We have developed an effective methodology for sampling and analysis of odor signals, by using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry, to understand how they may be used in animal communication. This technique allows the semi-quantitative analysis of the volatile components of odor secretions by enabling the separation and tentative identification of the components in the sample, followed by the analysis of peak area ratios to look for trends that could signify compounds that may be involved in signaling. The key strengths of this current approach are the range of sample types that can be analyzed; the lack of need for any complex sample preparation or extractions; the ability to separate and analyze the components of a mixture; the identification of the components detected; and the capability to provide semi-quantitative and potentially quantitative information on the components detected. The main limitation to the methodology relates to the samples themselves. Since the components of specific interest are volatile, and these could easily be lost, or their concentrations altered, it is important that the samples are stored and transported appropriately after their collection. This also means that sample storage and transport conditions are relatively costly. This method can be applied to a variety of samples (including urine, feces, hair and scent-gland odor secretions). These odors consist of complex mixtures, occurring in a range of matrices, and thus necessitate the use of techniques to separate the individual components and extract the compounds of biological interest.

Female primates signal impending ovulation with a suite of sexual signals. Studies of these signals have focussed on visual, and to a lesser extent, acoustic signals, neglecting olfactory signals. We aimed to investigate the information content of female olfactory signals in captive olive baboons ( Papio anubis ) and relate these to the female fertile period. We studied eight adult females living in four groups at the CNRS Station de Primatologie, Rousset-sur-Arc, France. We used vaginal cytology to detect ovulation. We investigated the volatile component of odour signals using solid-phase microextraction and gas chromatography-mass spectrometry. We found a total of 74 volatile compounds, of which we tentatively identified 25, including several ketones, alcohols, aldehydes, terpenes, volatile fatty acids and hydrocarbons that have been identified in odour profiles of other primates. Our results show that vaginal odour intensity differs with sexual cycle stage suggesting that odour might play a role in signalling female baboon fertility. We found differences in vaginal odour between females living in all-female and in mixed sex groups but we could not distinguish the effects of group composition, female age and identity. This study of olfactory signalling improves our understanding of how female primates advertise their sexual receptivity.

Primates are traditionally considered to have a poor sense of smell. However, olfaction is important for non-human primates as demonstrated by conspicuous scent-marking behaviours in lemurs. We studied two pairs (n = 4) of crowned lemurs (Eulemur coronatus) housed at Colchester and Twycross zoos (UK) by combining behavioural observations and chemical analyses of scent-marks and glandular swabs. We recorded observations of olfactory behaviours for 201 h using instantaneous scan sampling. We investigated the volatile compounds of ano-genital odour secretions (n = 16) using solid-phase microextraction and gas chromatography-mass spectrometry. Males scent-marked most frequently, displaying ano-genital marking for allomarking, head marking for countermarking and wrist marking in specific areas of the enclosure. Females displayed ano-genital marking, predominantly on feeding devices. We detected a total of 38 volatile components in all male ano-genital scent-marks and 26 in all female samples of ano-genital odour secretions, including a series of esters, aldehydes, ketones, alcohols, terpenes, volatile fatty acids and hydrocarbons that have been identified in odour profiles of other primates. In conclusion, we found sexual dimorphism in crowned lemur scent-marking. Male head and wrist marking behaviours might play defensive territorial functions, while ano-genital marking would be related to socio-sexual communication as chemical mate-guarding. Female ano-genital marking might be involved in resource defense.

Primate chemical communication remains underappreciated, as primates are considered to rely on other sensory modalities. However, various lines of evidence suggest that olfaction plays an important role in primate societies, including the conspicuous scent-marking behavior of many strepsirrhines and callitrichines. Although lemurs typically show scent-marking, little is known about this behavior in red-ruffed lemurs (Varecia variegata rubra). We combined behavioral observations and semiochemistry analyses to improve our understanding of scent-marking in two captive troops housed at Dudley and Twycross zoos (UK). We collected olfactory behavioral observations by focusing on two family troops (N = 7) for 132 hr. We investigated the volatile compounds of ano-genital scent-marks using solid-phase microextraction and gas chromatography-mass spectrometry and compared volatile chemical profiles with features of the signaller. Males scent-marked most frequently and predominantly in specific meaningful areas of the enclosure, while within females the occurrence of scent-marking was related to their age. We found behavioral sexual dimorphism, with male predominantly depositing secretions via neck and mandible glands and females via ano-genital glands. We identified a total of 32 volatile components of ano-genital gland secretion, including compounds that have already been found in other mammals as sex pheromones and cues to fitness, in ano-genital scent-marks spontaneously left on filter paper by adult females. Our findings suggest that red-ruffed lemurs might use scent-marking to convey information about sex and female age, with male neck-marking behavior playing defensive territorial functions and ano-genital marking related to socio-sexual communication.