FOUR-FOOTED FORESTERS THE SQUIRRELS 



43 



since it appeared. As it stands, we find in it over 40 

 different kinds of chipmunks enumerated as occurring 

 within the boundary lines of the United States. This 

 includes species and subspecies, and does not take into 

 consideration those which are extralimital or confined to 

 Mexico or Canada, as the case may be. 



A good deal has been written about chipmunks, and 

 they are fully worthy of all the biographies that have 

 appeared about them (Fig. 1). In various works they 

 are not only known by this name but referred to as hack- 

 ees, or ground-hackees, striped squirrels, striped ground 

 squirrels, and ground squirrels. All are small mammals 

 of marked intelligence, and if properly reared and treated 

 make very affectionate pets. In them the cheek pouches 

 are highly developed, each consisting of a hairlined pouch, 

 occupying quite a space on either side of the mouth, with 

 the opening to the front. One of these pouches will hold 

 several large nuts, and it is a remarkable sight to see one 



the death of their owner ; for, should any blow, given in 

 the mouth, turn either of the upper pair to one side or 

 the other, so that the edges are not continually worn off 

 evenly and regularly by the lower incisors, the misplaced 

 tooth or teeth the upper ones will continue to grow in 

 a curve, backwards, until their sharp edges come in con- 

 tact with the roof of the mouth. In that part of the 

 squirrel's skull the bone is quite thin and not strong 

 enough to stop the advance of the tooth. The result is 

 that it not only, in due course, pierces the palate, but 

 grows backwards into the brain, eventually causing the 

 death of their hapless owner. A similar misfortune has 

 been noted in the case of rabbits. 



Chipmunks have another use for their cheek pouches. 

 When they construct their most ingenious burrows, they 

 use them to carry away the loose dirt resulting from their 

 digging, to hide it so it will never be suspected where it 

 came from. They are also careful not to wear a path 



ATTENTION ! 



Fig. 9. This is the Red Squirrell in the attitude of attention; and squirrels, as a rule, have many different poses, each being characteristic 

 of them and very distinct, as the feeding pose, when "barking," when burying a nut, sunning itself, and others. 



of these little fellows making off to its burrow on a run 

 with a big butternut in each cheek. It suggests a little 

 animal with a head three times too big for its body. Some 

 rodents have these pouches more to the outside, where 

 their openings may be clearly discerned, as is the case 

 with the gopher rats. 



Another interesting structure in the squirrel family is 

 that of the incisor teeth. There are two of these in either 

 jaw a pair above and a pair below. They may best be 

 studied in the skull of any large rodent, as a beaver, a 

 jack-rabbit, or a muskrat. The skull selected here is that 

 of a South American Coypu. This animal died in the 

 National Zoological Park a few years ago, and the skull 

 was presented to the writer. (Figure 3.) Note the two 

 large upper and lower incisors ; these, by grinding upon 

 each other, keep the four cutting edges as sharp as razors. 

 In the case of nut-eating mammals like our squirrels, 

 this is extremely essential. These incisor teeth keep con- 

 tinually growing, as they are worn off during the life of 

 the individual the upper pair downwards and the lower 

 pair upwards. Curiously enough, they sometimes cause 



leading to the entrance of their burrows, for it would 

 be a guide to their retreat for some of their numerous 

 enemies. 



In places where chipmunks are abundant, they are 

 found to be extremely sociable little animals among them- 

 selves, playing together, until the approach of the coldest 

 weather of the year, when they hibernate as do so many 

 other small mammals occurring in the higher latitudes 

 of our country. 



One of our earliest writers on the chipmunk has said 

 that "In the autumn this creature may be seen around 

 the fields of Indian corn, and in the walnut and chestnut 

 woods, filling his ample cheek pouches, and carrying off 

 his store to his granaries. His hole is generally placed 

 near the roots of trees, or in a decayed stump, or among 

 a heap of rocks, or in a bank of earth, and usually near 

 the forests or fields from which he draws his supplies. 

 Sometimes his retreat has two or three openings ; it 

 usually descends almost perpendicularly at first ; then it 

 rises with one or two windings, and at last, at the distance 

 of eight or ten feet, terminates in a chamber lined with 



