the selection and preparation of horses to be transported to the reserve site.