SNOWSHOE HARE
Occupying a lower rank of the forest
food chain — a meal for lynx, foxes,
coyotes, and birds of prey — the
snowshoe hare must hide to survive.
Its coat changes from brown during
warm months to bright white in winter
to match the snowy landscape. This
camouflage, however, is becoming less
effective as the planet warms. When
snow arrives late and melts early, the
hares end up “mismatched” to their
surroundings — think bright white on
a dark forest floor of dirt and leaves —
making them extra vulnerable to preda-
tors. (Researchers in Montana have seen
mismatched hares die at a rate seven
percent higher than those that blend
into their environment.) In response,
the animals are moving to colder climes.
While the effect is not yet profound,
WWF’s Advani says it’s just a matter of
time: “They’re pretty maladapted.”
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MONARCH BUTTERFLY
HABITAT North America, Hawaii, Portugal, Spain,
Australia, New Zealand, and elsewhere in Oceania
THREAT Habitat lossLike most butterflies,
monarchs are highly
sensitive to weather and
climate. The species’
famous 3,000-mile
migration from Canada
to their winter home in
Mexico is a trip made in
search of optimal con-
ditions: They need tem-
peratures between 55 F
and the low 70s along
the route, and rain while
they hibernate; an ideal
body temperature is
also crucial for mating,
fertility, and egg-laying,
which they must do
where their caterpil-
lars’ only food source,
milkweed, is abundant.
But storms and extreme
temperatures are dis-
rupting the monarchs’
routines. Once a sum-
mertime fixture, dap-
pling backyard gardens
from coast to coast,
these crucial pollina-
tors are disappearing.
“They’re experiencing
freezes in their winter-ing habitat, and drought
and heat waves along
their route,” Advani says.
Higher temperatures
may also be driving
monarchs’ summer
breeding grounds
farther north, making
their migrations longer
and more difficult. One
study recorded a 4.9
percent increase in their
wing size over the past
century and a half — an
adaptation that likely
arose to help them make
the longer journey.
Though monarchs aren’t
endangered yet, their
numbers are dropping.
In 2018, there was a 15
percent decline in but-
terflies in Mexico com-
pared to the previous
year, and an 80 percent
decline over the previ-
ous 20 years. One set
of models predicts the
population may drop so
steeply in the next two
decades, it won’t be
able to recover.GET INVOLVED
Protect the Refuge
defenders.org
Join Defenders of Wildlife’s cam-
paign to prevent drilling in the
Alaska National Wildlife Refuge,
home to hundreds of vulnerable
species, including the largest
remaining herd of caribou.Plant Seeds of Change
worldwildlife.org
With the World Wildlife Fund,
you can apply to become
a WWF community organizer,
or join its Monarch Squad
and plant milk weed, the
butterfly’s food source.HABITAT North American mountain ranges
THREATS Compromised camouflage, habitat loss