Olfactory communication and social behaviour in the mink (Mustela vison)
This thesis is about olfactory communication in mink (Mustela vison) and how it may relate to their social behaviour. The sources of mammalian social odours and studies of scent marking by carnivores were discussed. The possible functions of scent marking in territories were also discussed, with particular reference to Gosling's scent matching hypothesis. The distribution of faeces (scats) in a coastal population of mink was ddtermined on a monthly basis. Most scats were found in the months December to April, which includes the mating season. Although scats tended to occur singly, they had a clumped distribution because single scats tended to be deposited around certain features in the enviornment. Scats were found around the same features over a number of months. The areas where scats were deposited also tended to have a clumped distribution when data from all months were considered. A trained male mink was able to discriminate between the faeces of mink irrespective of their sex or degree of association with the experimental animal. Over a 48 hour period, male mink over-marked faecal samples from other mink with their own faeces. Females normally only over-marked faeces from females kept in neighbouring cages. During lactation and in August and September the females over-marked faeces from unknown males and females. When testing the immediate response of mink to faeces, both male and female mink spent more time sniffing at faeces from other mink than at their own faeces. Males also spent more time sniffing at faeces from females during the reproductive period than they did outside the reproductive period. During their immediate response to faeces, the males tended to produce trails of urine on top of or beside samples of faeces from unknown males and females. While in reproductive condition, mink spent more time sniffing and produced more urine trails in response to samples of urine collected from females that were likely to be in oestrus than at samples collected from females unlikely to be in oestrus. Outside the reproductive period both males and females produced urine trails in response to urine from unknown males and females. Male mink produced more scent marks in response to samples of old (24 hours) anal sac secretion than to fresh anal sac secretion. Female mink produced few scent marks in response to either sample. Anal sac secretion when sprayed from a model mink, caused both mink and potential predators of mink, to back away from the model. The presence of the major constituent of the anal sac secretion, 2,2-dimethylthietane was shown to reduce the 'trapability' of mink and small rodents, and to cause feeding suppression in rabbits over a 24 hour period. Experiments designed to test predictions of Goslings hypothesis could not support or refute the hypothesis.