84 TEXT-BOOK OF ZOOLOGY 



that in North America these dams sometimes attain to a length of about 

 600 feet, and a height of from 7 to 10 feet, with a thickness of from 13 to 

 20 feet at the bottom, and 3| to 7 feet at the top. The beavers which 

 still exist in Germany no longer construct dams of such extent, and 

 they have also given up building "castles." 



Family 3: Mice (Muridae). 



The Marmot, or Hamster (Cricetus frumentarius). 



' (Length from 10 to 12 inches.) 



This animal is a native of the steppes which has followed man into 

 the ploughed fields. It is now found from the Ural to the Vosges. In 

 Central Germany it has already frequently made its appearance as a 

 pest. It avoids a sandy or moist soil. Its multicoloured skin, in 

 which a brown-yellow tint predominates, was evidently a safe pro- 

 tection on the steppes against its enemies. Not being able to run 

 as fast as the hare, it seeks protection underground. It digs its 

 hole in the same way as the badger (which see) ; this explains many 

 other similarities between the two animals, the body being thick set 

 and sturdy, the feet short, and the claws sharp. The dwelling-place is 

 padded with soft vegetable materials, and lies at such a depth below the 

 ground as not to be reached by the plough. From it a vertical and a 

 sloping passage lead to the surface. Both these passages are bent at 

 their lower ends. (Why ? What different purposes do these two passages 

 probably serve?) Besides these, one or more passages lead from the 

 dwelling chamber to the storerooms. The dentition of the marmot is 

 almost exactly the same as that of the squirrel (which see). During 

 spring and summer it feeds on all kinds of vegetables, but when the 

 corn ripens it feeds entirely on grain Since grain, peas and beans do 

 not spoil during the winter, it carries a store of these (often amounting 

 to half a hundredweight) into its dwelling. By means of its very agile, 

 hand-like fore-feet it bends down the blades and bites off the ears with 

 its incisors ; it then, with its paws, draws the ears several times through 

 its mouth, at the same time, with its tongue, pushing the grain thus 

 pressed out into its large cheek-pouches, which extend to near the 

 shoulders. Not being able, however, to carry in sufficient grain for 

 the whole winter, it sleeps through a great part of that season. After 

 having fed abundantly off its store (why?— see bat), and carefully 

 stopped up with earth the entrances to its dwelling, it betakes itself to 

 rest. With the approach of spring it re-awakes. As the fields, however, 

 cannot as yet supply it with sufficient food, it consumes the rest of its 



