Contribution of anal scent gland and urinary odorants to mate recognition in the ferret

Abstract

Previous research [J. Neurosci. 21 (2001) 5832-5840] showed that ferrets of both sexes require olfactory signals to identify opposite-sex mating partners at a distance. The present experiments assessed the contributions of anal scent gland and urinary odorants to these preferences. Sexually experienced, ovohysterectomized female and castrated male ferrets were injected daily with estradiol benzoate and testosterone propionate, respectively. When tested in an airtight Y-maze, subjects of both sexes preferred to approach volatile odors emitted from opposite- versus same-sex stimulus ferrets that were anesthetized and placed in the goal boxes, regardless of whether the anal scent glands of stimulus ferrets had been surgically removed or left intact. Subjects of each sex showed an equal preference to approach volatile odors emitted from anesthetized opposite-sex ferrets that were scent-gland intact as opposed to descented. Female subjects preferred to approach volatile anal scent gland odorants, as well as urinary odorants from male, as opposed to female conspecifics. Male subjects preferred to approach volatile anal scents from females versus males; however, males showed no preference for female over male urinary odorants. Our results suggest that anal scent gland odorants are sufficient, but not required, for mate recognition in the ferret. Instead, a combination of body odorants including, but not restricted to, those derived from anal scent gland secretions apparently underlie olfactory sex discrimination and partner preference in this carnivore.

Bilateral damage to the sexually dimorphic medial preoptic area/anterior hypothalamus of male ferrets causes a female-typical preference for and a hypothalamic Fos response to male body odors

“…In other studies gonadectomized male and female ferrets that were primed with testosterone and estradiol, respectively, showed a strong preference to approach volatile body odors emitted from anesthetized opposite-sex ferrets [16] as well as volatile anal scent gland odorants from opposite-sex ferrets [11] in Y-maze tests. Female subjects also showed a preference to approach urinary odors from males, although male subjects failed to show a strong preference to approach female urinary odors in Y-maze tests [11].…”

“…Daily test sessions were comprised of eight free trials and seven guided trials (a total of 24 free trials and 21 guided trials over the three days per stimulus condition). After subjects made a choice to run to particular anesthetized stimulus ferrets in each trial, the goal box door was lifted and the subject was allowed to make nasal contact with the stimulus for 5 s, as in our previous study [11]. We reasoned that such direct contact would lead to an activation of VNO inputs, which would enhance the reward salience of the particular suite of odor stimuli emitted from male vs. female stimulus ferrets.…”

“…Animals received three separate series of tests for their preferences to approach the goal boxes containing the following olfactory stimuli: body odors emitted from anesthetized male vs. female stimulus ferrets; odors emitted from male vs. female anal scent gland secretions; and odors emitted from male vs. female urine, exactly as described previously [11]. Breeding male and female stimulus ferrets were anesthetized with a combination of xylazine (4 mg/kg) and ketamine (35 mg/kg) prior to being placed into separate goal boxes.…”

“…We reasoned that such direct contact would lead to an activation of VNO inputs, which would enhance the reward salience of the particular suite of odor stimuli emitted from male vs. female stimulus ferrets. Tests of animals' preferences to approach anal scent and urinary stimuli only included 'free trials' (8 per day for 3 days) in so far as a previous study [11] suggested that ferrets of both sexes showed a sex-typical preference for these odorants in Y-maze tests in the absence of any 'guided trials'. Also, in the present study subjects were never allowed to gain direct physical access to anal scent gland and urinary stimuli after each trial.…”

Wired on Steroids: Sexual Differentiation of the Brain and Its Role in the Expression of Sexual Partner Preferences

“…Heterosexual partner preference is eliminated in anosmic male and female ferrets even when the subjects were able to see, hear and interact physically with stimulus ferrets in a Y-maze (Kelliher and Baum, 2001). Additional experiments have established an obligatory role of olfactory cues in ferret heterosexual partner preference (Cloe et al, 2004; Woodley and Baum, 2004). Existing evidence suggests that a sex dimorphism in the detection of odorants by the main olfactory system as well as the central processing of pheromonal cues play central roles in mate recognition in ferrets (Baum, 2009).…”