Figure 4

Responses of two-pup (N = 11) and four-pup litter (N = 11) mothers; (a) intervals spent in zone 4 (closest to the loudspeaker) and (b) intervals with vocalizations during playback of unfamiliar pup calls on day 8 and day 20 of lactation (experiment 2). Each box plot depicts median with inter-quartile range; whiskers extend to max. 1.5 times the inter-quartile range, outliers are shown as circles.