Scent beaver

Benzoic acid in the free state, or in the form of simple derivatives such as salts, esters, and amides, is widely distributed in nature. Gum benzoin (from styrax ben in) may contain as much as 20% benzoic acid in the free state or in combinations easily broken up by heating. Acaroid resin (from anthorrhoca haslilis) contains from 4.5 to 7%. Smaller amounts of the free acid are found in natural products including the scent glands of the beaver, the bark of the black cherry tree, cranberries, pmnes, ripe cloves, and oil of anise seed. Pern and Tolu balsams contain benzyl benzoate the latter contains free benzoic acid as well. The urine of herbivorous animals contains a small proportion of the glycine derivative of benzoic acid, hippuric acid [495-69-2] (CgH CONHCH2COOH). So-called natural benzoic acid is not known to be available as an item of commerce. 

Recently, Rosell and Sundsdal [78] tentatively identified 21 of the 43 constituents present in 96 scent marks deposited directly on snow or ice mounds by the Eurasian beaver, C. fiber. In this study, a higher final oven temperature was employed and several steroids were eluted from the capillary column. Because the main focus of this study was to determine whether the beaver uses castoreum and/or anal gland secretion for scent marking and not the full chem-... 

The anal gland secretion of beaver, C. canadensis, differs between the sexes (Gr0nneberg, 1978-79). The male grey duiker, Sylvicapra grimmia, has more 2-heptanone and 2-nonadecanone in its preorbital secretion than the female. Two thiazoles (2-isobutyl-1,3-thiazole and 2-isobutyl-4,5-dihydro-l,3-thiazole) and an epoxy ketone (3,4-epoxy-2-dodecanone) are also more abundant in the male s secretion. Correlated with these chemical differences is the fact that only males scent mark with the preorbital gland (Burger etal., 1990). 

Beaver Castor canadensis Differential response to scent marks of relatives and strangers, phenotype matching Sun and Miiller-Schwarze, 1997... 

Unlike most terrestrial mammals, beavers maintain territories along a line following watercourses. Both species, the Eurasian beaver, C. fiber, and the North American beaver, C. canadensis, dredge up mud from the bottom of their home pond, carry it on land, deposit it, and apply a scent mark on top of this mud... 

FIGURE 6.10 A giant beaver scent mound. (Vertical kitchen knife, center, for scale). (Photograph D. Muller-Schwarze.)... 

It is less likely that beavers will colonize unoccupied beaver sites if these sites are artificially scented with castoreum and anal scent secretion (Welsh and Muller-Schwarze, 1989). 

FIGURE 6.12 Correlation between population density and scent marking intensity in the beaver. Castor canadensis. (From Houlihan, 1989.)... 

If artificial castoreum scent marks are placed on the banks of a pond, beavers, C. canadensis, are more likely to visit, destroy, and re-mark the sites as the complexity of the artificial odor composition increases (Fig. 6.14). While some single phenolics from castoreum such as 4-ethylphenol trigger marking (Miiller-Schwarze and Houlihan, 1991), the response increases as the mixture grows to 4, 6,10,13, and finally 15 compounds. A mixture of 14 phenolics and 12 neutrals (mostly oxygenated monoterpenes) released responses almost as strong as whole castoreum (Schulte etal., 1995). 

FIGURE 13.2 Beavers colonized only 2 of 47 (4%) experimentally scented potential colony sites (left), but 8 of 49 (16%) unscented control sites (right). Black indicates colonized sites cross-hatched, sites left vacant. Fulton County Experiment. (FromMuller-Schwarze 1990.)... 

Scents from coyotes, foxes, and other carnivores traditionally have served to attract these animals to traps. Trappers also use conspecific secretions to attract beavers, raccoons, and other fur bearers to traps. The use of scent lures in predator control is discussed below. 

Mountain beaver, Aplodontia rufa, a primitive rodent from northwestern North America, fed less from food bowls if the rim was scented with mink anal gland secretion, or urine from mink, bobcat, coyote, or dog. The control odors butyric acid or guinea pig urine had no effect (Epple et fl/., 1993). Mountain beaver did not respond significantly to mustelid sulfur compounds though, yet these deter other small mammals (Epple etal, 1993). 

Bollinger, K. S. (1980). Scent marking behavior of beaver (Castor canadensis) M. Sc. Thesis, University of Massachusetts, Amherst. 

Rosell, F., Bergan, F., and Parker, H. (1998). Scent marking in the Eurasian beaver [Castor fiber) as a means of territory defense. Journal of Chemical Ecology 24, 207-219. 

Svendsen., G. E. (1980). Patterns of scent-mounding in a population of beaver [Castor canadensis). Journal of Chemical Ecology 6,133-148. 

Welsh, R. G. and Miiller-Schwarze, D. (1989). Experimental habitat scenting inhibits colonization by beaver, Castor canadensis. Journal of ChemicalEcology 15,887-893. 

Castoreum or caster is a strongly scented creamy fluid derived from the genitals of male beavers. This name is also applied to similar materials taken from otters and muskrats. These fluids are used by the animals to mark their territories and to attract females. They are reputed to have the same effects on other species, notably humans, when incorporated into perfumes or creams. Castoreum perfume is produced by placing the entire gland into alcohol. 

Scent Marking in Free-Ranging Mammals. Examples Beaver or Badger... 

Left an unusually large scent mound buUt by beavers. Right Application of a scent sample to the cork on an experimental scent mound... 

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