Agonistic interactions were categorized by level of intensity and only the highest intensity interaction between a dyad was recorded for that five-minute period. A pooled analysis of all juvenile play behavior was conducted using a chi-squared test. The significance level for all analyses was .05. Figure 2 . Number of aggressive acts seen per session in three different density conditions.
Total aggression decreases as population density increases.
There is a significant decrease in intense aggression as population density increases as well. The decrease in mild aggression is not significant. Number of social grooming acts observed per scan. The frequency of social grooming fluctuates accross conditions, but these changes are not significant. Figure 4 .