The Ecology of Snowshoe Hares in

Abstract—Snowshoe hares exhibit eight to 11 year population fluctuations across boreal North America, typically with an amplitude of 10 to 25 fold. These fluctua-tions are synchronous across the continent, with the most recent peak densities occurring in 1990 and 1991. The numeric cycle is driven by changes in survival and reproduction, with annual survival of adults ranging from approximately five to 30 % and annual natality ranging from approximately six to 20 leverets/female. These parameters show cyclic changes because of functional and numerical re-sponses of predators and changes in food supply. Predator densities show approxi-mately two to 10 fold fluctuations during the hare cycle. The cyclicity of hares may be partly explained by regular behavioral shifts, with repercussions on their physiology, availability to predators, reproduction, and survival. However, this hypothesis needs more empirical support before it can be accepted