ADAPTIVE PACIFISTIC BEHAVIOR IN SUBTERRANEAN MOLE RATS IN THE SAHARA DESERT, CONTRASTING TO AND ORIGINATING FROM POLYMORPHIC AGGRESSION IN ISRAELI SPECIES

Aggression is a polymorphic trait that occurs in subterranean blind mo le rats of the Spalax ehrenbergi superspecies in Israel (NEVO et al., 1975, 1986; NEVO, 1991). We found Egyptian mole rats in the isolates t o be pacifistic. This supports our evolutionary theory of aggression i n Spalax which predicts that aggression should decrease in the desert habitat (NEVO et al., 1986), presumably to minimize overheating, water and energy expenditure. The described behaviour is a pre-requisite fo r social evolution. We hypothesize that pacifistic behaviour in Spalax isolates in North Africa has been adaptively selected for survival in the harsh Sahara desert ecology.