Behavior of free-ranging macaques after intraventricular 6-hydroxydopamine.

Macaques (Macaca mulatta) observed in a free-ranging colony on Guayacan Island, Puerto Rico, were significantly different in their social interactions, initiatives, facial expressions, and postures after intraventricular 6-hydroxydopamine compared with sham-treated and field controls. This study extends the known effects of 6-hydroxydopamine and catecholamine depletion to the social interactions of a higher primate species under free-ranging conditions.