The results of the present study confirm that it is feasible to collect data on basal metabolic rates from large cetaceans in zoological parks using indirect calorimetry.  The system that was developed for the present study proved to be portable and effective, and was readily and rapidly accepted by the animal.  Our results are support the hypothesis that adult killer whales have a basal metabolic rate consistent with predicted values for an adult terrestrial mammal of comparable mass.  However, since these data relate to only a single ex situ adult whale, where a variety of factors may influence metabolic rate, caution must be exercised when extrapolating to in situ whales.  The present study describes a methodology that can be applied to ex situ cetaceans to expand the available database for BMR data and metabolic rate values for the largest individual odontocete measured thus far and expanding the database for approximating energy requirements for in situ killer whales.  The results of the present study are not consistent with suggestions that odontocetes have elevated basal metabolic rates, but instead lends cautious support to the notion that at least some species may have BMRs similar to terrestrial mammals of comparable size.