POPULATION-DYNAMICS OF THE FOSSORIAL RODENT CTENOMYS TALARUM (RODENTIA, OCTODONTIDAE)

As part of a study on the ecological strategies related to adaptation to the subterranean habitat of genus Ctenomys (tuco-tucos), a natural population of C. talarum was live-trapped at Necochea (Buenos Aires Pr ovince, Argentina) with the aim of providing information on its popula tion ecology. Population size was consistently low throughout the stud y and was related to the low habitat productivity. Mortality rates wer e low, although for juveniles the estimations were higher than for adu lts. Individuals have an average life expectancy of 22-25 months, but some individuals lived at least three years. Reproductive activity sta rted by July and ended by March, when last known pregnancies were reco rded. This long reproductive season allowed a gradual incorporation of young over an extended period of time, with a restricted period of re cruitment lacking. Sex ratio did not depart from 1:1 and appears to be density dependent. The spatial distribution of individuals was clumpe d and corresponded to the patchy distribution of suitable habitats. Th e results are compared and contrasted with those from previous demogra phic studies performed in other conspecifics as well as in other subte rranean rodents.