, and alternately keep guard; this is a
well-known practice of many animals both in work and play. As soon as
the tree begins to bend and crack, they cease cutting and make sure of
their definite direction of escape, then they continue to gnaw until it
begins to fall, whereupon they plunge into the stream, usually, where
they remain for some time lest the noise of the falling tree attract the
attention of enemies.

Their next work is to cut up the tree into sections which they can
remove. If the tree is not too large and has already fallen in the
water, they take it as it is, otherwise it must be cut up and conveyed
to the dam. No professional lumberman better understands how to
transport lumber to a desired place than beavers. They realise the value
of water transportation and thoroughly appreciate that trees can only be
removed downhill. From tame beavers we have learned that they remove
smaller limbs by seizing them with their teeth, throwing the loose end
over their shoulder, and then dragging them to their destination.

These water-loving animals rely mainly upon their native element for the
movement of lumber and food, and to aid this they employ engineering
skill that is rivalled only by their feats of tree-cutting and
dam-building. This constructive faculty is shown largely in their
canal-digging. From one small stream to another, or from one lake to
another, they excavate canals from three to four feet in width, with a
water depth of two feet, and occasionally one hundred and fifty to two
hundred feet in length. The amount of labour they perform is almost
unbelievable; every particle of dirt is carried away between their chin
and fore-paws. This earth is sometimes used in plastering up a nearby
dam or repairing their winter home. Small and tender twigs are
transported to the vicinity of their lodges, and then sunk for winter
food.

Mr. Morgan has made a close study of these canals, and in speaking of
them he says that when he first saw them, and heard them called canals,
he doubted their artificial origin; but upon examination he found that
they were unquestionably beaver excavations. He considers these
artificial canals, by means of which the beavers carry their wood to
their lodges, the supreme act of intelligence on the part of these wise
animals. Even the dam, remarkable as it is, does not show evidence of
greater skill than that displayed in the making of these canals. No one
who has ever understood the