136 



THE NATURE BOOK 



In point of fact, however, the lower jaws 

 and teeth of mice admit of considerable 

 movement, both conjointly from one 

 side to the other of the mouth, and sepa- 

 rately, to varying distances from one 

 another. They form a tool of which sup- 

 pleness is a distinguishing feature. This 

 tool, however, is singularly effective in 

 chiselling all kinds of vegetable matter, 

 and it is possible that its side and cross 

 movements are an advantage to the mouse 



LOWER JAWS OF LONG-TAILED FIELD MOUSE (1); RED-BACKED 

 MEADOW MOUSE (2); AND SHORT-TAILED MEADOW MOUSE (3). 



in dealing with fixed obstacles. It is 

 noticeable in this connection that a wooden 

 cage for rats or mice need not be metal 

 lined throughout. It is only necessary 

 to protect the right-angled junctions of 

 the sides, top, and bottom, for the rat 

 or mouse can get no grip on the flat with 

 his upper incisors, and consequently 

 cannot gnaw it. 



There are interesting variations in the 

 form of the lower incisor teeth in the 

 different species of mice. In the Long- 

 tailed Field Mouse we find a tooth thicker 

 (front to back) than it is wide, with a 

 long, hollowed bevel — a carver's chisel, 

 in fact ; in the Red-backed Meadow Mouse 

 a slightly wider tooth with similar bevel 

 — a cabinet-maker's chisel ; and in the 

 Short-tailed Meadow Mouse a tooth whose 

 width is about equal to its thickness, and 

 whose bevel is short and abrupt — a car- 

 penter's chisel. A long bevel and narrow 

 cutting edge are an advantage in dealing 

 with hard material, owing to the lesser 

 substance of the shaving. It is not sur- 

 prising, therefore, to find that the Red- 

 backed Meadow Mouse is, like the Long- 

 tailed Field Mouse, a confirmed nut- 

 cracker ; and that, where the bark of trees 

 is attacked by mice, it is probably one 

 of these two species which is the culprit. 



In the spring of 1902 I excavated in a 

 neighbour's orchard the local habitations 



of two small rodent communities. One 

 was tenanted by Long-tailed Field Mice, 

 the other by Red-backed Meadow Mice. 

 They were situated within fifteen yards 

 of each other, and appeared to be con- 

 ducted on similar lines. In both cases 

 there were, as far as I could determine 

 in the intricacy of the roots, three en- 

 trances. In both cases these entrances 

 terminated in a double compartment, sleep- 

 ing-room and store, some eighteen inches 

 below ground-level. 

 In both cases the 

 community consisted 

 of five adults, and 

 in both cases the 

 store was entirely 

 composed of cob- 

 nuts. The Field Mice 

 had ninety-eight, the 

 Meadow Mice ninety- 

 three, so tightly 

 packed that it was 

 difficult to dislodge them with the fingers. 

 No doubt this was due to a gradual sub- 

 sidence of the roof of the burrow, which 

 the mice themselves would be quite cap- 

 able of remedying. The nuts were intact, 

 and I failed to discover any empty shells 

 either in the burrows themselves or in their 

 vicinity. This looked as if the stores had 

 not yet been drawn upon, for the nuts were 

 of excellent quality; and to those fond 

 of the nuts I would recommend the ex- 

 pedient of maturing them at an even 

 temperature as the mice do. 



The presence of such large stores natur- 

 ally roused my curiosity as to how the 

 nuts were originally collected and handled. 

 Experiments with captive Meadow Mice 

 showed me that at least three methods 

 of transport were employed. Their usual 

 practice is to take the pointed end of the 

 nut between their teeth and to jump along 

 with their heads held high. Sometimes, 

 however, they wedge it between their 

 chin and fore-legs, and sometimes they 

 trundle it before them. 



Owing to the all-round effectiveness of 

 his teeth and to his catholic taste in 

 vegetables, the Red-backed Meadow Mouse 

 can make his presence felt. 



" lis fur is red as the red chestnut, 

 And it is blithe and slim ; 

 It leads a life most innocent 

 Within the forest dim." 



