ULTRASONIC VOCALIZATIONS OF DEFEATED MALE RATS

Used the resident-intruder aggression paradigm in 6 experiments to investigate the conditionability of 20-25 kHz vocalizations of defeated male Long-Evans hooded rats (territorial intruders). 90% of intruding males consistently emitted ultrasounds in the presence of an inaccessible aggressive male with which they had received repeated defeat experiences (4-22 attacks). Intruders tested 1 wk after initial conditioning emitted 20-25 kHz calls of comparable latency and number in the presence of familiar and unfamiliar aggressors. Defeated Ss emitted few or no ultrasonic calls in response to male or female castrates, immobilized aggressive males, anosmic males, or the soiled bedding material of an aggressor's home cage. Vocalizations by aggressors (45-70 kHz) were not required to stimulate production of 20-25 kHz signals of defeated Ss. Though olfactory cues alone were not sufficient to elicit ultrasonic vocalizations, they appeared to be an important part of the stimulus complex capable of consistent elicitation. (42 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1979 American Psychological Association.