We first call attention to the ecological relevance and characteristics of subterranean herbivorous rodent activities in different ecosystems. Second, we note that in arid coastal Chile the ecological impact of their activities is considerable, showing similarities, as well as important differences, to impacts in other areas of tho world. The amount of excavated soil. deposited on the surface is similar ro thar reported for pocket gophers in North America. These rodents also promote dominance of introduced mediterranean annual plants. In Chile, as in South Africa, however, they seem to greatly promote the growth of geophytes, which are their preferred food. Their activities promote large-scale soil homogeneity. We hypothesize that these aspects of their ecology in Chile reflect a close relationship between a fluctuating and unpredictable climate, a relatively constant availability of clumped geophytes, and the colonial social system of these rodents, all of which promote a slow but constant shifting of their foraging areas. Subterranean rodents certainly play an important role in determining the structure and dynamics of plants in the coastal arid ecosystem in Chile. However, very little is known about the mechanisms involved.