Van Loo, P. L. P., Blom, H. J. M., Meijer, M. K. et al. 2005. Assessment of the use of two commercially available environmental enrichments by laboratory mice by preference testing. Laboratory Animals 39, 58-67.

All three strains of mice showed a significant preference for the paper box. The paper box was much lighter [20 g] than the plastic box [95 g]. This allowed the mice to move the paper box around, manipulate it and change the position of the entrance within the cage. The plastic box seemingly was too heavy for such maneuvering and, hence, never changed its place. The mice also gnawed the paper box, occasionally nibbled an extra hole in the side, or shreeded part of the box, using the shreds to strenghten their nest. They could not do this with the plastic box. All groups of mice slept inside the paper box but they never slept in the plastic box. If they chose to sleep in the cage that contained the plastic box, they did so in the sawdust outside the box. When tissue paper was provided, the mice dragged the material into the paper box and built a nest, but they never combined this nesting material with the plastic box.