Biology Reference
In-Depth Information
certainly not afraid of humans and may approach out of curiosity, with no aggressive intent; some have
likely never laid eyes on one of our species before, which might also be a cause of their curiosity. Some
polar bears, however, are highly aggressive, so all of them should be regarded as armed and dangerous.
As proof of this, an Inuit campsite on the western shore of Hudson Bay was recently attacked by a polar
bear. A woman was killed, and a man and boy were seriously injured.
Like the brown bear, the polar bear breeds only every third year. It usually has two cubs, though oc-
casionally only one. The female dens before giving birth, although the word
den
can be something of
a misnomer in the polar bear's case. Often the female will dig a den in a snow bank or a peat bed, but
sometimes she'll simply curl up in the snow and allow falling and drifting snow to cover her deeply
enough so that a small but snug cavity is formed. Remarkably, males, as well as females with cubs,
don't den, but remain active through the incredibly bitter arctic winter!
Because polar bears, unlike their black and brown cousins, are completely exposed to view, attacks
by male polar bears on cubs, as well as the mothers' defense of them, are well documented. According
to Gary Alt, their method of attack is vastly different from that of brown and black bears. In the case
of the latter two, the attack is a savage rush that is quickly over. Either the female successfully defends
her cubs against the oncoming male, or he kills one or more of them. With polar bears, since the female
and cubs are visible at all times and have no place to hide, the process is a long, slow stalk covering
mile after mile.
While the male stalks behind, the female keeps a watchful eye on him as the cubs hold tight to her
flanks. Every so often, when she loses patience, the female turns and charges the male. Amazingly, the
cubs charge with her in a move that Alt says is so beautifully choreographed that it's as if only one body
were moving, instead of three!
Only rarely does a cub separate from its mother, in which case it's usually seized and killed by the
male. More commonly, however, the female, with cubs glued to her sides, charges the male every little
while, persevering until the male at last gives up and goes away.
On the whole, our three North American bears seem to be thriving. No longer viewed as nuisance
animals, or worse, to be eradicated as quickly as possible, they're now being seen for what they
are—fascinating, immensely powerful predators that have a place in the scheme of things. True, grizz-
lies in the American West still have many detractors and are controversial, but a rapidly growing num-
ber of supporters seek to retain them or reintroduce them where possible. As large, free-roaming pred-
ators, all three species depend on major blocks of suitable habitat as the key to permanent survival. As
long as we protect and maintain such habitat, these magnificent animals will continue to be a part of
our world.
