M. Haney et Ka. Miczek, ULTRASOUNDS DURING AGONISTIC INTERACTIONS BETWEEN FEMALE RATS (RATTUS-NORVEGICUS), Journal of comparative psychology, 107(4), 1993, pp. 373-379
Defensive and vocal behaviors of 18 female Long-Evans rats (Rattus nor
vegicus) in encounters with aggressive, lactating conspecifics were ex
amined in order to determine if female rats emit ultrasounds during ag
onistic interactions and to characterize any such calls. The subjects,
selected during estrus or diestrus, were exposed to 1-min attacks at
25-min intervals. Between attacks the subjects were threatened by the
aggressor but protected by a wire-mesh cage. Female rats emitted both
high- (32-60 kHz) and low-frequency (20-32 kHz) ultrasonic calls in ag
onistic encounters, with the rate of high-frequency calls enhanced dur
ing estrus. Low-frequency ultrasounds were shorter in duration and hig
her in frequency than those emitted by male rats in similar conditions
. We conclude that female rats emit ultrasonic calls during defensive
responding and that the characteristics and rate of calling vary as fu
nctions of sex and gonadal hormone state.