Absence of escalation of aggressive behaviors during the paired male encounters.

<p>Occurrences pair⁻¹ (means ± s.e.m.) of high-intensity aggressive behaviors (<i>hold</i> and <i>lunge</i>, combined) through successive 10-min intervals within the encounters. Only the results for the day 3, 4, and 6 age cohorts are depicted because of the relative infrequency of these behaviors in the day 1 and 2 age cohorts.