540 



Thompson, P. O. 1965. Deep water recordings of pinniped sounds. Proceedings 

 of Second Annual Co«^erence on Biological Sonar and Diving Mammals, 

 Stanford Research Institute. 

 Describes, in detail, underwater recordings of barking sounds from Cali- 

 fornia sea lions off San Clemente Island. Diurnal characteristics, spectrum 

 plots, and sonagrams are includetl. 



Thompson, P. O. and R. C. Cook 1967. Sound production of migrating gray 

 whales, Eschrichtius gibhosns Exrleben (abstract). Journ. Acoustical See. 

 Am., 42 (5) :1211. 

 Abstract of a paper presented to the ASA \Vhlch reports low frequency moan- 

 ing sounds from gray whales while they were migrating to Mexico from the 

 Bering Sea. 



Thompson, P. O. and R. D. Cooke 1968. Underwater sounds of migrating gray 

 whales, Eschrichtius glaucus (Cope). Jour. Acoustical Soc. Am., 4-'/ (5) : 

 1278-1281. 

 Includes methods, results, and di.scussion of work done on sound production 

 of gray whales. Three categories of sounds range in frequency from 15 to 305 

 Hz at source levels up to 52 dB re 1 microbar at 1 yd. New findings concerning 

 gray whale behavior are presented. 



Northrop, J., W. C. Cummings, and P.O. Thompson 1968. 20-Hz Signals observed 

 in the Central Pacific. Jour. Acoustical Soc. Am., JfS (2) : 383-384. 

 Reports show, 20^Hz signals from the mid Pacific area. The.se signals had 

 source levels that ranged from 65 to 100 dB re 1 microbar at 1 yd. The original 

 strength, source movement and seasonal peak suggested the sounds were from a 

 biological source, probably the finback whale. 



Thompson, P. O. and W. C. Cummigs 1969. Sound production of the finback whale. 



Balaeoptera physalus, and Eden's whale, B. edeni, in the Gulf of California 



(abstract). Proceedings of the 6th Annual Conference of Biological Sonar 



and Diving Mammals, Stanford Research Institute, p. 109. 



Describes powerful, low-frequency sounds from two species of whales found 



in the Gulf of California. Finback .signals ranged from 20-100 Hz, wliile those 



from Eden's whale averaged 124 Hz. Although finbacks have been suspected 



as sources of 20-Hz signals, these were not encountered among the 1800 phona- 



tions recorded from some 70 finbacks. 



Cummings, W. C. 1969 Whales, porpoises, dolphins and confusion. Oceans 

 Magazine, 1(4) : 30-31. 

 Discusses the problems encountered in using common names for various 

 cetacean taxa. To avoid confusion, this article suggests that the term "dolphin" 

 be avoided in favor of "porpoise", a common practice by many cetologists. 

 Johnson, C. S. 1967 The possible use of phase information in target discrimina- 

 tion, and the role of pulse rate in porpoise echoranging. In : Animal Sonar 

 Systems-Biology and Bionics, Vol. 1, 384-308 (Ed. R. G. Busnel, Laboratoire 

 de Physiologic Acoustique, Jouye-en-Josas 78, France) 

 A discussion of the paper by Evans and Powell (see reference on page 4). On 

 the basis of theoretical considerations there are phase differences in reflected 

 pulse shapes which may be utilized by the iwrpoise. An analysis of pulse rate 

 vs range and time indicates that decreasing pulse is based on time before target 

 contact rather than range. 



Johnson, C. S. 1968 Relation between absolute threshold and duration-of-tone 

 Bio- Acoustics Vol. 2, 247-260 (Ed. W. N. Tavolga) Pergamon Press. 

 Using a behavioral response method, an audiogram was determined for a 

 bottlenose porpoise. Hearing range was 70-150 kHz. 



John.son. C. S. 1968 Relation between absolute threshold and duration-of-tone 

 pulses in the bottlenosed porpoise. Jour. Acoustical Soc. Am. 4^(4) : 757- 

 763. 

 This study indicated that the porpoise, in detecting pure tone stimuli, inter- 

 grated the acoustic energy in essentially the same way as humans. 

 Johnson, C. S. 1969 Masked tonal thresholds in the bottlenosed porpoise. Jour. 

 Acoustical Soc. Am. -^-^ (4) : 965-967. 

 An analysis of hearing thresholds when a narrow band of frequencies is 

 ma.sked by broad-bank noise. 



Johnson, C. S. 1970 Auditory masking of one pure tone by another in the bottle- 

 nosed porpoi.se. Jour. Acou.stical Soc. Am. ^8(5) : 7328. 

 Lang, T. G. and H. A. P. Smith 1965 Communication between dolphins in 

 separate tanks by way of an acoustic lind. Science ^50(3705) : 1839-1843. 

 Alternating exchange of whistles occurred between two dolphins. 



