CONVERGENCES AND DIVERGENCES IN COMMUNICATION AND SOCIAL-ORGANIZATIONOF DESERT RODENTS

Has behaviour of desert rodents evolved to show convergences in the sa me way as morphological and physiological traits? To answer this quest ion, I compared social behaviour and communication of rodents from des erts in North America, Africa, Eurasia and Australia, Most desert rode nts, except those from Australia, sandbathe and footdrum as primary mo des of communication. In contrast, social behaviour in desert rodents has evolved across a wide spectrum of sociality. The most highly evolv ed social organisation in mammals occurs in two species of eusocial mo le-rats from arid deserts in Africa, Asian gerbils live in stable fami ly groups, and jerboas in northern Africa may be socially tolerant. Th e heteromyid rodents from North America, however, live alone in a soci al structure maintained by neighbour recognition. These communication convergences and social divergences may be explained by the evolutiona ry history of the rodents and by contrasts in resources, predation and climate. Mole-rats must cooperate to harvest dispersed underground tu bers in arid environments. Varied diets and cold climates possibly sel ected for group living in the highly social gerbils. The long and succ essful evolution of heteromyid rodents as solitary granivores may expl ain why they have not taken the next step in social evolution.