Volatile scent chemicals in the urine of the red fox, Vulpes vulpes

Abstract

The red fox is a highly adaptable mammal that has established itself world-wide in many different environments. Contributing to its success is a social structure based on chemical signalling between individuals. Urine scent marking behaviour has long been known in foxes, but there has not been a recent study of the chemical composition of fox urine. We have used solid-phase microextraction and gas chromatography-mass spectrometry to analyze the urinary volatiles in 15 free-ranging wild foxes (2 female) living in farmlands and bush in Victoria, Australia. Foxes here are routinely culled as feral pests, and the urine was collected by bladder puncture soon after death. Compounds were identified from their mass spectra and Kovats retention indices. There were 53 possible endogenous scent compounds, 10 plant-derived compounds and 5 anthropogenic xenobiotics. Among the plant chemicals were several aromatic apocarotenoids previously found in greater abundance in the fox tail gland. They reflect the dietary consumption of carotenoids, essential for optimal health. One third of all the endogenous volatiles were sulfur compounds, a highly odiferous group which included thiols, methylsulfides and polysulfides. Five of the sulfur compounds (3-isopentenyl thiol, 1- and 2-phenylethyl methyl sulfide, octanethiol and benzyl methyl sulfide) have only been found in foxes, and four others (isopentyl methyl sulfide, 3-isopentenyl methyl sulfide, and 1- and 2-phenylethane thiol) only in some canid, mink and skunk species. This indicates that they are not normal mammalian metabolites and have evolved to serve a specific role. This role is for defence in musteloids and most likely for chemical communication in canids. The total production of sulfur compounds varied greatly between foxes (median 1.2, range 0.4–32.3 μg ‘acetophenone equivalents’/mg creatinine) as did the relative abundance of different chemical types. The urinary scent chemistry may represent a highly evolved system of semiochemicals for communication between foxes.

Heat induces multi-omic and phenotypic stress propagation in zebrafish embryos

“…Organosulfur compounds may function as cues in chemical ecology, for instance in fox urine (50) and cat urinary pheromones (51), and therefore warrant further study.…”

Behavioral differences among domestic cats in the response to cat-attracting plants and their volatile compounds reveal a potential distinct mechanism of action for actinidine

“…Another molecule that is structurally different from type I and II lactones (as well as actinidine) is dihydroactinidiolide ( Figure 12 ), which contains a furanone ring (5 membered lactone) compared to pyranone rings (6 membered lactone). Interestingly, unlike the compounds 1 – 9 tested in this study that have only been detected in plants or insects, dihydroactinidiolide has additionally been detected in glandular secretions and urine of the red fox (McLean, Nichols and Davies 2021, Albone 1975, McLean, Davies and Nichols 2017). None of the other iridoids tested here are produced or secreted by a mammal to our knowledge.…”

Chemical Characterization of the Marking Fluid of Breeding and Non-Breeding Male Cheetahs

“…These VOCs, in fact, increased during the proestrus and estrus stage of the estrous cycle while other foul-smelling sulfureous VOCs decreased, which indicates the attracting effects of the VOCs during proestrus and estrus, as well as the potential repulsive effect of the other sulfureous VOCs during diestrus [ 43 ]. Acetophenone excretion is also higher in female wolves than intact males [ 44 ], and benzaldehyde is also known to be involved in influencing sexual behavior in lemurs, thereby functioning as a sex pheromone [ 45 ].…”