Scientists believe that primates – like humans – use mainly visual cues and sometimes sounds for sexual signalling. It is likely, though, that this type of communication also involves smell – a component of sexual signalling that is not well understood. The EU-funded PRIMOLF (Microsmatic primates revisited: Determining the importance of olfaction in primate communication) initiative gathered detailed information about sexual signalling, including the use of smell, from baboons. For 4 months, researchers spent time with 15 captive, adult baboons – 12 of which were female. Over hundreds of hours, scientists observed the animals and recorded their behaviour and bodily changes (menstruation and genital swelling). Each day the scientists sampled the baboons' saliva and vaginal secretions, and took vaginal swabs and photos of their genitals. PRIMOLF measured the sex hormones in the animals' saliva, studied the cellular structure of the vaginal cells and chemically analysed vaginal odours. After 329 hours of observation, the team collected 1 872 digital images and hundreds of samples covering 36 menstrual cycles. They identified 66 volatile compounds. The resulting data set will improve understanding of the function of sexual signals. In particular, researchers will be able to examine how the different types of signals used by females work together and influence male behaviour. This study is the first to look at odour as an integrated part of sexual signalling in primates. The work could contribute to developing a better-defined model of sexual communication in primates, with potential insights into human behaviour.
Baboons, primates, odour, sexual signalling, PRIMOLF