Inter- and intraspecific character displacement in mustelids

In a search for possible community-wide character displacement (manifested as equal size ratios between adjacent morphospecies in a size-ranking), examined the weasels (Mustela) of North America and also the mustelid-viverrid guild of Israel, measuring condylobasal skull length and maximal diameter of the upper canine. Results, plus information on feeding behavior, seem consistent with a hypothesis of competitive character displacement, but there is no direct evidence that prey are limiting to either guild, data are scant on what the morphospecies actually eat, and there is no functional analysis for these species of the role of canine or skull size in ability to kill prey of different sizes and types. Sexual selection based on canine display or fighting might well contribute to sexual dimorphism. Canines may be used in threats or fighting in interspecific encounters. However, it seems unlikely that such canine use could account for the entire pattern of size ratio equality, as it would be quite coincidental that size ratios sexually selected between sexes within species should happen to equal those, however selected, between the male of each species and the female of the next larger species. -from Authors