| Summary: | From September 2005 to March 2006 a zoo study was performed with one male and two female rhinos at Orana Wildlife Park in Christchurch. The study had two aims: (1) to assess whether faeces from unfamiliar rhinos carry information that influences the behaviour of adult rhinos in a zoo habitat, and (2) to identify olfactory constituents of the faeces that potentially stimulate the change in behaviour. Faeces samples were collected from seven male, female, and juvenile rhinos residing at Hamilton and Auckland zoos and from one male rhino held in a separate enclosure at Orana Park. From each sample type six individual samples of 2 kg each were collected. The samples were put in plastic bags and kept frozen at -1O℃. As controls, samples from peat, peat with testosterone, and heated faeces were used. An individual thawed sample was presented at a time to the subjects by placing it into the enclosure. Behaviour and positions of the subjects was monitored for 3 h. In addition weather data was collected. Each exposure test of one sample type consisted of at least six observation sessions during which one two-kg dung specimen was presented to the subjects in the Orana Park enclosure. Each session consisted of nine trial periods of 15 min, during which each subject was observed individually and all actions ofthe animal were recorded. There was a strong response of the subjects to faeces from male donors. The bull reacted with increased frequency of spray urinating. The bull habituated to the faecal stimulus within about an hour. Other strongly affected behaviour categories of all subjects included smelling the ground, scanning, and walking. The distance between the subjects and frequency of synchronous behaviour of the subjects was affected by various samples to a lesser degree. Correlation of faecal compounds with territorial behaviour activities and chemical analysis identified possible signalling compounds such as esters of low molecular weight fatty acids (propanoic, butanoic, and pentanoic acids) and perhaps testosterone and terpenoids. Even simulated control samples consisting of peat impregnated with testosterone initiated some response. Overall, faecal scent marks were found to stimulate multifaceted behavioural effects of captive white rhinoceros. Chemical analyses of faeces identified new olfactory components not previously attributed to male faeces, and which could act as male signalling compounds.
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