PR (Wolf 2020): 079 - Food habits and ecology of wolves on barren-ground caribou range in the Northwest Territories.

The food habits of tundra wolves were investigated mainly between 1960 and 1965, although some work continued until 1968. Studies were carried out in spring and summer in the Thelon Game Sanctuary,  Northwest Territories, with supplementary winter work on caribou winter range north of Yellowknife, Northwest Territories and east of Fort Smith.  Tag recoveries showed that tundra wolves may migrate over 200 miles and that their movements are associated with those of the barren-ground caribou. During the winter tundra wolves eat only caribou; during the spring and summer they vary their diet by eating small rodents, passerine birds, eggs and fish, particularly in areas temporarily devoid of caribou. Wolves prey on calves  more than other age classes of caribou, but caribou of over 8 years are also heavily preyed on. Wolves kill at least four times as many female caribou as males. Caribou killed in winter are completely utilized by wolves: in summer, parts of carcasses are often left to scavengers. The initial point of attack is the neck, and the caribou is pulled down or knocked down by the impact of the onrushing wolf. During maximum compression of wintering caribou populations, wolf densities of one wolf per 6.9 square miles were reached.
A captive wolf requires 3.23 pounds of bison meat and fat and 0.26 pounds of dog food daily. Mean growth curves illustrate the rapid early growth of cubs.