New-York tribune., 1868-03-27
NEW PUBLICATIONS.
THE AMERICAN BEAvER.


On the south shore of Lake Superior the author of
this volume obtained opportunity for studying
The habits and works of the American beaver. The
line of the railroad passed through the most remark
able beaver district in the country. AS the wilder
ness was opened in advance of actual settlement
the beaver was surprised in the midst of his works
For several successive summers, the business OF the
author led him to that region, and taking up Ihe
study of the habits of the beaver n reereailOh IL
was not long before he had accumulated mass oi
knowledge on the subject which for eA'en' ulu "0
curacy, finds no parallel in TIE previous
Of scientific naturasts His o9seI alions
additional value from series of photograI.N *
which are here for the first time applied to the illus
tEation of the architecture OF the beaver WIN
sueh materials at his command, Mr. Morgan has COM
pieted monograph which must be regarded as the
hest contribution hitherto made to the knowledge OF
that remarkable animal. brief summary OF the
sesults of his labors cannot fail to interest our
readers.
The American beaver when full grown, attains the
weight of from thirty to sixty pounds. In folln lie
s short between the fore and hind legs broad heaVy
and clumsy He walks with waddling gait, and ms
motions are slow and awkward. An ordinary dog
could overtake him in short chase. In the wafer
which is his natural element his motions are COM
paratively free and graceful He propels himself IN
swimming by the hind legs. The fore feet are not
used being too small for that purpose and are pressed
back against the abdomen. The paws are capable OF
considerable rotary movement enabling him to hold
sticks and limbs of trees, and to handle them win
great dexterity while cutting them.
The normal habitation of the beaver is the bur
now rather than the lodge. lie excavates long
ohambers under ground, with his long and curv-
iag claws In its FORM structure. and uses, the tail
Is his most conspicuous organ. 1t IS nearly nat
broad and straight aud every portion of its surface
is covered with horny plates of ustrous black, with
The appearance of scales. Its principal uses are to
elevate or depress the head while swimming to turn
the body and vary its direction and 10 assist the AMI
NAL in diving 1t is also used to give signal OF
alarm TO its mates. When alarmed in his pond, he
Immediately dives and he descends head foremost,
the tail which is thrown out of water is brought
down upon the surface with heavy stroke, throwing
ND the spray two OF three feet high and making
report like pistol shot. 1t has often been asserted
that the beaver his tail as trowel IN preparing
Bortar from mud. But this is g mistake. He uses
Saud and soft earth sometimes intermixed withroots
and grass, precisely as he finds them, without any
preparatOn whatever. Buthe employs his tah TO pack
aud compress mud and earth while constructing
lodge or dam, which he effects by repeated heavy
down strokes, an operation not unlike some OF the
uses of the trOwel.
fhe optic nerve is a mere thread and his vision of
abort range. His hearing, the contrary, Is very
acute and he relies on this sense TO much greater
extent than on the sight He sits up his hind legs
80 lAlen which is his usual position when suspicious
Of danger, and after listening for some time will
retire and return at intervals to repeat the obserya-
tiOn.
The social propensities furnish another striking
characteristic of these animals. it is their habit to
&, L. olaNfov
until the latter obtain maturity when they are forced
70 leave the parent lodge Two more such families
usually inhabit the same pond and contribute their
labor to the maintenance of the dam but the com
mon opinion that they live in colonies is an error.
Bach family has its own lodge and burrOw, and its
separate stock of winter provisions There is no
evidence of any concert of action among several fain
hes and if such cases have occurred, they form an
exception to the general rule.
Within the district explored by Mr.. Morgan, com
prisng an area of eight miles by six. there sixty
three beaver dams from those which fifty feet in
length, and forming ponds covering quarter of an
acre of land, to those which three hundred and
five hundred feet in length with ponds covering from
twenty to sixty acres of land. 1t also contains many
acres of beaver meadows, many lodges burrows, and
artificial canals dense forest oyerspreads the land
broken only by the beaver meadows and the clear
ings made by miners. The prevailing trees on the
margin Of the stream are the tamarask and the
spruce. The white and yellow birch, the maple,
poplar and ash, are found upon the rising ground
and the hills in the rear are covered with the sugar
maple, oak and several species of pine Among the
bushes are the willow, the alder and the cranberry
The principal structure of the beaver is the dam. In
point of time it precedes the lodge since the floor OF
the latter and the entrances TO its chamber
struced with reference to the level of the water
the pond. The object Of the dam is the formation Of
an artificial pond, which place of refuge.
and connection to their lodges and their burrows
IN the bank As the level of the pond must rise from
one to two feet above the entrance to the lodge in
order to protect the animal from pursuit and capture
this level must be subject to their immediate control
Some Of these dams extensive that they could
not have been the work of a single pair, single
family Of beavers. But it does not follow that sew
era families unite in colony for the joint consruc
tsn of dam. On the contrary the larger structures
have been the growth Of a series of years. slowly
built up by poddng industry till they reached that
size which exhausted the capabilities Of the situa
tion after which they were maintained for centuries
by constant repairs. 1t is probable that they were
commenced by single pair, or a single family of
beavers and when by the gradual increase of the
DAM the pond had become large enough for more
than one family Others took up their residence upon
It. and afteTward contributed by their labor TO it's
maintenance. There is abundant evidence, In the
opinion Of the author to show that these dams have
existed IN the same places for thousands Of years,
and that they have been maintained by system Of
continuous repairs.
In external appearance, there two distinct kinds
of dams, though they all constructed on the
same principle. One is made of sticks and poles in
terlaced upon ths lower face with an embankment
of earth intermixed with the same materials on the
H. 4boI bfol