Rat Social Interactions

Social interactions may be syncretic or disruptive. In either case they involve social signals and the response to them. A social signal may either evoke or inhibit a stereotyped behavior pantera in a concspecific. Conflict within a group is often seemingly limited by the formation of a status system. There is no good evidence of such system among "Norway" rats; but relationships of dominance and subordination do occur, at least among the males of experimental colonies. The viable of male are the alphas, which are dominant but of which there may be several in a colony, and the betas, which have adapted themselves to a subordinate role.

One alpha is equivalent to another, and one beta to another beta, as far as observation goes. Perhaps this is a primitive type of social organization, and status systems have evolved independently from it, on many lines of descent. Crowding itself does not lead to conflict, social stability depends on an equilibrium between herding and dispersal. Where there is conflict, it is possible for a rat go short of food, even though there is plenty within within its home range.

The difference between an alpha and a beta are a result of individual experience. But most of the social behavior of rat consists of stereotyped postures, sounds and odors which are probably produced without practice. The motor patterns of the two species, Rattus morvegicus and R. rattus, are closely similar, but it possible to infer important differences in the signals (pressumably odors) which evoke coitus; males of one species do not attempt coitus with females of the other. Hence a barrier between the species exites at exactly the point at which it is to be expected.