The ant-eating frog is one of the smallest species of vertebrates on the University of Kansas Natural History Reservation, but individually it is one of the most numerous. The species is important in the over-all ecology; its biomass often exceeds that of larger species of vertebrates. Because of secretive and subterranean habits, however, its abundance and effects on community associates are largely obscured. The Reservation, where my field study was made, is the most northeastern section in Douglas County, Kansas, and is approximately 51/2 miles north and 21/2 miles east of the University campus at Lawrence. The locality represents one of the northernmost occurrences of the species, genus, and family