Northern populations of snowshoe hares undergo cycles that range from seven to 17 years between population peaks.
The average time between peaks is approximately 10 years.
The period of abundance usually lasts for two to five years, followed by a population decline to lower numbers or local scarcity.
Areas of great abundance tend to be scattered.
Populations do not peak simultaneously in all areas, although a great deal of synchronicity occurs in northern latitudes.
From 1931 to 1948, the cycle was synchronized within one or two years over most of Canada and Alaska, despite differences in predators and food supplies.
In central Alberta, low snowshoe hare density occurred in 1965, with 42 to 74 snowshoe hares per 100 acres (40 ha).
The population peak occurred in November 1970 with 2,830 to 5,660 snowshoe hares per 100 acres (40 ha).
In the southern parts of its range, snowshoe hare populations do not fluctuate radically.

Exclosure experiments in Alberta indicated browsing by snowshoe hares during population peaks has the greatest impact on palatable species, thus further reducing the amount of available foods.
In this study, insufficient nutritious young browse was available to sustain the number of snowshoe hares present in the peak years (1971 and 1972) in winter.

The hare's fluctuating numbers are modelled by the Lotka-Volterra equations.
Northern populations of snowshoe hares undergo cycles that range from seven to 17 years between population peaks. The average time between peaks is approximately 10 years. The period of abundance usually lasts for two to five years, followed by a population decline to lower numbers or local scarcity. Areas of great abundance tend to be scattered. Populations do not peak simultaneously in all areas, although a great deal of synchronicity occurs in northern latitudes. From 1931 to 1948, the cycle was synchronized within one or two years over most of Canada and Alaska, despite differences in predators and food supplies. In central Alberta, low snowshoe hare density occurred in 1965, with 42 to 74 snowshoe hares per 100 acres (40 ha). The population peak occurred in November 1970 with 2,830 to 5,660 snowshoe hares per 100 acres (40 ha). In the southern parts of its range, snowshoe hare populations do not fluctuate radically.
Exclosure experiments in Alberta indicated browsing by snowshoe hares during population peaks has the greatest impact on palatable species, thus further reducing the amount of available foods. In this study, insufficient nutritious young browse was available to sustain the number of snowshoe hares present in the peak years (1971 and 1972) in winter.
The hare's fluctuating numbers are modelled by the Lotka-Volterra equations.
Snowshoe hare