224 A. HAWKS — THE EE-H^TEODUCTION' 



highest, and forms a cutting edge, while the bone supports it 

 behind. Thus the beaver's teeth are chisels, but possessing a pro- 

 perty which no art of man can give to the carpenter's chisel ; for 

 the cutting-teeth of the beaver have not roots consisting wholly of 

 bone, as in the teeth of most animals, and indeed in the grinders 

 of the beaver itself. They are inserted deeply in the jaws, in a 

 peculiar kind of socket which exists only during dentition in the 

 teeth of other animals. These sockets continue gradually to produce 

 the teeth in such a manner that both bone and enamel grow at the 

 root as fast as they are worn down at the point, and thus the teeth 

 remain in good condition during the whole life of the animal. The 

 edges of the teeth are directly opposite each other, so that they 

 bite clean. 



"With these weapons the beaver attacks a tree, which he brings 

 down by cutting notches through its trunk, first marking the tree 

 all round. The trees felled are made to fall directly towards the 

 stream — that is, unless the wind upsets the beaver's calculations, 

 which it does sometimes. In one case a tree had fallen just across 

 the stream, so that the branches which fell undei-most were made 

 use of as framework for a dam. This is a very curious instance ; 

 for the top of the tree, as it lies, just reaches the bank of the 

 stream farthest from the root, and Black, the keeper, told us that 

 it has often been discussed whether the beaver knew that it woiild 

 do so before the tree was attacked. I can say no more than that 

 certainly it has fallen, or has been made to fall, exactly in the 

 proper direction to be utilised for a dam, and the branches have 

 been left on it and used for that purpose. Of course it is perfectly 

 probable that the tree was, in the first instance, cut down for food, 

 or for other purposes, and that when it was found to be useful for 

 a dam, the intention was changed ; but if so, the change of intention 

 is not less remarkable than the other supposition. 



There is another case for remark. The trees usually fall directly 

 towards the stream, so as to lie handy for the beaver's purpose, but 

 an instance to the contrary was pointed out to us. Two trees have 

 been felled so that their tops, though pointing towards the stream, 

 do not do so directly, but diverge outwards, one inclining to the 

 top and the other to the lower end of the enclosure ; the reason for 

 this is that two other trees were standing between them and the 

 stream, so that if these trees had fallen directly towards the stream 

 they would have been caught in the branches of those other trees. 

 Why then, it may be said, did they not fell the other trees first ? 

 There was no doubt a reason, for beavers appear to do nothing 

 without ; probably those trees were not such as they use for food, 

 for they know what to eat and what to avoid. There is also 

 another possible reason. I have an impression, though I do not 

 find in my notes, that the trees which stood in the way were dead, 

 and beavers will not touch a dead ti-ee, neither, according to Black, 

 will they interfere with one another's work. If one begins to cut 

 down a tree he finishes it alone. Thus each works for his own 

 hand, but all for the good of the community. If, again, a beaver 



