Behaviour of domestic guinea pigs and wild cavies in two tests on emotional behaviour during early and late adolescence. (A): number of virtual squares crossed in an open field test. (B): percentage of time spent in the centre of an open field. (C): number of entrances into the light area of a dark-light test. (D): percentage of time spent in the light area of a dark-light test. Bar charts represent medians and “X”s represent single individuals. NDomestic = 10, NWild = 8; T = p ≤ 0.1; * = p ≤ 0.05; ** = p ≤ 0.01; *** = p ≤ 0.001.