still hide themselves in the banks of the
remotest brooks of certain Russian rivers; but the
European beavers live solitarily in burrows,
rarely making dams or building lodges.

There is no mistaking the chisel teeth of the
beaver. He has two incisors and eight molars
in each jaw; and empty hollows where the
canine teeth might be. The upper pair of cutting
teeth extend far into the jaw, with a curve of
rather more than a semicircle; and the lower
pair of incisors form rather less than a semicircle.
Sometimes, one of these teeth gets broken,
and then the opposite tooth continues growing
until it forms a nearly complete circle. The
chewing muscle of the beaver is strengthened
by tendons in such a way as to give it great
power. But more is needed to enable the beavers
to eat wood. The insalivation of the dry food
is provided for by the extraordinary size of the
salivary glands.

Now, every part of these instruments is of
vital importance to the beavers. The loss
of an incisor involves the formation of an
obstructive circular tooth; deficiency of saliva
would render the food indigestible; and when
old age comes and the enamel is worn down
faster than it is renewed, the beaver is no
longer able to cut branches for its support.
Old, feeble, and poor, unable to borrow, and
ashamed to beg, he steals cuttings, and subjects
himself to the penalty assigned to theft. Aged
beavers are often found dead with gashes in
their bodies, showing that they have been
killed by their mates. In the fall of 1864
a very aged beaver was caught in one of
the dams of the Esconauba river, and this was
the reflection of a great authority on the
occasion, one Ah-she-gos, an Ojibwa trapper:
"had he escaped the trap he would have been
killed before the winter was over, by other
beavers, for stealing cuttings."

When the beavers are about two or three
years old, their teeth are in their best condition
for cutting. On the Upper Missouri they cut
the cotton tree and the willow bush; around
Hudson's Bay and Lake Superior in addition
to the willow they cut the poplar and maple,
hemlock, spruce, and pine. The cutting is round
and round, and deepest upon the side on which
they wish the tree to fall. Indians and trappers
have seen beavers cutting trees. The felling
of a tree is a family affair. No more than a
single pair with two or three young ones are
engaged at a time. The adults take the cutting
in turns, one gnawing and the other watching;
and occasionally a youngster trying his
incisors. The beaver whilst gnawing sits on his
plantigrade hind legs, which keep him conveniently
upright. When the tree begins to
crackle the beavers work cautiously, and when
it crashes down they plunge into the pond,
fearful least the noise should attract an enemy
to the spot. After the tree-fall, comes the
lopping of the branches. A single tree may be
winter provision for a family. Branches five
or six inches thick have to be cut into proper
lengths for transport, and are then taken and
sunk in a pile near the family lodge. As
many as nine beavers have been counted at this
work; but half the number would be nearer
the average engaged. Night after night the
beavers are busy in September and October,
until the first snows fall on the swamps, and
the first frosts film the ponds. Trees are often
felled in ponds, that their branches may be
preserved within reach under the ice. A cutting
of a wild cherry tree eighteen inches in
diameter, and with rings cut at three different
heights, is to be seen in the state collection at
Albany. The different heights of the rings
seem to show that the cutting was begun at
separate times, when the snow was sinking:
for the beavers take immediate advantage of
the earliest thaws to replenish with fresh twigs
their sour stores. Beaver chips are curiosities.
They seem to prove that the upper incisors
hold, and the lower gnaw and split, the wood.
Judging from the chips, a tree a foot in diameter
and three feet in circumference must require
three nights' work. Cottonwood trees are soft,
but sometimes two feet across, and one of three
feet was once found cut through. Sticks are
first cut on one side into convenient lengths,
and when all the gnawings are done on one
side the stick is turned.

M. Sarrasin reported to the Academy of
Sciences that beavers not only eat bark and
twigs, but also wood. This statement has
fallen into discredit; but Dr. W. W. Ely
dissected three beavers for Mr. Morgan, and found
little else in their stomachs except lignite,
unmistakable particles of comminuted wood. When
in February and March the sap starts upward
the beavers eat the wood for the sake of the
saccharine juices. Evergreen trees, the bark
of which is never eaten by beavers, are cut
down by them; and this is done, it is supposed,
for the sake of the sweet gums they exude, and
the nutritious mosses growing on them.

Constructed for the land and the water,
the beavers live half-land and half-water
lives. In all diving animals provision is
made against asphyxia; the diving spider
takes his bubble of air with him; diving birds
and mammals have cavities in which blood may
be stopped and kept during the dive. Unvitalised
blood is kept in these cavities; and out of the
brain and the arteries where its presence would
be fatal. Men would not be so easily drowned
and hanged as they are, if they had such holes
for holding their black venous blood. Trappers
say that a beaver can remain under water for
ten minutes, and swim in the time a quarter of
a mile. Beavers and musk rats, it is said, can
travel far under ice, by coming up at intervals
to the surface of the water, just under the ice,
emitting their carbonic acid gas, and inhaling
fresh breaths of respirable air.

Beavers migrate. In May and June, every
year, the beavers come down the Missouri;
once down, the current prevents their getting
up again. The Indians say the old beavers
go up and the young ones down rivers; the
old being wise enough to take the route to