368 
ANIMAL INTELLIGENCE. 
overstocked, some of the beavers migrate. The Indians 
say that in their local migrations the old beavers go up 
stream, and the young down ; assigning as a reason that 
in the struggle for existence greater advantages are 
afforded near the source than lower down a stream, and 
therefore that the old beavers appropriate the former. 
But although lodges may thus be vacated by the old 
beavers, they are not left tenantless ; their lease is, as it 
were, transferred to another beaver couple. This process 
of transference of ownership goes on from generation to 
generation, so that the same lodges are continuously 
occupied for centuries. 
These lodges, which are always constructed in or near 
water, are of three kinds — the island, bank, and lake 
lodge. The first are formed on small islands which may 
happen to occur in the ponds made by the beaver-dams. 
The floor of the lodge is a few inches above the level of 
the water, and into it there open two, or sometimes more 
entrances : — 
These are made with great skill, and in the most artistic 
manner. One is straight, or as nearly so as possible, with its 
floor, which is of course under water, an inclined plane, rising 
gradually from the bottom of the pond into the chamber; while 
the other is abrupt in its descent, and often sinuous in its 
course. The first we shall call the ‘ wood entrance,’ from its 
evident design to facilitate the admission into the chamber of 
their wood cuttings, upon which they subsist during the season 
of winter. These cuttings, as will elsewhere be shown, are of 
such size and length that such an entrance is absolutely neces- 
sary for their free admission into the lodge. The other, which 
we shall call the ‘ beaver entrance,’ is the ordinary run-way 
for their exit and return. It is usually abrupt, and often wind- 
ing. In the lodge under consideration, the wood entrance de- 
scended from the outer run of the chamber entrance about ten 
feet to the bottom of the pond in a straight line, and upon an 
inclined plane ; while the other, emerging from the line of the 
chamber at the side, descended quite abruptly to the bottom of 
the moat or trench, through which the beavers must pass, in 
open water, out into the pond. Both entrances were rudely 
arched, with a roof of interlaced sticks filled in with mud in- 
termixed with vegetable fibre, and were extended to the bottom 
