Newman, A. 2010. A simple improvement of rodent tunnels for environmental enrichment. Animal Technology and Welfare 9, 57-58.

We found commercially available rodent tunnels are too small in diameter when the rat reaches a size <250 g. We obtained tunnels from a local plastic retail company; these tunnels have an internal diameter of 9.5 cm with a length of 20 cm. We found placing more than 2 tunnels to a cage restricted floor area and, although rats are very gregarious and share tunnels, they sometimes like to be on their own. The tunnel structures described in this article were devised to take account of this preference and at the same time gave rats a more interesting environment. We describe using a glue gun to glue 2, 3, or 4 tunnels together, forming various structures. Two tunnels can be glued together, one next to the other; a third or fourth tunnel can be glue on top of the first two. We found the 4 chamber design allowed more activity and the rats liked sitting on top of these to observe their surroundings.