Responses of adult mice to models of infant calls.

Abstract

Lactating female, primed female, naive female, primed male and naive male T.O. Swiss mice were tested individually for approach responses to an electronically generated model of a newborn mouse pulse in a small choice chamber. Lactating females and primed females made more responses than did other mice, and priming increased the responsiveness of males and females. Primed females were then tested with 5 different electronically generated ultrasonic signals. More approaches were shown to a 65-45 kHz signal than to one of higher or lower frequency but of the same bandwidth. An 80 ms pulse elicited more approach responses than a 15 ms one. The responses of primed female house mice were tested as a comparison with T.O. Swiss mice. They showed a slightly lower response level but, like T.O. Swiss mice, made more approaches to a pulse of 65-45 kHz than to one of 75-55 kHz. The use of electronically generated signals may help to reveal the important features of infant rodent calls that elicit adult approach behavior. The method allows greater flexibility than does the use of replayed tape recordings.