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YELLOWSTONE N. P.
GLACIER N. P.
WATERTON
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Present range
Estimated
historic range
NORTH AMERICAN DISTRIBUTION
OF WOLVERINES
(Gulo gulo)
western Canada. As predator poisoning was
phased out during the 1960s, wolverines from
the Canadian Rockies started to recolonize Mon-
tana’s high country and spread to parts of Idaho
and northern Wyoming.
Then, in the 1990s, wolverines from Canada
began venturing into Washington’s northern Cas-
cades. Today breeding groups live in four states:
Montana, Idaho, Wyoming, and Washington, but
the population remains small. A recent estimate
put the number of wolverines south of Canada
at around 300 animals.
Meanwhile, populations on both sides of the
U.S.-Canada border face a variety of threats. Most
come from expanding human activities in the
backcountry, but one concern overrides all others:
a warming climate. Gulo gulo is specially adapted
to, and highly dependent on, habitats with year-
round cool conditions and lingering snowpack.
Although polar regions are heating up faster than
other latitudes, similar temperature increases are
happening in the planet’s high altitudes, such as
the Rockies. If climate change continues as pre-
dicted, wolverines could lose one-third of their
present range south of Canada by 2050, and two-
thirds before the end of this century.
Since 1994, despite petitions and lawsuits
A wolverine in northern
Montana is one of only
about 300 living in the
contiguous U.S. Climate
change threatens to
isolate the vulnerable
population, but efforts
to protect it under the
Endangered Species
Act have stalled.
REALM OF THE WOLVERINE
Trapping and human settlement have shrunk wol-
verines’ historic range. Dependent on vast home
territories, they are scarce even in remote northern
forests and tundra regions, their primary habitat.
JOHN KAPPLER, NGM STAFF. SOURCES: KEITH AUBRY, U.S. FOREST SERVICE; ALASKA DEPARTMENT OF FISH AND GAME;
120 ENVIRONMENT CANADA, SPECIES AT RISK ACT: RECOVERY STRATEGY SERIES, 2016; BRIAN G. SLOUGH, WILDLIFE BIOLOGY, 2007