CUMMINCS and THOMPSON: GRAY WHALES 



havior had a visual function, i.e., they were 

 probably looking for killer whales. This impli- 

 cation does not necessarily exclude swallowing, 

 but we doubt that the gray whales were feeding 

 under these circumstances. 



Moreover, concerning Walker's assertion that 

 gray whales "navigate mostly by echolocation," 

 although it has been clearly demonstrated that 

 porpoises can echolocate underwater objects (re- 

 viewed by Norris, 1969) , it is not known whether 

 they normally navigate at sea by this means. 

 "Echolocation-like" (Asa-Dorian and Perkins, 

 1967) and "echolocation" sounds (Poulter, 1968) 

 were recorded in the presence of gray whales, 

 but there was little evidence that the sounds 

 actually were from the whales. There are in- 

 numerable sounds in the ocean and many pos- 

 sible sources, but the matching correlations are 

 often difficult to achieve. In any event, we pre- 

 fer not to use the term "echolocation" in de- 

 scribing the underwater sounds of animals un- 

 less they are known to have such a function. 

 Although we have recorded a few clicklike sounds 

 during five seasons of work with gi'ay whales, 

 we have never been able to associate them with 

 the whales. The clicklike sounds that were re- 

 corded, while using an array of hydrophones and 

 a technique of computing sound source locations, 

 originated from an area where, apparently, there 

 were no gray whales. 



Bioacousticians are not in a position to say 

 with any certainty that gray whales do not 

 echolocate; future experimental work could pos- 

 sibly show that they do. However, our own 

 research with 7 of the 10 species of mysticate 

 whales has yet to reveal any data to suggest that 

 a member of this order uses underwater echolo- 

 cation. 



Whales normally exhale at the surface of the 

 water with the blowholes exposed, but Hubbs 

 (1965) has reported underwater blows by four 

 species of whales — humpback, Megaptera no- 

 vaemigliae; fm., Balaenopter a phy solus; striped 

 dolphin, Lagenorhynchus obliquidens; and the 

 gray whale. In addition, he noted gray whales 

 to refrain from spouting, skip an inhalation, or 

 barely protrude their blowholes in the presence 

 of killer whales. In the same report, Hubbs 

 associated these behaviors with "strange or 



frightening stimuli." We were not close enough 

 to see if fleeing gray whales exhaled underwater, 

 but our other cited observations of gray whales 

 covertly avoiding the killer whale sounds cer- 

 tainly parallel Hubbs' observations. 



Unfortunately, there was no record of the 

 killer whales' behavior during the original re- 

 cordings of the phonations used for playback. 

 We advise others who may be involved with 

 sound playback to use appropriately meaningful 

 signals, whenever possible. For example, under- 

 water sounds that are part of an animal's re- 

 productive behavior may have little or no effect 

 on nonbreeding animals. Likewise, feeding 

 sounds may not affect animals that are in a 

 state of alarm. If possible, we would have com- 

 pared the results of playing back two sets of 

 killer whale sounds in the present experiments 

 — one recorded from attacking whales in a pred- 

 ator-prey situation, if indeed killer whales utter 

 sounds at this time, and another from killer 

 whales that apparently were not feeding or 

 preying. 



Based on the methods of this study, our co- 

 workers. Dr. James F. Fish, and John S. Vania 

 subsequently used killer whale sound playback 

 to keep white whales, Delphinapterus leucas, 

 from entering the Kvichak River, Alaska, where 

 they eat young salmon before the fish can get 

 to the open sea (Fish and Vania, 1971). 



ACKNOWLEDGMENTS 



We thank Dr. James F. Fish for helping with 

 the field work and reviewing the report; Bruce 

 C. Parks and Robert Z. Hester for operating 

 the research vessel; Richard N. Bray, George 

 E. Lingle, and John B. Webster for assisting 

 with the data analysis; and Shelley L. Steahl 

 for helping to prepare the manuscript. 



LITERATURE CITED 



Asa-Dorian, P. V., and P. J. Perkins. 



1967. The controversial production of sound by the 

 California gray whale, Eschrichtius gibbosiis. 

 Nor. Hvalfangst-Tid. (Norw. Whaling Gaz.) 

 56(4) : 74-77. 



529 



