Brown bear skin-borne secretions display evidence of individuality and age-sex variation

Abstract

Scent originates from excretions and secretions, and its chemical complexity in mammals translates into a diverse mode of signalling. Identifying how information is encoded can help to establish the mechanisms of olfactory communication and explore the use of odours as chemical signals. Building upon existing behavioural and histological literature, we sought to examine the chemical profile of secretions used for scent marking by a solitary, non-territorial carnivore, the brown bear (Ursus arctos). We investigated the incidence, abundance, and uniqueness of volatile organic compounds (VOCs) from cutaneous glandular secretions of 12 wild brown bears, and assessed whether age-sex class, body site, and individual identity explained profile variation. The average number of compounds varied by age, but not solely by sex or body site. VOC profiles varied in composition and structure by age and individual identity (when individuals were grouped by sex), but not solely by sex or body site. Individual compound uniqueness varied by body site and age for both males and females and across individuals. Our results indicate that brown bear skin-borne secretions may facilitate age-sex class and individual recognition, which can contribute towards further understanding of mating systems and social behaviour.