Burrowers
|Limiting factors
How common suitable sites for burrowing are, influences both the distribution of burrows, and the frequency with which new burrows are excavated.
Wolf in the Yukon has the largest home range of any carnivore (13 000 km2. Throughout the larger part of the year, packs of wolves follow the migrations of caribou. The pups are reared in a burrow. So imperative is underground denning during this period that wolves stop their migration and seek suitable places for burrowing. Such places are scarce in the tundra. For this reason, wolves return year after year to the same sand ridges, which are pockered with burrows. Not only are the burrows concentrated, but the individual holes tend to be reused for hundreds and thousands of years (e.g. Stephenson 1974).
