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


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.

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We would like to thank the Carnivore Preservation Trust (now the Carolina Tiger Rescue), in particular Kathryn Bertok, for their collaboration in this project and for the excellent care provided to the animals. We thank Joseph Petty and Jillian Wisse for their technical assistance with validating the endocrine assays. The assistance of Qin Yin and Innocent H. Harelimana with the GC-MS data analysis is greatly appreciated. Funds were provided by an Undergraduate Research Support grant from Duke University (to LKG) and by National Science Foundation grant, IOS-1021633 (to CMD). Financial support at Hendrix College was provided via a Distinguished Professor grant, the Odyssey Program, and John and Laura Byrd (to TEG).

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Correspondence to Christine M. Drea.

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The animals were maintained in accordance with the NIH Guide for the Care and Use of Laboratory Animals.

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Communicated by: Sven Thatje

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Greene, L.K., Wallen, T.W., Moresco, A. et al. Reproductive endocrine patterns and volatile urinary compounds of Arctictis binturong: discovering why bearcats smell like popcorn. Sci Nat 103, 37 (2016).

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  • Female dominance
  • Olfactory communication
  • Urinary signals
  • Reproductive endocrinology
  • 2-Acetyl-1-pyrroline
  • Viverrid