The findings are presented from a 10-week field study on Saimiri oerstedi during mating season in southwestern Panama. The main study troop consisted of 23 monkeys. It used a home range of 0.175 km2 (43.5 ac) which was not a defended territory. Food was apparently scarce and the monkeys spent 95 % of each hour of their 14-hour day engaged in travel and foraging. Adult females, infants, juveniles and sub-adult males traveled as a cohesive, integrated unit. The troop’s 2 adult males usually traveled at the edge of the troop. A young adult male traveled further at the periphery of the troop. All overt social interactions were infrequent.