Volatile compounds from the forehead region of male white-tailed deer (Odocoileus virginianus)

Secretions produced by sebaceous and apocrine glands of cervids may be important in identifying individuals, establishing dominance, and signaling sexual readiness. The secretions from these glands are transferred to the hair for both lubrication and scent communication via forehead rubbing. We collected hair samples from the forehead and back of 10 male white-tailed deer (Odocoileus virginianus) of various ages and analyzed them with gas chromatography-mass spectrometry to determine age-related differences. Fifty seven compounds were identified, including alkanes, arenes, aldehydes, ketones, aliphatic alcohols, terpenes, terpene alcohols, and phenols. Although forehead apocrine glands of dominant deer become more active during the breeding season, we found that concentrations of eight compounds found on the forehead hair were higher in subordinate deer, while only one was higher in dominant deer. Subordinate deer may have higher concentrations of these compounds because they rub less frequently than dominant deer. Additionally, only five forehead hair volatiles differed in concentration from those taken from the back hair. This seems to indicate that an increase in forehead glandular activity may take place concurrently with an increase in general integumentary glandular activity. The variation in hair volatiles among individuals also may be indicative of an individual-specific odor that could aid in identification.