Anal sac

Buglass A., Darling F. and Waterhouse J. (1990). Analysis of the anal sac secretion of the Hyaenidae. In Chemical Signals in Vertebrates 5 (MacDonald D Miiller-Sehwarze D. and Natynczuk S.E., eds.). Oxford University Press, Oxford, pp. 65-69. 

Albone, E.S. and Perry, G.C. (1975) Anal sac secretion of the red fox, Vulpes vulpes volatile fatty acids and diamines Implications for a fermentation hypothesis of chemical recognition. J. Chem. Ecol. 2, 101-111. 

Only a few compounds or mixtures of compounds have been shown beyond doubt to be mammalian pheromones. This is the main reason why the subject matter of this chapter is not restricted to pheromones and why exocrine secretions and other mammalian excretions in general will be discussed as possible sources of pheromones, even though their role in the chemical communication of the species under discussion has not yet been established. Feeding deterrents are not discussed. In general defensive secretions are also not discussed, but the anal sac secretions of the mustelids are included, because it is possible that these secretions could also fulfill a semiochemical role, in addition to being used for defense. 

Bacterial activity has been shown to be responsible for volatile organic compounds in, among many others, the exocrine secretions of beavers (see above), the anal sacs of the red fox, Vulpes vulpes, and Hon, Panthera leo [85], and the inguinal pouch of the rabbit, Oryctolagus cuniculus [86]. No bacteria were, however, found in the anal gland of the European mole, T. europaea [87]. 

Albone [88] has reviewed the literature on anal sac secretions up to the early 1980s. Organosulfur compounds are particularly plentiful in many of these secretions and are responsible for their offensive odors. In general, predator odors seem to be repulsive to potential prey. Epple et al. [89] have speculated that the reason for the repellent properties of the feces and urine of carnivores could be diet related. It would be logical to argue that organosulfur compounds derived from a protein-rich diet could be a cue by which prey can distinguish a potential predator. The results so far are consistent with this hypothesis [90]. 

In contrast to the relatively limited number of organosulfur compounds in these species, the anal sac secretions of skunks contain large numbers of malodorous compounds, which are very effectively utilized in the defensive behavior of these species. During the early years of capillary gas chromatography, Andersen et al. [108] found that 150 of the 160 components detected in the anal gland secretion of the striped skunk, Mephitis mephitis, contained sulfur. The results of recent chemical studies on North American skunks by Wood et al. [109] are summarized in Table 4. Only three of the compounds reported in this table are common to the secretions of all four skunk species and, in two of these three secretions, the common compound is present in concentrations of about 1% or less. Although it is clear that skunks use their anal gland secretions primarily for defensive purposes, it does not rule out the possibility that the difference in the composition of these secretions could also be utilized for... 

Table 4 Quantitative composition of the volatile fraction of anal sac secretion from four species of North American skunks [109]a... 

In the secretions of the anal sacs of dogs [Canisfamiliaris) and coyotes (C. latrans) the most abundant volatile compounds are trimethylamine, short-chain (C2-C6 acetic, propionic, isobutyric) acids, acetone, and 2-piperidone (Preti etal, 1976). 

Svendsen and Jollick (1978) studied the microbes in the castor sacs and anal glands of the beaver, C. canadensis. No bacteria cultured from the castor sacs, while the anal sacs contained the aerobe Escherichia coli and the anaerobe Bacteroidesfragilis. Species and numbers of bacteria did not differ between the sexes, age classes, or beaver colonies. 

After a secretion has been produced, it can be stored for later use or even accumulated for massive or repeated signals. Anal sacs of canids, mustelids, and felids, and the castor sacs of beaver are examples. The skunk provides the most dramatic example for such reservoirs with large amounts of often very potent secretions. We do not understand well if and how the various compounds are transformed in these reservoirs. 

Another example from carnivores is the odor of anal sac secretion in the ferret, Mustelafuro. Ferrets discriminate strange from familiar individuals by this odor. (They also use anal sac secretion to distinguish males from females, a familiar individual s from own odor, and fresh from 1-day old odor, but not between fresh and odor only 2 hours old nor anestrous from estrous females [Clapperton etal., 1988]). 

The relative concentrations of constituents of the anal sac secretion in male stoats, Mustek erminea, are distinct for different individuals, but consistent over time for each individual. This possibly permits individual recognition of territory owners (Erlinge etal., 1982). The chemical composition of the anal gland of the otter, Lutra lutra (Gorman etal., 1978) and the subcaudal gland of the badger, Meles meles (Kruuk etal., 1984) also differ with the individuals. 

Ferrets, Mustek furo, distinguish between anal sac secretions of males and females. Males did not discriminate between the anal gland odors of estrous and anestrous females. Chemical sex differences were found, but no seasonal differences. Males had high concentrations of 2,3-dimethylthietane and/or 3,4-dimethyl-l,2-dithiolane (Fig. 7.6). Most individuals had 2-propylthietane. Clapperton etal. (1988) concluded that the odor of the anal gland provides sexual and territorial signals and cues to individual identity. 

FIGURE 10.9 Major sulfur compounds in the anal sac of the striped skunk Mephitis mephitis. (After Andersen and Bernstein [1975], Wood [1990], and Wood etal. [1991].)... 

The European rodents A. sylvaticus and Clethrionomys glareolus tend to avoid traps scented with 2,2-dimethylthietane from the anal sacs of the mink, Mustek vison, while it suppresses feeding in European wild rahhits, Oryctolagus cuniculus (Robinson, 1990). 

The introduced ferret, Mustelafuro, in New Zealand destroys native fauna and has to be controlled. For trapping, lures based on conspecific scent gland secretions or urine compounds can be as effective as food bait. Eight constituents of the anal sac secretion have been synthesized and tested for their ability to attract... 

Asa, C. S. (1993). Relative contributions of urine and anal sac secretion in scent marks of large fehds. American Zoologist 33,167-172. 

Brinck, C., Erlinge, S., and Sandell, M. (1983). Anal sac secretion in mustelids a comparison. Journal of Chemical Ecology 9,727-746. 

Preti G., Muetterties, E. L. Furman, J. M., Kennedy, J. J., and Johns, B. E. (1976). Volatile constituents of dog [Canis familiaris) and coyote [Canis latrans) anal sacs. Journal of Chemical Ecology 2,177-186. 

White, P. J., Kreeger, T. J., Tester, J. R., and Seal, V. S. (1989). Anal-sac secretions depos ited with feces by captive red foxes (Vulpes vulpes).Journal of Mammalogy 70,814-816. 

A 15-membered ring macrolide, 4-tetradecen-14-olide (Fig. 32,185), has been reported as an anal sac secretion of striped hyena Hyaena hyaena, and it may be used to mark territorial boundaries [204]. Ambrettolide (130) is a 17-membered ring macrolide produced by plants and insects (see Sections V.B and VI.A). It is also detected in the lipid from musk of muskrat Ondatra zibethica [205]. 

Vasilieva, V. S., Roznov, V. V., and Zinkevich, E. P., 1980, Secretion and secretory tissues of the anal sac of the mink, Mustela vison. Chemical and histological studies, J. Chem. Ecol., 6 805. 

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