Lemmings

Lemmings are among the most numerous small rodents in the Canadian Arctic, and their startling reproductive capacity makes them more than a seasonal nuisance: their abundance rises and falls in a recurring cycle that can shape the conditions faced by predators and other wildlife. The account replaces a popular caricature of lemmings with an ecological portrait of prolific animals whose numbers can surge, then nearly disappear.

Seasonal Abundance and Human Encounters

As June waned into July, the country seemed to fill with small rodents. Lemmings were the most numerous species, and their capacity to reproduce, rather than the familiar story of supposedly suicidal behavior, was what stood out. Red-backed and meadow mice also invaded Mike’s cabin in such numbers that the researcher feared losing his food supplies. They ate his bread, and one meadow mouse gave birth to eleven young inside the pillow of his sleeping bag. The episode makes the rodents’ increase tangible: it reached from the bogs into the cabin and even into the place where he slept.

The researcher’s subsequent mouse survey was designed to measure the population rather than rely on impressions. He set about 150 traps in a nearby bog to obtain a representative sample by sex, age, density, and species. The location seemed convenient and typical of ground hunted by wolves, but the second day George appeared in that direction. Ten traps had been placed near the burrows of a lemming colony, and George walked toward them. The scene connects the effort to study small-rodent populations with the animals’ place in a landscape also used by predators, though the account here does not establish what George did at the traps.

A Food Source in a Wider Diet

The rodent surge helped overturn the researcher’s assumptions about how wolves could remain well fed while apparently bringing no large prey back to the den. Watching Angeline hunt, he eventually saw her catch and eat twenty-three mice; he later concluded that the wolves at Wolf House Bay, and by inference other Barren Land wolves raising families beyond the summer caribou range, lived largely or almost entirely on mice. The evidence supports a central role for small rodents in the wolves’ diet, but it does not establish that lemmings alone supplied that food: the account discusses mice broadly and identifies lemmings as the most numerous of the small rodents.

Other evidence broadens the picture of rodent consumption without identifying lemmings specifically. In an analysis of wolf scat, about 48 percent of samples contained rodent remains, largely teeth and fur; the other identifiable materials included caribou remains and bird feathers. Together, these observations show why the researcher’s view of wolf feeding changed from an expectation centered on large game to an understanding that small prey could sustain wolves. They do not, however, assign the rodent remains in the samples to a particular species.

The Four-Year Cycle

In the Canadian Arctic, lemmings are described as a cyclic species: their abundance peaks every four years, then falls almost to zero. This recurring rise and collapse makes their importance different from that of a consistently available food source. A plentiful year can bring a dense supply of small mammals; a low year can remove that resource from the landscape on a wide scale.

The account places lemming abundance within a broader pattern of animal reproduction and food availability. It describes wolf litter size as varying with the availability of food species, while rough-legged hawks may lay five or six eggs when small mammals are plentiful but only one, or none, when mice and lemmings are scarce. The comparison presents small-rodent fluctuations as conditions to which different animals respond, rather than as an isolated feature of lemming life.

The Low Point of 1946

In 1946, lemmings were at the low point in their cycle. That scarcity coincided with a sharp disruption elsewhere in the food system: depleted caribou herds in Keewatin changed their longstanding migration pattern, and most bypassed southern central Keewatin. The combined shortage made the season disastrous for people, foxes, and wolves. The account reports that rabies, latent among starving foxes, flared up and that wolves also began contracting the disease.

The episode gives the four-year cycle its starkest consequence in the narrative. Lemming numbers did not act alone: the caribou’s altered migration compounded the shortage. But their cyclical collapse forms part of the explanation for why hunger became widespread in that year, showing how a small rodent’s population rhythm could matter far beyond the bogs where the animals lived.