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Learn more about
POLAR BEARS... the icons of the Arctic.
2008 has been designated the Year of
the Polar Bear
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AZA: Association of Zoos and
Aquariums - The Louisville Zoo is a member of the American
Zoo and Aquarium Association (AZA), an organization that
represents and accredits professionally managed zoos and
aquariums in North America. For more information on AZA,
visit
www.aza.org.
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Churchill, Manitoba: Located on
the shores of Hudson Bay, the Town of Churchill has a rich
past. Once a military base for United States and Canada it
is now a small town of about 1,000. It was given the name
“Polar Bear Capital of the World,” because of its vast
population of polar bears. The economy is based on a number
of thriving sectors such as mining, transportation,
forestry, commercial fishing, trapping and tourism.
Ecosystem:
A system formed by the interaction of a community of
organisms with their environment.
Walking
Hibernation: Polar bears that spend the late summer and
fall on the shores of Hudson Bay, beyond the reach of seals,
enter a state of hibernation due to the lack of food.
Because they don’t den, scientists have dubbed the condition
“walking hibernation.”
Hibernation in the true sense of the word does not apply to
polar bears. True hibernators experience a marked drop in
heart rate and a body temperature that plunges to nearly 32
degree F. It may take some time to wake them up.
Denning bears,
including brown and black bears, are not true hibernators.
Though their heart rate slows, their body temperature fails
to undergo a dramatic decline, usually dropping to about 88
to 93 degrees F. They may sleep deeply, but have no
difficulty waking up.
Bears do not enter a state of deep hibernation because they
need a higher body temperature in order to meet the demands
of pregnancy, birth and the nursing of young. Though brown
and black bears hibernate in winter, all polar bears do not.
Only pregnant females hole up in a den. The rest of the
population remains active throughout the year. Pregnant
female polar bears den up in the fall after feeding heavily
in August and September. Most choose den sites in snowdrifts
along mountain slopes or hills near the sea ice. Others den
in banks of snow on the frozen sea. To build her den, the
female scrapes a tunnel into the snow and digs two chambers.
She gives birth to her cubs in November or December. When a
female polar bear emerges from her den in March or April,
she is in a physiological state similar to that of a
hibernating black bear. Her body temperature, however, does
not drop quite as low as that of a black bear. Instead it
ranges from 95 to 98.6 degrees F.
Interestingly,
polar bears appear to have the ability to control their
hibernation. A study done on a group of Hudson Bay polar
bears that fed at a garbage dump during the fall “lean
period” revealed that the animals were not in a state of
hibernation. Those bears, however, that steered clear of the
dump were.
Scientist Ian
Stirling points out that a black bear deprived of food in
summer would starve. A polar bear, however, appears to have
the ability to turn on its hibernation mode when food is
scarce and to turn it off when food becomes more abundant
again.
Sources: PBI (www.polarbearsinternational.org/bear-facts/hibernation-facts/)
- Polar Bear by Downs Matthews (Chronicle Books, 1993);
Polar Bears by Ian Stirling (University of Michigan Press,
1988).
What is the polar bear’s scientific
name?
Ursus maritimus or the
“sea bear.” Its closest relative is the brown bear
How many polar bears do you have?
One. His name is Aquila. He was actually
born at the Louisville Zoo 13 years ago. Then, after a stay
at the North Carolina Zoo, he returned to his home in
Louisville eight years ago.
Once the Zoo opens Glacier Run in 2010, we
hope to house up to six adult polar bears. Glacier Run will
also include seals, sea lions, Stellar sea eagles, artic
fox, sea otters and more.
How many polar bears are in zoos around
the world?
There are 246 polar bears in captivity,
and currently about 27,000 polar bears in the world. Polar
bears can be found in the wild in Alaska,
Canada, Russia, Denmark (Greenland), and Norway. To
see a list of zoos with polar bears, visit
http://www.polarbearsinternational.org/zoos-with-polar-bears/.
What do polar bears eat?
Seals are the polar bear’s
primary prey, particularly the ringed seal and, sometimes,
the bearded seal. When hunting is good, polar bears will
typically eat only the fat and leave the rest of the carcass
for scavengers. At the Louisville Zoo, Aquila eats things
like capelins (small silver-colored fish), apples and
bones.
Do polar bears really have white fur?
No, polar bear’s fur is
not white. Actually, their skin is black and each hair shaft
is pigment-free and transparent with a hollow core. Polar
bears look white because the hollow core scatters and
reflects visible light, much like ice and snow does.
How big do polar bears
get and what is their life span?
