Animal Welfare Information Center Newsletter, Winter 1997/1998, Vol. 8, no. 3-4

Figure 2 (top). Mean number of intervals engaged in object interaction, by enrichment condition and age.

Figure 3 (bottom). Median number of intervals engaged in aggression, by age.

Cheryl Arnold and Robert D. Westbrook "Enrichment in Group-Housed Laboratory Golden Hamsters" Animal Welfare Information Center Newsletter, 8(3):1-2, 22-24, Winter 1997/1998.