Biology Reference
In-Depth Information
with a number of major misconceptions that often obscure their true nature. For example, one of the
most common folk myths is that beavers pack mud, or carry mud, with their tails. They don't. How
this notion gained such currency is anyone's guess, but it simply isn't true: although a beaver's tail has
many uses, packing mud isn't one of them. Whenever beavers need to carry or pack mud while con-
structing their dams or houses, they use their front paws.
That fact fails to diminish in the slightest the importance of the beaver's tail. Broad, flat, hairless,
and scaly, it's shaped like the blade of an old-fashioned canoe paddle. In fact the familiar and still-pop-
ular canoe paddle design is referred to as a beavertail paddle.
The tail's unique conformation makes it suitable for so many purposes that it serves its owner as
a virtual tool kit. For openers, the tail is the beaver's alarm signal. Anyone who's spent much time
around a beaver pond, especially at dusk, is familiar with the loud
ka-WHOP
that resounds across the
still waters. When a beaver detects human presence—or any other form of potential danger—it warns
the other members of its colony by slamming its tail forcefully onto the surface of the water. The result
is a mighty splash similar to what one would expect if a fifty-pound rock were heaved into the water!
Of necessity, beavers spend much of their time swimming, and the wide tail acts as both rudder and
diving plane while the beaver moves to and fro, up and down, within its watery domain. A beaver's tail
is also very fatty, and this fat can act as an emergency food supply in time of famine. And because it's
hairless, the tail functions as a heat exchange mechanism during periods when its owner is exception-
ally active. It even serves as a brace or prop while the beaver sits up and gnaws during the process of
felling trees. Clearly, the beaver's tail is the very model of a utilitarian appendage—but the one thing it
doesn't do is pack mud!
Another common myth is that beavers, like human loggers, can fell trees in the desired direction.
The truth is far less glamorous. The beaver is a rodent, with incisors that act as big, sharp chisels. When
a beaver decides to cut down a tree, it usually gnaws a V-shaped notch completely round the tree, slant-
ing up from the bottom and down from the top to meet at the apex of the cut.
The beaver continues to work around the tree, all the while deepening and enlarging the notch. Even-
tually there's too little wood left in the middle to support the tree, and it falls, willy-nilly, in any old
direction. Far from knowing or planning the direction of fall, beavers are occasionally killed when the
trees they're felling accidentally land on them. Sometimes a beaver will gnaw through a tree from only
one side, but that choice assuredly isn't dictated by any intention of felling the tree toward a particular
spot.
It's fascinating to speculate on the many ways in which misconceptions about wildlife begin. Some
are fairly easy to fathom, others less so. We like to be charitable and think that people are honest, but
some individuals make up tall tales and pass them off as the truth, or just plain lie for reasons best
known only to themselves. A case in point is the conversation I had with one man about beavers.
He assured me with a perfectly straight face that he had personally watched beavers packing mud
with their tails. Further, he said that he had seen a beaver fell a hardwood tree over a foot in diameter in
less than five minutes. Beavers can remove sizable chips with those big front teeth, but they certainly
