(_Castor fiber_)
The beaver enjoys the distinction of being the only warm-blooded
quadruped that is in the habit of making really noticeable
modifications in the appearance of the earth’s surface. Many
quadrupeds, such as foxes, ant-bears, rabbits, and rats and mice
burrow holes in the ground, while the mole marks the course of its
subterranean tunnels by throwing up heaps of earth at intervals. But
although such excavations and hillocks, when sufficiently numerous,
may to a slight degree affect the appearance of a meadow, they are
nothing in comparison to the changes brought in a valley by a colony of
beavers. By throwing a dam across its course, these industrious rodents
will convert a narrow stream into a wide sheet of stagnant water, which
in the course of time may become silted up so as to form a broad and
level “beaver-meadow,” where there was originally a rocky valley. In or
near their dams beavers likewise construct dwellings of mud and clay,
known in America as “lodges,” for their own accommodation.
But this is by no means all beavers accomplish in the way of “public
works,” for, by means of the single pair of powerful chisel-like teeth
in the fore part of each jaw and the powerful muscles by which the jaws
themselves are worked, these animals, which are about the size of an
ordinary spaniel, are enabled to fell trees of considerable size, which
are used in the construction of their dams.
Beavers are the sole living representatives of a family of rodents
allied on the one hand to squirrels and dormice, and on the other to
rats and mice. Two structural peculiarities are very characteristic of
these rodents. In the first place, one of the toes of the fore-foot
is provided with a double claw, which may be used in dressing the
beautiful, long brown fur; a similar structure occurring in the smaller
rodent known as the Arctic lemming (_Dicrostonyx torquatus_). Secondly,
there is the remarkable flattened, scaly tail, which almost looks as
though it did not belong to the animal, although in reality, except
for its superior size, it is not much more abnormal than the scaly
cylindrical tail of the rat. Several myths attach to the beaver’s tail;
it was said, for instance, to be employed as a trowel for plastering
down the mud used in building the dams and lodges, although its real
use is to act as a rudder in swimming, more especially when its owner
is transporting the trunk of a felled tree. When entering the water,
or when engaged in playing therein, the beaver frequently makes a
resounding “smack” by striking the surface with its tail.
[Illustration]
In monkish times beaver-tail was considered to partake more of the
nature of fish than flesh, and was consequently allowed to be eaten on
fast days. This was, however, in the days when beavers were still
abundant in all the great rivers of Europe, from most of which they
have now been all but exterminated for the sake of their valuable fur,
and likewise for the odoriferous secretion known as castoreum, which
was formerly much used both in medicine and in perfumery. When the last
beaver was killed in the British Isles is unknown, but the species
still survived in Wales when the old chronicles were written; and we
have testimony as to its former existence in England not only in the
shape of skulls, teeth, and bones dug up from time to time in the peat
of the fens and other superficial deposits, but also in place-names
such as Beverley, in Yorkshire.
Considerable colonies of beavers still exist, by the aid of special
protection, in certain parts of Scandinavia, while a few are taken from
time to time in the Rhone, but from the Rhine, and even the Vistula,
they seem to have completely disappeared. In eastern Russia they
probably still survive locally, as they doubtless do over a large part
of Siberia, although our information on this point is very defective.
Indeed the southern range of the beaver in central Asia seems to be
still unknown, although it is certain that the species never existed in
Kashmir or the Himalaya.
Of late years it has been suggested that each of the great European
river-systems possessed a special race of beavers of its own; but the
evidence adduced in favour of this opinion is at present insufficient.
Speaking broadly, the beaver may be regarded as a circumpolar animal;
although its American representative has been separated, on account of
a comparatively small difference in the shape of the bones covering the
cavity of the nose, as a distinct species, under the name of _Castor
canadensis_. Unfortunately, the Canadian beaver has been almost as much
persecuted as its European relative, and has been exterminated from
many districts.
Beavers, it need scarcely be mentioned, are thoroughly aquatic rodents,
which feed on vegetable substances, and have their entrances to their
habitations under water. They remain active all the winter, when they
swim beneath the ice. In Europe beavers have given up constructing
lodges, and live in burrows.