Hennesy, M. B., Foy, T. 1987. Non-edible material elicits chewing and reduces the plasma corticosterone response during novelty exposure in mice. Behavioral Neuroscience 101, 237-245.

If mice were placed in a novel environment with metal foil or cardboard available, they chewed these materials. These animals had lower plasma corticosterone levels in novel cages than mice in the same environment without access to these chewable items. The results suggest that the chewing of nonedible substances can reduce the response of the pituitary-adrenal system to novelty and may therefore serve as an arousal-regulating mechanism in this species.