SOCIAL-BEHAVIOR OF PSAMMOMYS-OBESUS (RODE NTIA, GERBILLIDAE) UNDER SEMINATURAL CONDITION - A SETTLEMENT OF HIGH-DENSITY

A group of Psammomys obesus Cretzchman, 1828 (4 adult males and 4 adul t females) was studied after a breeding season (October-November, 1994 ) under seminatural conditions (open-air enclosure of 76 m(2) area) in Southern Israel. Although there were many contacts, gerbils behaved a s strictly (solitary) animals. Four of them protected small territorie s with food caches in burrows, whereas other four animals preferred to steal food from the burrows of the territorial ones. A steady asymmet ry of relationships was mostly pronounced when aggressive interactions had been considered. A simple sequence including 2-3 elements of beha vior was characteristic of the most interactions. Approaches (but not escape of contacts) attacks, sniffing and allogrooming were the most c ommon patterns. A stable system of relationships between individuals e xisted until sudden death of one of the territorial males. Only after that some individuals changed their social ranks. The reasons for diff erence in social organization between P. obesus and its ecological equ ivalent Rhombomys opimus are discussed. The comparison of these two sp ecies, one of them with solitary-territorial (P. obesus) and the other forming Family-groups (R. opimus), shows that herbivory, food catchin g and diurnal activity are not the factors responsible for sociality.