Adult male polar bears are
8 to 10 feet tall. They weigh 550 to 1,700 pounds. Adult
female bears are 6 to 8 feet tall and weight 200 to 700
pounds. On average, polar bears in the wild live 15 to 18
years. However, some have lived up to their early 30s. In
captivity, they may live up to their mid-to late 30s.
Do polar bears
hibernate?
No, polar bears do not
hibernate. For a polar bear to hibernate, it would have to
have a marked drop in heart rate and a body temperature that
drops to 32 degrees F. Polar bears do not go through this
stage. Instead they undergo a “walking hibernation.”
“Walking
hibernation” is a term scientists have dubbed for polar
bears that enter a state of hibernation due to lake of food
but don’t den.
Hibernation in
the true sense of the word does not apply to polar bears.
True hibernators experience a marked drop in heart rate and
a body temperature that plunges to nearly 32 degree F. It
may take some time to wake them up.
Denning bears,
including brown and black bears, are not true hibernators.
Though their heart rate slows, their body temperature fails
to undergo a dramatic decline, usually dropping to about 88
to 93 degrees F. They may sleep deeply, but have no
difficulty waking up.
Bears do not enter a state of deep hibernation because they
need a higher body temperature in order to meet the demands
of pregnancy, birth and the nursing of young. Though brown
and black bears hibernate in winter, all polar bears do not.
Only pregnant females hole up in a den. The rest of the
population remains active throughout the year. Pregnant
female polar bears den up in the fall after feeding heavily
in August and September. Most choose den sites in snowdrifts
along mountain slopes or hills near the sea ice. Others den
in banks of snow on the frozen sea. To build her den, the
female scrapes a tunnel into the snow and digs two chambers.
She gives birth to her cubs in November or December. When a
female polar bear emerges from her den in March or April,
she is in a physiological state similar to that of a
hibernating black bear. Her body temperature, however, does
not drop quite as low as that of a black bear. Instead it
ranges from 95 to 98.6 degrees F.
Interestingly,
polar bears appear to have the ability to control their
hibernation. A study done on a group of Hudson Bay polar
bears that fed at a garbage dump during the fall “lean
period” revealed that the animals were not in a state of
hibernation. Those bears, however, that steered clear of the
dump were.
Scientist Ian
Stirling points out that a black bear deprived of food in
summer would starve. A polar bear, however, appears to have
the ability to turn on its hibernation mode when food is
scarce and to turn it off when food becomes more abundant
again.
Sources: PBI (www.polarbearsinternational.org/bear-facts/hibernation-facts/)
- Polar Bear by Downs Matthews (Chronicle Books, 1993);
Polar Bears by Ian Stirling (University of Michigan Press,
1988).
How do polar bears keep
from freezing?
Polar bears are well
adapted to the cold frigid weather of the Artic, where it
can be as cold as -50 degrees. Two layers of fur and a layer
of blubber (that can measure 4.5 inches thick) create
excellent insulation. Also, the bears have compact ears and
tails that prevent heat loss. Their feet have small bumps
called papillae that keep them from slipping on the ice, and
powerful claws that dig into the ice and catch prey.
Why are polar bear populations declining
and why is it important to save them?
Polar bears are facing many issues. The
major threat is climate change. Scientists have stated that
the ice packs are starting their seasonal melt an average of
two weeks earlier than usual. When ice starts to melt the
seals go back into the open water. This creates a situation
in which polar bears have to gain enough fat in a shorter
time period to last them through harsh seasons ahead. It is
crucial that the polar bears eat enough from April to summer
to last through the long summer and fall fast. It is
especially important that female polar bears do not become
too lean as this would stop them from producing milk and
cause their cubs to die.
Another problem polar bears are facing is
melting sea ice that is retreating away from the main lands.
Polar bears are known for being excellent swimmers that can
swim up to 60 miles. However, with melting sea ice, the ice
has moved up north 160 miles from the Alaskan coast. Many
polar bears have drowned due to exhaustion in trying to find
the solid ice. If the future of the
environment does not change than it is likely they will
become endangered.
The Western
Hudson Bay population, the most studied group of bears,
dropped from 1,140 to 950 in the past decade. The average
weight of females is down from 583 pounds to 418 pounds,
which has negative reproductive consequences. Moreover, the
mortality rate for bears between birth and age 5 is up 50
percent because of the shortened hunting time on the ice,
said Robert Buchanan, president of Polar Bears International
(PBI), a group that supports research and education.
“There’s a
difference between weather and climate, but I’ve never
experienced it this warm for this long in all the years I’ve
been coming here,” said Buchanan, a 20-year bear-season
resident of Churchill. “Is it disturbing? Yes. Polar bears
are the sentinel species for global climate change. They’re
the canary in the coal mine.”
