TEMPORAL ACTIVITY OF THE MARA (DOLICHOTIS -PATAGONUM) IN THE MONTE DESERT, ARGENTINA

The mara is a caviid rodent, endemic and resident in the arid region o f central and south Argentina. Little is known about its ecology in th e wild, but its diurnal and superterrestrial way of life rises interes t concerning its temporal activity rhythms related to environmental va riables, as well as behavioural strategies for the species' adaptation to semi-desert environments. Surveys over two or three consecutive da ys were made from March 1982 to March 1983 and from October 1986 to Ju ly 1988, recording the number of active animals and environmental vari ables. It was demonstrated that the annual activity of D. paragonum wa s positively influenced by light, precipitation and temperature and ne gatively by darkness and relative humidity. These variables probably i nfluence the long-term endogenous rhythms of the species. The daily ac tivity was unimodal in winter and bimodal in the other seasons, and it was related especially with temperature. A favourable thermal environ ment was detected near 20 degrees C. Daily activity of mara reduced du ring winter and summer with alternate periods of activity and rest, pr obably related to the species energetic balance. These strategies are important for the successful adaptation of the mara to Monte environme nt.