Houlihan, P.W. 1989. Scent mounding by beaver (Castor canadensis): Functional and semiochemical aspects. M.S. Thesis, SUNY ESF, Syracuse, 184 pp.

Abstract: Multiple hypothesis testing was used to determine the most probable function of the scent moundingbehavior of beaver. Both original data and information from previous studies were used to test predictions from five of the proposed functions. Four of the chemical components (p -methoxyphenol, p - ethylphenol, acetophenone, 1, 2 - benzenediol) of beaver castoreum were tested in bioassays conducted with free-ranging beaver. The study was conducted from May to August, 1987 at Allegany State Park (ASP), New York and May to August, 1988 at Huntington Wildlife Forest, New York (HWF).

Several factors were considered which might influence the number of scent mounds found at 20 sites: family size, length of the perimeter of a site, site complexity, the number of active sites 5 km up-stream and down-stream and the distance to the nearest neighbor. Regression analyses were only significant for the last two factors.

Only the predictions for a territorial function of scent mounding were supported. A model of territorial defense via scent mounding is presented. Beaver scent mounds probably act both as a scent fence (deterring transient beaver from entering or remaining in a marked site) and are used as a means of assessment during interactions between resident and intruding beaver. A mechanism to account for the greater number of scent mounds at sites with a higher probability of intrusion is also presented.

A total of 225 trials were conducted at 14 sites at ASP and 7 sites at HWF. Both p - ethylphenol and p - methoxyphenol were behaviorally active. Males reacted more strongly to whole male castor and p - ethylphenol than females. Reactions at ASP tended to be stronger than at HWF. The limitations of the bioassay, as well as questions for future investigations, were discussed.