EFFECTS OF ENVIRONMENTAL AND SOCIAL CONDITIONS ON THE AGONISTIC BEHAVIOR OF THE MONGOLIAN GERBIL (MERIONES UNGUICULATUS) (TERRITORIALITY, DOMINANCE, AGGRESSION)

The Mongolian gerbil is a colonial, burrowing rodent inhabiting deserts and semideserts. The burrow and burrow-related activities play a central role in the gerbil's environmental adaptation and may be a focus for social interaction and territorial behavior. If the gerbil's territoriality is influenced by the characteristics of its residence then, even in captivity, experimental environments closer to its natural habitat should foster stronger aggressive responses toward intruders than more dissimilar ones. Furthermore, potentially reproductive female-male pairs should be more affected by the presence of burrows than unisexual male pairs.^ A partition divided a 183 x 61 x 61 cm (6 x 2 x 2 ft) enclosure into two equal compartments. In three different environmental conditions, part of the floor was either left in place or removed to give access to tanks filled with dirt or hay. In two social conditions one female-male pair or two males were introduced in each of the two compartments. In the "Dirt" and "Hay" condition the animals burrowed and built underground nests and food chambers. In "Flat" they built shallow surface nests. On the seventh day of residence the partition between compartments was removed.^ The measures of severe fighting and death indicated a strong environment by social group interaction. The female-male groups showed maximal aggressiveness toward intruders in Dirt and less in Hay and Flat, whereas the male-male groups were not significantly affected by environmental change. The measures of mild fighting, threat, and chasing present a less clear picture and are discussed in terms of possible influences of the experimental arrangement. The differences in behavior between the female-male and male-male groups are discussed in terms of differential reactivity to environmental conditions and differences in the nature of the aggression displayed. It is argued that the agonism of the male-male groups may have been regulated by dominance relationships, whereas the aggressiveness of the female-male groups was of a predominantly territorial nature. The susceptibility of these two forms of social utilization of space to environmental and social conditions is discussed. ^