Figure 2.

Box plot showing that: (a) the overallsocial play frequency tends to be higher in piglets than wild boar hybrids for the whole period (Mann–Whitney exact test; p = 0.057); (b) social play hourly frequencies (age periods: T₁ = 6–20 days, T₂ = 21–35 days, T₃ = 36–50 days) are higher in piglets in T₂ (Mann–Whitney exact test; p = 0.006) and in T₃ (Mann–Whitney exact test; p = 0.001). There was a significant decrease in the social play levels across periods for both hybrids and piglets (Friedman’s tests, p < 0.05) and particularly between T₁ and T₂/T₃ (Dunn’s tests: p < 0.05). Horizontal line: median value; box: interquartile range; vertical line: minimum and maximum values in the data. NS = non-significant, ** = p < 0.01.