192 



BRANCH VERTEBRATA. 



FIG. 331. 



more through some foreknowledge on their part of the 

 amount of rain-fall during the coming winter, is not sus- 

 tained by careful 

 observation. 



The Beaver 

 was once abun- 

 dant in North 

 America, but it 

 retires before civ- 

 ilization, and is 

 fast becoming ex- 

 tinct in this 

 country as it is 

 becoming in Eu- 

 rope. Its broad 

 tail and webbed 

 hind feet enable 



Cas'tor can a den' sis. American Beaver. ( T V) 



it to swim with 

 great ease. The 



enamel of its incisors is very hard.* It is noted for its 



ingenuity in building its habitations. \ 



* " The Indians, before the introduction of iron among them, were accustomed 

 to use these as chisels for working wood and horn. A tame Beaver will take an 

 apple in its forepaws, and, by dexterously turning and pressing it against its 

 incisors, pare it as readily as if the work had been done with a knife." Wood. 



t If the place chosen is by stagnant water, the Beaver at once commences 

 building on the bank, with lower entrances from the water; but if it is a run- 

 ning stream, a large company combine to build a dam, in order to keep the 

 water at the same level. G-oing up stream they gnaw off trees one to twenty or 

 more inches in diameter. These they float down to the spot selected, and, laying 

 them crosswise, fill in the interstices with mud and stone which they carry be- 

 tween their forepaws and chin. When the water is high enough to prevent 

 freezing to the bottom in winter, they separate into small families, and build 

 their houses against.the dam or the adjoining bank. The entrance is beneath 

 the water, and the vaulted roof is well plastered with a thick coat of earth, to 

 protect against the wolverine. When they dive they always slap with their tail, 

 and also when upon the tops of their houses inspecting them, or about their 

 work. This has given rise to the absurd idea of their using it for a trowel to 



