Use of Corn-Husk Nesting Material to Reduce Aggression in Caged Mice

We examined the use of corn-husk nesting material as a means of reducing aggressive behavior in group-housed mice. The experiment was performed by using 128 BALB/cAnNHsd mice. Mice were randomly assigned (8 mice/cage) to one of two groups: one housed in cages enriched with nesting material in addition to standard bedding, the other housed in cages with standard bedding only. Each mouse was examined on days 4 and 7 for evidence of visible wounds. On day 4, the addition of nesting material significantly decreased aggressive behavior for the enriched group, as indicated by mean number of wounds per group. By day 7, the amount of aggression was the same between the two groups. We concluded that use of nesting material decreased aggressive behavior in the mice during the initial introduction phase by providing flexible avenues of escape for subordinate mice. In addition, mice derived enrichment benefits by being provided a diverse cage environment that promoted natural nesting behavior.