DO ANIMALS TURN WHITE IN THE ARCTIC BUT NOT THE ANTARCTIC?
January 6, 2013
Why do so many animals turn white in winter or stay white all year at
the North Pole but not at the South Pole? Wouldnt the same camouflage
conditions apply to both? Will global warming
affect these color patterns?
Throughout the animal kingdom, in circumstances where being unseen or
at least inconspicuous is beneficial, camouflage is critical for prey
and predators alike.
both polar regions have plenty of snow to make a white body effective
camouflage under certain conditions. However, the Arctic includes vast
areas of terrestrial habitats, such as Alaska, Canada, and Russia, whereas
Antarctica has no physical connection to another continent.
during the summer (even without the effects of climate change), 90 percent
of the Arctic is not frozen, whereas more than 90 percent of Antarctica
is permanently covered with ice and snow. The ecological consequence
is that the Arctic has a variety of strictly terrestrial mammals and
Antarctica has none.
the strategies of native inhabitants in the two regions vary greatly,
which means some animals at the North Pole must change their appearance
seasonally to be camouflaged.
which are found at the South Pole but not the North Pole, are primarily
black and white. Being solid white would serve little advantage to an
animal that has no land predators to hide from and has to dive for fish
on dark waters. Most penguins have a dark back and lighter colored front.
helps these flightless birds be inconspicuous when observed from above
or below while swimming. Likewise, there are no terrestrial predators
that need to be white so they can sneak up on unsuspecting prey.
for avoiding predators and catching prey are entirely different in the
is defined as regions of tundra and permanent ice cover above the tree
line in North America, Europe, and Asia. Being seen would be a disadvantage
for prey animals like Arctic hares (found from northeastern Canada to
Greenland) or snowshoe hares (found from Alaska through southern Canada
and the northern United States).
best in a brown coat during warm months when the soil surface is visible.
In the cold Arctic portion of their geographic ranges, when autumn snow
begins to whiten the surroundings, white is the best color for a coat.
Seasonal color change from brown to white also occurs in some non-Arctic
whitetail jackrabbits do not occur in the Arctic, but they are found
in northern portions of the western United States and into southern
Canada. In the coldest and snowiest parts of their geographic range,
they turn white in winter.
fox adopts a similar seasonal color change tactic for two reasons.
Arctic foxes do not want to be seen by rodents and hares, which are
the prey of these wily predators.
Arctic foxes often scavenge in winter, dining on the remains of seal
or fish left by polar bears. Presumably, polar bears would eat a fox
as well, so having a wintertime camouflage of pure white (or sometimes
bluish-gray) fur works well for the fox. In summer, brown becomes the
fashion, as with the hares and many other Arctic mammals.
coats of Arctic animals have long been popular in the fashion industry,
and a magnificent white ermine coat was once the most elegant of winter
ermine, with only a black tail tip, must be caught during the Arctic
winter. In the summer the ermine turns mahogany brown. One interpretation
of scientific predictions about climate change in polar regions is that
white might not continue to be a necessary part of the wardrobe of Arctic
animals. But how they will adjust to this change is unknown.
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