Measures of activity in captive monkey groups

Two measures of group activity were assessed using 14 captive groups of pigtail monkeys (M. nemestrina). Absolute frequencies of movement of individuals (a direct measure of activity) was used as a criterion in the evaluation of a sampling technique (an indirect measure of activity). The indirect measure involved monitoring the frequency of movement of individuals past a fixed point in the environment. The indirect measure correlated highly with the criterion measure (r=.91). use of indirect measures of activity such as the one described here can increase the efficiency of data collection by allowing observers sufficient time to monitor a greater range of behaviors. However, sampling techniques should be carefully evaluated in an appropriate context before they are adopted for general use.