OBDEK OF BODENTIA. 
471 
fore, and are fully webbed. Owing to the deep separation 
. of the fingers, and the existence of certain fleshy tubercles, 
placed on the lower face of the extremities, they fulfil to some 
extent the functions of thumbs, those in front more especially. 
The muzzle is prolonged a little way beyond the jaws, and 
the nostrils are remarkably mobile. The ears are also movable ; 
they do not show much, and the animal has the faculty of placing 
them close to its head when it dives, so as to prevent water 
entering the auditory passage. Its coat is well adapted to 
the requirements of an aquatic life, and is composed of a 
fine thick woolly substance, which lies close upon the skin and 
is impervious to water. This first covering is hidden under 
long, silky, and glossy hair. The Beaver is about a foot in 
height and two feet in length, not including the tail, which 
is about one half the length of the body. 
We have already stated that Musk-Rats combine to construct 
habitations in close proximity to one another. The Beaver 
affords us a still more striking example of the love of associating 
with its own race, for, when practicable, they invariably live in 
numerous societies. 
Beavers are essentially aquatic; they swim with great ease ; 
in their hind feet they possess effective propelling power, and in 
their tail an excellent rudder. Countries intersected with lakes 
and rivers are, therefore, the localities in which they are found, 
such as the unfrequented solitudes of North America and Canada. 
Before the advent of the White Man they were universally spread 
over the northern portion of that continent. 
A feature to be noted in the habits of the Beaver is its extreme 
cleanliness. It will not suffer the slightest trace of filth to remain 
on the floor of its chamber. In captivity it preserves this 
characteristic. Buffon, who kept one, says that when it was shut 
up for too long a period, it deposited its excrement near the door, 
and that, as soon as it was opened, it hastened to eject it.* This 
dread of filthiness appears to be owing to the exquisite sensibility 
of its nasal organs. 
The Beaver does not build a house when the conditions of 
existence cease to demand it. This explains why the surviving 
* Having for some months possessed three tame Beavers, whose habits I closely 
studied, I can testify to the correctness of this statement. — Ed. 
