Ultrasonic calls produced by three laboratory strains of Mus musculus

Abstract

Young of three strains of laboratory mouse, C57/BL6/J, SEC1Re/J and BALB/c were examined for the first 14 days of life. Ultrasound output by the young was measured daily for each of two pups from each litter over a period of 5 min. The young were not subjected to a marked change in external temperature during any stage of the observations. Differences between the strains were marked, with BALB/c and SEC producing more ultrasound daily than C57 over the first nine days of life, and maintaining a high level of ultrasound output for 2–3 days longer than C57.