Refuge Notebook
Peninsula Clarion Article
Dated
18 February 2000
Winter Wildlife Survival Strategies: Endure, Hide or Flee
by Candace Ward
The Kenai Peninsula's six-month
long winters begin to wear on its human animals by February each year. Whenever
you feel tired of winter, remember you could be spending your winter like some
of the hardy wildlife residents of Kenai National Wildlife Refuge. Let's take
a closer look how they cope with winter's challenges.
The small wood
frog spends its winter frozen solid beneath several inches of soil and leaf litter.
If you uncovered a wood frog in the middle of winter, as did arctic explorer Samuel
Hearne, it would appear to be dead. He wrote in his journal in
1770, "I have
frequently seen wood frogs dug up with the moss when pitching tents in winter
frozen hard as ice. By wrapping them in warm skins and exposing them to a slow
fire they soon recover life."
Anyone who has experienced frostbite has
to wonder how wood frogs manage to completely freeze, thaw, and live. Apparently,
instead of water freezing inside their cells, ice crystals form outside the cell
membrane which prevents the cells from rupturing. Scientists are fascinated by
this amazing survival feat and are working to solve its mystery. They hope to
use the wood frog's winter survival strategy to extend the viability of organs
such as hearts, kidneys, and livers used in organ transplants.
Have you
ever wondered how a tiny bird like the common redpoll manages to survive those
minus 40 degrees F. nights? Redpolls, the smallest birds to winter in Alaska,
use snow cavities to roost at night which insulates them from outside air temperatures
by as much as 40 degrees F. Redpolls are flock birds, and they nestle down with
flock-mates to increase their warmth by as much as 30%. They also pack away a
dinner as they forage for seeds during the day; they store extra food in their
crops which they regurgitate at night to provide fuel to survive the cold darkness.
Finally, they are able to turn down their internal thermostats. Normally, they
maintain a body temperature of 104 degrees F., but on cold nights they can lower
their body temperatures to 86 degrees F. to conserve energy.
Wolverines
are known as hyenas of the North because of their powerful teeth and jaws and
excellent ability to hunt and scavenge. They have extraordinary fur that is highly
resistant to snowballing and icing. Their fur coat keeps them ice-free and well
insulated in all the vagaries of winter weather from ice rain to hoar frost.
During winters with exceptionally deep snow, wolverines have been known to
tackle and kill animals as large as caribou and moose. Usually, they let wolf
packs do the hunting for them and clean up the remains of caribou and moose kills
by consuming the leftovers including bones and hides. Some wolverines have been
known to survive winter months solely by eating animal bones. Since bones contain
40% protein, bones are quite nutritious if you can break them up into small enough
pieces to swallow and digest. Wolverines are well equipped to this task and crush
bones with their powerful teeth and jaws.
Generally, wild animals cope
with winter in three ways: they endure it like the wolverine, moose, and caribou;
they hide from it like brown bear, wood frog, and marmot; or they flee from it
like migratory birds such as common loons, robins, and swallows. During winter
many of us are lucky enough to use the migratory bird strategy to escape to warmer
climates like Hawaii and Mexico. We may even encounter our summer birds friends
such as golden plovers in Hawaii or common loons in Baja California in our southern
travels. Fortunately, spring is only two months away and those same birds will
head our way to find mates and food in the Land of the Midnight Sun. Winter will
become a distant memory to all of us as we revel in the long daylight and warmer
temperatures of spring and summer.
An excellent resource book on how
wildlife survive winter, which I used as reference material for this article,
is "A is for Arctic: Natural Wonders of the Polar World" by Wayne Lynch. This
book is available at the bookstore at Refuge Headquarters on Ski Hill Road.
--------------
Candace Ward has worked as park ranger at Kenai National
Wildlife Refuge for 15 years specializing in refuge information and education
programs. For more information on Kenai National Wildlife Refuge, including past
Refuge Notebook columns, check out our website at www.r7.fws.gov.
Last updated: June 16, 2008
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