Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats

Applying 50 kHz USVs as a measure of positive affect, these results confirm that tickling induces positive affect in juvenile laboratory rats. We report the novel finding of sex differences in response to tickling. Females preferred tickling where the amount of pinning is minimised relative to males that showed no preference across tickling treatments. Levels of USVs suggest that females possibly found the applied treatments, including control conditions, more rewarding than males did.