HYDRODYNAMIC ANALYSIS OF CETACEAN PERFORMANCE.

(1) Results of performance tests with the dolphin Notty show no unusual physiological or hydrodynamic performance. The test conditions suggest, however, that hydrodynamic performance was adversely affected by one or more environmental factors. (2) Analysis of cetacean sightings and performance tests reported in the available references indicates that the drag of these animals is significantly lower than expected. Several low-drag hypotheses offer possible explanations. Additional, and more accurate, top-speed measurements are needed, preferably taken under natural oceanic conditions. (3) A brief analysis and summary of the available literature show that several types of free-riding behavior are exhibited by cetaceans. Different explanations for the bow-riding ability of dolphins exist, and the true explanation may be a combination of various explanations. (Author)