Behaviour 2019
Investigating the Acoustic Directionality of Mouse Ultrasonic Vocalizations
Yichong Ma, Megan Warren, Joshua Neunuebel. University of Delaware, Newark, DE, United States

Select members of the animal kingdom produce ultrasonic vocalizations (USVs) as a means of communication, navigation, or predation with the directionality of the signal facilitating the process. The utility and characteristics of mouse USVs, however, are less clear. Using an 8-channel microphone array, we recorded, localized, and assigned USVs to individual mice that were singly housed (n=29) or socially interacting (male-female dyads, n = 13; 4-mouse, mix-sex groups, n = 11). Males emitted a total of 3,675 (100%), 22,268 (84.48%), and 73,488 (82.05%) of the assigned vocalizations when in isolation, interacting with a female, or socializing in a group. By examining the relationship between the USV sound intensity on the eight microphones and the head directions of the mice, we observed that male mice consistently produced broadly directional USVs across all three contexts. USV intensity was the strongest in the direction the mouse was facing and weakened as the phase angle approached the opposite direction the mouse was facing. The results show that male mouse USV directionality is broadly tuned, and these sensory signals may convey information about the location of the vocalizer.