What If Gone

Species → Wolverine

Wolverine

Gulo gulo

More than 10,000 mature individuals in Canada alone — but with a…
Extinction risk Least Concern
PredatorBoreal forestClimate changeScientific controversy
Wolverine (Gulo gulo)
Photo: Esquilo, Wikimedia Commons (CC BY-SA 3.0)

What if it disappeared?

Impact Moderate
Over 6 years, Fennoscandia/North America

Of 562 reproductive dens recorded across Fennoscandia and North America, 97.9% were located at sites where snow cover persisted in at least one of seven years through mid-May — establishing durable spring snow as an almost universal requirement for wolverine reproduction.

Documented
Detail

Copeland, J.P. et al. (2010). The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution? Canadian Journal of Zoology, 88(3), 233–246.

The study compiles all verified known dens over the period: 65 in North America, 10 in Finland, 327 in Norway (2000-2006), and 160 in Sweden (2003-2006), compared against a satellite map of persistent snow cover. Snow at least one meter deep late into spring provides thermal insulation protecting the young — a link so consistent that it long served to project the species' future range contraction under warming.

Later, Sweden

Since then, the wolverine has recolonized boreal forests in Sweden located outside the persistent-snow range predicted by the original model — challenging the idea that spring snow is a strict physiological constraint, rather than simply a correlation inherited from a history of persecution that had confined the species to alpine refuges.

Extrapolated
Detail

Persson, J., Ordiz, A., Ladle, A., Andrén, H. et Aronsson, M. (2023). Recolonization following past persecution questions the importance of persistent snow cover as a range limiting factor for wolverines. Global Change Biology, 29, 5802–5815.

By revisiting two decades of reproductive data in Sweden, the authors show the species now breeds successfully in boreal forest landscapes without persistent snow cover — suggesting the historical correlation observed by Copeland and colleagues mainly reflected where the wolverine had survived hunting, not where it could biologically live.

What's missing to confirm it: An equivalent reassessment in other historically hunted regions, to determine whether this pattern of recolonization outside persistent snow generalizes beyond the Swedish case alone.

Not measured to date

Despite its role as a scavenger and small predator in boreal and arctic ecosystems, no study identified measures what its disappearance would change for the prey populations or carrion availability it exploits — available literature covers its habitat requirements, not its functional role in the food chain.

Insufficient

Documentation

Last verified: August 14, 2026