As Buchanan
notes, polar bears are important because they are considered
an “indicator species” and compared to canaries in a coal
mine.
Early coal
miners didn’t have the special equipment miners have today
to measure methane gas in the air, so it was impossible to
tell if the gases were building up to dangerous levels.
Miners started to use canaries to test the air quality in
the mines. Canaries are very sensitive to carbon monoxide.
The canaries would chirp and sing and make noise all day
long. But, if the carbon monoxide levels got too high, the
canaries would have
trouble breathing, and maybe even die. When the canaries
were no longer singing, miners would know that the gas
levels were too high. They would leave the mine quickly to
avoid being caught in an explosion. This is how canaries
acted as a warning system for miners. (http://www.petcaretips.net/canary-coal-mine.html)
In the same
way, polar bears are a warning system for climate change.
With the decline in the polar bears’ habitat, along with
other ice-inhabiting marine mammals in the Arctic, it is an
indication that climate change is truly affecting the living
organisms that exist within that ecosystem.
Canada’s Western Hudson
Bay polar bear population has dropped 22 percent since the
early 1980s, and two-thirds of the world’s polar bear
population could disappear by 2050 (National Geographic -
http://news.nationalgeographic.com/news/2007/09/070910-polar-bears.html).
Other threats to polar
bears include pollution, poaching and industrial
disturbances.
The U.S. Fish and Wildlife Service has
proposed that polar bears be added to the Threatened Species
list under the U.S. Endangered Species Act. Canada and
Russia both list the polar bear as “a species of concern.”
In 2005, the world’s leading polar bear scientists
reclassified the polar bear as vulnerable on the IUCN World
Conservation Union’s “Red List of Threatened Species,”
noting that the species could become extinct due to sea ice
changes. To read the entire 198-page IUCN report, visit
http://www.polarbearsinternational.org/rsrc/Proc_Seattle05.pdf.
What is “Year of the Polar Bear”?
Polar Bear
International has partnered with zoos throughout the world
to make 2008 the Year of the Polar Bear.
For more information click
HERE.
What polar bear conservation efforts are
the Louisville Zoo involved in?
Louisville Zoo partners with Polar Bears
International (PBI)—a non-profit organization that promotes
conservation through research and education. For more
information on PBI, visit
http://www.polarbearsinternational.org/.
How can I help protect and save polar
bears?
One great way to help our planet,
including protecting polar bears, is by being an informed
consumer. Think carefully about how the things you do and
the things you buy affect the environment. For more tips,
check out this list compiled by Emily Goldstein, the
Louisville Zoo’s teen artic ambassador click
HERE
Another way you can help is by donating to
the Louisville Zoo’s Glacier Run Exhibit. To do this, visit
www.louisvillezoo.org/glacierrun or call Louisville Zoo
Development Director Jill Gorsky at (502) 238-5614 for more
information or to make a donation.
Also, did you know that when you visit the
Louisville Zoo admission fees and other purchases help us to
preserve and care for species that are threatened and
endangered as well as support critical conservation
education programs? In addition, 15 cents of every
admission and $1 of every zoo membership supports our
partnerships in conservation projects worldwide.
How can I find out more information on
polar bears?
Check out these links:
The Zoo is currently working on a $25
million capital campaign for the upcoming Glacier Run
Exhibit, which is expected to be completed in 2010. For more
information:
This year
Louisville Zoo selected Emily Goldstein as the Zoo’s teen
ambassador for the Polar Bear International (PBI) week-long
Polar Bear Leadership Camp. She joined 15 other high school
students from around the world to study polar bears during
their fall migration and collect field data with
scientists. The camp included intense field work and
allowed students to see all sides of the issues polar bears
and humans in the Churchill region are facing.
For more
information about Emily and her trip, check out:
This is a polar bear that Emily Goldstein saw up-close-and-personal during her recent trip to Churchill, Manitoba, Canada. This was the polar bear that Emily says “stole her heart,” and made an indelible impression on her. Emily captured this polar bear resting in Churchill, Manitoba, Canada. Emily said her trip to Churchill, Manitoba, Canada, was a trip of a lifetime. Here, she a polar bear is pictured behind her. This is a sign Emily said dotted the landscape of Churchill, Manitoba, Canada. Aquila, the Louisville Zoo’s current polar bear, enjoys a pumpkin while floating in his exhibit. Aquila, the Louisville Zoo’s current polar bear, enjoys a special “polar popsicle” made by Zoo staff. Aquila, the Louisville Zoo’s current polar bear.
This is a polar bear that Emily Goldstein saw up-close-and-personal during her recent trip to Churchill, Manitoba, Canada.
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