Effect of the post-weaning environment on the climbing behaviour of wild and domestic Norway rats.

The climbing behaviour of wild and domestic Norway rats (Rattus norvegicus) was compared after early rearing in three post-weaning environments offering different climbing experiences. Wild rats climbed in the test apparatus even when denied early climbing experience; male domestic rats did not. Early climbing experience increased the climbing scores of both stocks but influenced the climbing proficiency of wild rats only. Treatment differences in climbing behaviour may be related to specific motor experiences gained during development and the effect of early experience on the response to a novel environment (test apparatus). Stock differences in climbing behaviour may reflect a general reduction in motor activity among domestic rats and their reduced sensitivity to stimulus change or novelty.