Ocymyrmex barbiger is a diurnal scavenger of arthropods in which the number of successful foraging excursions per colony per day increases with daily vapour pressure deficit. It appears that the ants make use of prey items which succumb to thermal and desiccation stress. Running speed is a function of surface temperature but progressively less time is spent searching for prey beyond a critical surface temperature with the result that the optimal search temperature for individual foragers is about 52°C. Maximal foraging activity of colonies occurs at surface temperatures corresponding to this optimal search temperature.