Effects of scent enrichment on behavioral and physiological indicators of stress in zoo primates

Captive breeding is vital for primate conservation, with modern zoos serving a crucial role in populations of threatened species and educating the general public. However, captive can experience welfare issues that may also undermine their reproductive success. To enhance wellbeing endangered zoo primates, we conducted study to assess effects new scent enrichment program on red-ruffed lemurs (Varecia rubra), black howler monkeys (Alouatta caraya), siamangs (Symphalangus syndactylus), lar gibbons (Hylobates lar) orangutans (Pongo pygmaeus pygmaeus). We combined behavioral observations fecal endocrinology analyses evaluate series essential oils (benzoin, lavender, lemongrass) five troops (N = 19) housed at Dudley Zoo & Castle Twycross (UK). recorded natural species-specific abnormal stress-related behaviors 480 h using instantaneous scan sampling. collected 189 samples measured cortisol concentrations radioimmunoassay. found significant effect behaviors, reducing social interactions, as well decreasing after they were exposed oils. displayed increase glucocorticoids following exposure Our contradictory findings suggest this change depending lives olfactory repertoires primates. In conclusion, cannot recommend these widely primates without additional evaluation.