Foraging activity of subterranean termites was studied on grids of artificial food units (toilet paper rolls) and on natural foods on the surface using belt transects. Preferred forage items were portions of Yucca elata logs and cattle dung which provided large surface area contact with the soil. Foraging at the surface occurred at soil temperatures > 3-5 degrees Celsius at 15 cm depth and at soil moisture tensions between 0 and minus 140 bars. Estimated foraging group densities were 440/ha and 61/ha for 2 areas. Differences in foraging group densities were related to soil texture and depth above the caliche. Mid-summer field determined consumption rates were 7.9+-2.8 and 1.2+-0.04 kg/ha on the 2 study areas. We concluded that termites account for the consumption of ca. 50% of the production in creosotebush and mesquite-yucca grassland communities in the Chihuahuan desert.