Wolverine natal dens are excavated in snow, often several metres of it, sometimes incorporating fallen trees or boulder fields as structure. Kits are born in February or March, and the den must hold together until they are mobile. The requirement is not simply cold but depth and persistence: snow still present into the spring melt period.
This dependence is measurable at continental scale. Analyses matching wolverine occurrence records against satellite-derived spring snow cover found that the species' range across North America corresponds closely to areas holding snow into mid-May, and the same relationship holds in Eurasia. The correspondence is close enough that spring snow persistence works as a habitat model on its own.
Wolverines are also formidable eaters, which is where the name Gulo gulo, glutton twice over, comes from. They cache meat in cold ground and snow, crush frozen bone with heavy premolars and travel very long distances between carcasses. What is not settled is the mechanism behind the snow relationship: whether the snow is needed chiefly for den structure, for thermal protection, for concealment from predators, or for keeping cached food frozen. Those explanations have not been separated.