The use of a novel scent enrichment to improve captive primate welfare and its potential application to conservation breeding
Scent-marking behaviours are common across vertebrates, having roles in territoriality, sex identification and advertising fertility. Lemurs which rely on olfactory communication are a conservation priority and modern zoos have a role in contributing to their conservation with captive breeding programmes. But mismatches between zoo and wild environments may lead to welfare problems, which can impact upon breeding success. To improve welfare, zoos routinely use environmental enrichments, including scents (typically essential oils) which may have applications to improve breeding success for lemurs. My project aims to study the scent-marking and odour profiles of zoo-housed crowned lemurs (Eulemur coronatus) and red-ruffed lemurs (Varecia rubra). I also aim to develop a novel, biologically-relevant scent enrichment based on odour profiles. Firstly, I examined the scent-marking behaviours and odour secretions released by lemurs, by combining commonly used behavioural sampling methods (scan sampling) and cutting-edge semiochemistry techniques, including solid-phase microextraction (SPME) and Gas-Chromatography-Mass-Spectrometry (GC-MS). I found that both male crowned (n= 1) and red-ruffed (n= 1) lemurs’ scent-mark significantly more than their respective females (n = 1 for both). I identified 12 volatile compounds on female red-ruffed lemur odour samples that may provide breeding season cues and used them to develop a novel scent enrichment. Following this, I tested this enrichment with groups (n= 4) of red-ruffed and black-and-white ruffed (V. variegata) lemurs housed at Twycross Zoo (n= 2), Dudley Zoo & Castle (n= 7) and Shaldon Wildlife Trust (n= 6). To assess both welfare and breeding indicators I combined behavioural observations with faecal endocrinology using enzyme immunoassay techniques to analyse cortisol and testosterone. The enrichment had effects on welfare, with a significant increase of active behaviours observed during the enrichment period in comparison to the baseline; however, stress-related behaviours and faecal cortisol concentration also increased. Encouragingly, the scent enrichment triggered sexual behaviours, crucially including mounting, in all but one male, but no effects were found on male faecal testosterone concentration. Thus, biologically-relevant scent enrichments have the potential to impact on conservation breeding and in the future this could be applied to other endangered species.
conservation, breeding, zoo, lemur, olfaction, enrichment, scent, behaviour, primate
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