BEARS CAN BE A SUMMER TREAT
July 1, 2012
longest day of the year having passed, we can begin looking forward
to cooler weather. Well, not really for awhile, unless you happen to
be roaming around on the Arctic ice cap with polar bears. And you can
do just that in a virtual sense with an outstanding nature book. "Polar
Bears: A Complete Guide to Their Biology and Behavior" (2012, Johns
Hopkins University Press, $39.95) by Andrew E. Derocher is a scientifically
accurate, superbly edited account of the king of the Arctic. The spellbinding
photography of Wayne Lynch, which accompanies the text, makes "Polar
Bears" hard to put down.
is full of facts about this most recognizable of the world's bears.
The caption of the first magnificent photo of a startlingly white bear
walking on sea ice notes that they are the only bear of the eight species
that has a predominately carnivorous diet. Their main prey is several
species of seals, a diet that is energy rich because of the fat content
of seal blubber. But polar bears apparently will go after almost any
animal, including small whales, sea birds, and reindeer. Because of
the uncertainty of finding prey from day to day, polar bears take full
advantage of every capture, eating as much as 20 percent of their body
weight in a single meal.
mammals and birds spend time out of water, resting on ice floes or land.
Of these, only adult male walruses are mostly immune from bear attacks.
Not surprising for an animal that can weigh almost two tons and has
formidable weapons--walrus tusks can be three feet long! Any other animal
on the polar ice needs to stay alert and have an escape route when a
bear approaches. One inexplicable finding is that polar bears have occasionally
been observed eating blueberries and seaweed, which seem to have little
Arctic predators normally give birth to twins, which the mother nurses
through winter in a snow-covered den without food for herself. When
spring arrives she must replenish her body with prey she captures while
teaching her babies to hunt for themselves. One hazard for polar bear
cubs is getting wet when they are very young. Just like humans, they
can die from hypothermia, so mothers carefully select their walkways
over the ice so cubs do not have to swim.
of polar bears is somewhat remarkable considering the Arctic conditions
that any human would define as harsh and unforgiving. Nonetheless, the
author notes that polar bears often live more than a quarter of a century.
Records in the wild are 32 years for a female and 28 for a male. In
captivity they have been known to live several years longer than that.
The book's information that males have shorter life spans than females
is a testament to the extensive scientific research conducted by the
author and to his knowledge of bear biology. Male polar bears have significantly
larger heads and bigger teeth, and weigh twice as much as females, common
characteristics among species in which adult males engage in combat.
Injuries and deaths of many male polar bears are a consequence of fighting
with a larger opponent, especially if that opponent is younger and healthier.
chapter titled "Threats," the author notes that polar bears
continue to be hunted, both legally and illegally. Other factors can
also cause population declines, including pollution from pesticides,
oil spills, and industrial compounds. But "global warming is the
greatest threat facing polar bears because it does not merely threaten
individual bears. It threatens the entire species."
Polar bears are awesome creatures living in an otherworldly habitat.
The fine writing and 175 stunning color photographs bring the Arctic
scene and its inhabitants to life like no book before. When looking
for a gift for someone in hot weather or cold, you are not allowed to
give them a polar bear. But this beautiful, readable, and affordable
book should be well received by anyone.
you have an environmental question or comment, email