Behaviour of 40,XY (n = 25) and 39,XY*O (n = 19) mice in automated homecages over a 24 h period (lights off after 12 h). (A) 39,XY*O mice showed heightened reactivity to the novel environment (0–3 h), and increased activity during the dark phase (12–24 h) relative to 40,XY mice as indexed by lateral activity. *Corrected p-value <0.05 for post hoc comparison. (B) 39,XY*O mice made significantly more revolutions in the homecage running wheels throughout the testing period relative to 40,XY mice. (C) 39,XY*O mice spent significantly less time in the shelter throughout the testing period than 40,XY mice.