This study was designed to evaluate differences in desiccation rates in six species of Chihuahuan desert ants as related to size, foraging behavior, and geographical distribution. During the first 8 h of exposure, all species of seed harvesters had similar desiccation rates, and Formica perpilosa, a plant-exudate feeder, had a higher desiccation rate and lower desiccation resistance than the harvesters. Desiccation rate and desiccation resistance were not correlated with foraging behavior in Pogonomyrmex sp. and Novomessor cockerelli but were similar to those of ants from the Sahara Desert. There was no relationship between body size and desiccation rate and resistance, but female sexuals of N. cockerelli had lower rates and greater resistance than workers and male sexuals of the same species.