Ultrasound by mouse pups from deaf and hearing strains.

Pups aged 1 to 10 days, of deaf and hearing mouse strains, were monitored with an ultrasound detector while submitted to standard conditions of cold, isolation, and retrieving. The number of detections varied with the age of the pups and with the type of treatment (as established previously) but not with the genotype of the pups. Thus, occurrence and changes with age in ultrasound emission do not seem to be greatly influenced by their effects upon adult behavior.