WHY NON-INVASIVE?

Until recently, genetic studies of wild non-human primate populations (henceforth called primates in this chapter) have lagged behind those of other groups of animals studied by ecologists and evolutionary biologists. During the 1980s when, for example, avian, carnivore and hymenopteran molecular studies dominated the pages of high profile journals, primate studies were notable by their absence, and, to date, with a few exceptions, this remains the case. Two reasons underlie this imbalance.

First, primate populations do not provide the necessary replicates, sample sizes and relatively simple structures of many other groups. Social systems are often complex, generation times are long and habituated groups are extremely precious commodities. Molecular ecological methods were not always able to answer the questions that primatologists wanted to ask.

Secondly, obtaining genetic material before the advent of faecal and hair genotyping was logistically and ethically almost impossible for many populations, especially in groups where habituation over many years might have been severely affected by a large-scale, invasive sampling programme. Such problems particularly prevented many of the long-term studies that characterise primatology from taking up the challenge of adding a genetic dimension, even though there was potentially a great deal of new information to be gained. Non-invasive genetic analysis using new, high precision, molecular tools is therefore an extremely important development in primatology. However, it remains extremely difficult, time-consuming, expensive and prone to error.