150 RODENT WATER TRESPASSERS. 



It may at first sight appear rather strange that the 

 possession of very large teeth should be necessary in 

 order that the Beaver may retain its position as a 

 water trespasser. Yet, were it not for these wonder- 

 fully powerful weapons, the beaver would soon perish 

 off the face of the earth. A certain depth of water is 

 absolutely necessary for its existence ; this depth 

 cannot be secured without the use of dams ; and dams 

 cannot be made without the assistance of teeth that 



SKULL OF BEAVEK. 



are large, sharp, and powerful enough to fell the trees 

 which make the foundation of the dam, to cut off the 

 boughs, and to strip them of the bark. These teeth 

 are, therefore, even for a rodent animal, of very great 

 size and strength. They are so powerful that they 

 can cut in two with a single bite a strong walking- 

 stick, and the grooves which they leave upon the trees 

 are so deep that they are often mistaken for the marks 

 cut by the Indian tomahawks. 



The strength and size of the teeth may be judged 



