A COMPARISON OF SPONTANEOUS AND ODOR-INDUCED CHIN MARKING IN MALE ANDFEMALE DOMESTIC RABBITS (ORYCTOLAGUS-CUNICULUS DOMESTICA)

Chin marking by the European rabbit (Orytolagus cuniculus) is one of t he classic but still little understood examples of mammalian mammalian chemical communication. To investigate whether the sexes differ in pe rformance of this behavior, we compared the frequency of spontaneous c hinning and chinning in response to the chin marks of conspecifics in 20 intact male and 20 intact female chinchilla-breed rabbits, and in f ive gonadectomized animals of each sex. Contrary to the expectation of greater chinning activity in males, no significant sex differences we re found. Frequencies of spontaneous chinning were similar in the two sexes, large and stable individual differences were observed in both, chinning increased in both when marks from unfamiliar conspecifics wer e present, and both directed chin marks to objects marked by conspecif ics more than to unmarked objects. Individual chinning frequencies cor related positively with urination but not defecation in both sexes, an d spontaneous and odor-induced chinning were significantly reduced bot h in castrated and ovariectomized animals. The findings suggest that c hinning is an equally significant part of the communication system of male and female rabbits and that its expression may be regulated by si milar olfactory, hormonal, and social mechanisms.