The Effect of a Synthetic Scent on Cheetah Behaviour

SIMPLE SUMMARY: Up to date, little is known about the role of semiochemicals in cheetahs. Scientists have speculated that the concentration of VOCs potentially involved in breeding behaviour could be present at low concentrations since cheetahs’ urine emits very little odour. Therefore, the effect of a synthetic scent has been tested on female cheetahs (Acinonyx jubatus) behaviour with the objective of possibly increasing the frequency of reproductive (e.g., precopulatory and copulatory) behaviour displayed by female cheetahs. Furthermore, this study aimed at investigating the function of semiochemicals in reproduction in this species. The study indicates that volatile organic chemicals (VOCs) have an effect on cheetahs and their behaviour; however, additional research is required to determine the effects of specific VOCs on cheetah reproduction. “Fine tuning” of the synthetic scent could potentially aid in improving captive breeding, as well as preventing asymmetric reproductive ageing. ABSTRACT: In cheetahs, age at first parturition correlates negatively with reproductive lifespan (asymmetric reproductive aging); therefore, breeding cheetahs at a young age is essential to maximize reproductive performance in this species. However, younger females display a significantly reduced frequency of copulatory behaviour, which negatively affects breeding. Volatile organic compounds (VOCs) are known to regulate appropriate behavioural responses in various species, including reproductive behaviour; moreover, they have proven to play a role in captive breeding methods in cheetahs, as well as mate choice. Therefore, the objective of this study was to evaluate the effect of a synthetic scent (SS) on the frequency of the five oestrous behaviour(s) (sniff, rub, roll, spray, and meow-chirp) known to be indicative of oestrus in female cheetahs. Based on the results of a previous study from our research group, five VOCs, identified in the marking fluid of male cheetahs, and known to be pheromones involved in reproductive behaviour, were used to create the SS. This was accomplished by mixing benzaldehyde, acetophenone, indole, dimethyl disulphide and phenol with (99.9%) ethanol. Seven female cheetahs were then observed for one oestrus cycle without stimulation (control) and then once again while exposed to the SS (treatment), which was sprayed on foil trays placed around the outside of each enclosure. The occurrence of the five oestrous behaviours was recorded and tallied per day of observations. Although the SS did not have a significant effect on the frequency of oestrous behaviours displayed by the females used in this study, five of the seven (71%) did show an increase in their behaviour with the SS when oestrogen concentrations were at their highest (peak oestrus), including three of the four younger females. The SS also significantly increased the sniffing behaviour in general. Although the results of this study do indicate that VOCs influence cheetahs and their behaviour, firm conclusions cannot be drawn due to the low number of animals used, as well as the significant effect the observation methods had on the results. Nonetheless, this study represents the first of this kind in cheetahs, therefore representing an important step in determining the role of VOCs in aiding breeding in captivity.