Reproductive endocrine patterns and volatile urinary compounds of Arctictis binturong: discovering why bearcats smell like popcorn

Abstract

Members of the order Carnivora rely on urinary scent signaling, particularly for communicating about reproductive parameters. Here, we describe reproductive endocrine patterns in relation to urinary olfactory cues in a vulnerable and relatively unknown viverrid--the binturong (Arctictis binturong). Female binturongs are larger than and dominate males, and both sexes engage in glandular and urinary scent marking. Using a large (n = 33), captive population, we collected serum samples to measure circulating sex steroids via enzyme immunoassay and urine samples to assay volatile chemicals via gas chromatography-mass spectrometry. Male binturongs had expectedly greater androgen concentrations than did females but, more unusually, had equal estrogen concentrations, which may be linked to male deference. Males also expressed a significantly richer array of volatile chemical compounds than did females. A subset of these volatile chemicals resisted decay at ambient temperatures, potentially indicating their importance as long-lasting semiochemicals. Among these compounds was 2-acetyl-1-pyrroline (2-AP), which is typically produced at high temperatures by the Maillard reaction and is likely to be responsible for the binturong's characteristic popcorn aroma. 2-AP, the only compound expressed by all of the subjects, was found in greater abundance in males than females and was significantly and positively related to circulating androstenedione concentrations in both sexes. This unusual compound may have a more significant role in mammalian semiochemistry than previously appreciated. Based on these novel data, we suggest that hormonal action and potentially complex chemical reactions mediate communication of the binturong's signature scent and convey information about sex and reproductive state.

Procyonidae, Viverridae, Hyenidae, Herpestidae, Eupleridae, and Prionodontidae

“…As an example, to some, binturongs smell like buttered popcorn. This specific odor has been attributed to a volatile compound in the urine (Greene et al, 2016). The use of anal-sac gland secretion from civets for musk scent in perfume is well documented, but it is also a welfare concern due to varying husbandry standards (Anonis, 1997;Klok and Nugteren, 1973;Tolosa and Regassa, 2007).…”

Microbial, proteomic, and metabolomic profiling of the estrous cycle in wild house mice

“…Another typical class of volatile organic compounds that stimulate the olfactory system of mammals are aliphatic ketones and they are often found in the odor of rodent urine ( 77 , 78 ). Among others, we detected 2-Pentanone, a highly abundant estrus marker in cervicovaginal mucus in bovine ( 79 ), and 2-acetyl-1-pyroline that mediates the communication of the binturong signature scent and conveys information about sex and reproductive state ( 80 ). In humans, 2-acetyl-1-pyroline was detected as one of the potential intravaginal odor-active compounds that may play a role in sperm chemotaxis ( 81 ).…”

Thinking with Civets: The Role of Zoos in the Decolonisation of Animal Tourism

“…Despite their crepuscular nature, binturong move around their enclosure and rest in full view of zoo visitors, and their activity patterns are unaffected by the presence or noise of spectators [4]. Their lack of direct relatedness to bears or cats makes for fun facts for enclosure signage, and their musk secretions give off a distinct pop-corn smell [5] for a multisensorial immersive zoo experience. Smell is an important sense for forming memories and arousing feelings [6], so odour may offer zoo education programmes an additional factor to contribute to long-lasting educational messages.…”