The influence of group size and neighbors on vigilance in two species of arboreal monkeys

摘要: (Acc. 5-VIII-1997) Summary In theory, one of the main benefits group-living is sharing vigilance among groupmates. However, data on scanning in redtail and red colobus monkeys indicate that only class individuals each species derives clear from shared vigilance. Moreover, expected negative relationship between individual social group size was not met these monkeys. Nor time spent influenced by sex or composition groups. Shared observed adult males females when they had neighbors within 2 m. Red saved 10% their neighbor m, while 16% under same conditions. No other age-sex demonstrated a significant decrease. The role near has been underemphasized previous work grouping vigilance, an oversight made more serious because often confounded spatial cohesion size. redtails, but colobus, number m significantly positively correlated with This prompts hypothesis inconsistency poor explanatory power studies