Leave
it to beaver
Wild Williamsburg chews on a new year
By Callan Bentley
Flat Hat Staff Writer
Welcome to a new year in Wild Williamsburg. For those not yet acquainted with the ins and outs of The Flat Hat, this is a weekly column which discusses many aspects of the natural world pertaining to this area.
I was in New Hampshire several
years ago for an aunt's wedding, and while the relatives were socializing one
day, my brother and I took a short hike. We came to a classic New England pond,
reminiscent of Thoreau's Walden. The silvery water reflected the small trees
by the water's edge, and all seemed at peace. We were jolted by a sudden loud
sound, like a baseball being smacked out of the stadium with a bat. My brother
and I looked around, searching for a hunter's smoking gun or a pickup truck
that had backfired, but all we could see was a set of ripples spreading out
from the center of the pond. A beaver's head soon popped up amongst the ripples,
and the mystery noise was explained. Another beaver joined the first, and they
smacked their tails several more times before disappearing under the pond.
The beaver is the largest
rodent in North America. As far as the entire New World is concerned, only the
South American capybara is larger. The beaver is classified in a family of its
own (Family Castoridae) and is found exclusively in North America. There are
several other large aquatic rodents that resemble the beaver, such as the muskrat
and the nutria, but it may be readily identified both by its large size and
the broad, flattened tail that it carries.
Beavers are descended from
a group of prehistoric mammals called Castoroides, which lived on this continent
a million years ago. These animals were gigantic, weighing between 700 and 800
pounds each. Modern beavers weigh only a fraction of that amount, averaging
from 40 to 60 pounds. The world's largest beaver, caught in 1938, weighed a
whopping 115 pounds.
The beaver falls under the "rodent" classification because of the arrangement of its four incisors, with two on the top of its mouth and two on the lower jaw. It has gained much fame and infamy through the use of these efficient teeth. The beaver must constantly chew on things (such as trees or fenceposts) because its teeth are constantly growing, and in must wear them down to keep them in serviceable condition. If the beaver (or any other rodent) neglects this task, it will suffer from a condition known as malocclusion. In this condition the incisors continue to grow in an arc. Unchecked, they will curve back and pierce the animal's skull.
The beaver's fur has made
it a wanted character throughout its nationwide range. Because of the beaver's
semi-aquatic lifestyle, it has evolved fur well-adapted to insulate. Further,
the beaver has two glands located in its cloaca. These glands secrete an oil
that waterproofs the beaver's hairs to such an extent that when the animal dives
beneath the water, its skin doesn't get wet at all.
Just anterior to the oil
glands are the two castor glands, which secrete a thick yellow oil that the
beaver uses for communication with other beavers. It is from these glands that
the beaver derives its scientific name, Castor canadensis.
The beaver's fur has a great
range of color. It appears darker in the northern part of its range, and is
almost blond in the south. A commercial beaver pelt company has bred beavers
with white, black, golden, and even blue fur.
Beneath the beaver's skin
is a very tough layer of tissue and a layer of fat. The presence of these two
layers makes the beaver one of the most difficult animals to skin.
Other adaptations for the beaver's aquatic life include a nictitating membrane,
which covers the beaver's eyes. When the animal dives, this membrane protects
it during the swim underwater. Furthermore, when submerged, the ears automatically
close via a set of valves. Beavers' lungs are more adept at exchanging oxygen
than humans. The beaver can stay underwater for up to 15 minutes at a clip,
and can swim half a mile without coming up for breath.
With the single exception
of humans, no other mammal has the ability to alter its environment like the
beaver. They are well known for their propensity for dam-building. The ponds
that are subsequently created harbor many different animals and plants. It is
quite an architectural accomplishment that beavers can construct dams using
only two ingredients: mud and tree limbs.
Of course, some people resent
it when their favorite stream is transformed overnight into a limp trickle,
and beavers are detested in some parts of the country. Until last year, no solution
was available to this problem except removing or killing the beaver. A reliable
method of beaver extraction involves the use of dynamite. Thankfully, a laboratory
announced last year that a kinder, gentler alternative has been discovered:
simply spray the local trees liberally with coyote urine. The beavers will then
leave of their own accord.
The only problem with this
bold new plan is that most coyotes aren't especially generous with their urine
samples. Too bad for eco-conscious farmers and wary beavers.
There have been reports of
beavers swimming around Lake Matoaka, but these rumors are unconfirmed. Those
who think they have spotted a beaver should check for the flattened tail. If
it is a beaver, sit back and watch this animal go about its daily routine. Punctuated
by gunshot-like tail slaps and fraught with the dangers of malocclusion and
coyote pee, it ought to make for an interesting performance. Enjoy the show.