Figure 3: Social interaction of parental male ICR mice with pups in a three-chambered apparatus.

(a–d) Schematic views of the social interaction chamber. New sires were separated from pups either alone (a, experiment I) or with their mates (c, experiment II) for 3, 5 or 10 min in a central compartment in the Perspex box. Then, five pups were placed in the left compartment (filled box); the opposite compartment was empty (open box), and the sire was then placed alone in the centre compartment. The movements of the sire were recorded online using tracking software. (e,f) Two representative traces of the sires’ movements during social exploration with pups in the left compartment and in the empty cylinder on the right, after separation for 10 min. Left, experiment I (b); and right, experiment II (d). (g,h) By analysing the time spent in three chambers as a function of the isolation period, social preference of the sires was quantified when they were isolated alone (g; n=20), or isolated with their mates (h; n=20). Filled, grey and white bars represent time spent in left, centre and right chambers, respectively (mean±s.e.m.). One-way ANOVA followed by Bonferroni’s post hoc test, the letters (a-c) above the bars indicate significant difference from duration in the central room at P<0.001, P<0.01 and P<0.05, respectively, and (d) denotes significant difference from the left zone at P<0.05.