THE SHREW MICE 



309 



shown by the fact that the females of 

 our three British species contrive to be 

 similar!}' odoriferous without their assist- 

 ance. 



Shrew ]\Iice of both sexes })()ssess 

 what are known as " hibernating " glands. 

 These de\-elop as winter approaches, and 

 disappear completely in the spring. They 

 are situated on the ani- 

 mal's shoulders, and con- 

 sist of four symmetrical 

 tongue-shaped masses of 

 yellowish tissue, each 

 about 16 mm. long, antl 

 at its widest portion 8 mm. 

 broad. What function 

 they perform is uncertain 

 — it is even uncertain 

 whether they are glands 

 at all, or merely masses 

 of fat. It is evident, how- 

 ever, from their constant 

 and symmetrical form, and 

 their periodic appearance 

 and disappearance, that 

 they are, in some way, 

 definiteh' connected with 

 the animal's winter 

 economy. 



Until quite recently it 

 was the fashion to main- 

 tain that Shrew Mice hi- 

 bernated ; it is now the 

 fashion to assert, with 

 equal confidence, that 

 they do not hibernate. 

 Much, of course, depends 

 on what is meant by hibernation, but 

 even when we allow that the word is 

 open to more than one interpretation, 

 we can hardh^ settle the question \\ath- 

 out close obser\-ation of living Shrew 

 Mice during the winter months. I do 

 not know that such observation has ever 

 been accomplished. For my own part I 

 have found Shrew Mice difficult to keep 

 alive for more than a few months in 

 spring and summer, and I have ne\'er 

 been able to tide them over a winter. 



At the same time I incline strongly to 

 the opinion that a Shrew Mouse, faced 



by a rapid diminution of his food supply 

 such as would ine\itably occur in a hard 

 winter, must either relajise to a torpid 

 condition — in which he can subsist on rare 

 and occasional meals — or die. I ha\'e 

 more than once recently observed a Shrew 

 Mouse burrowing in soft soil, and liis 

 tunnel, though small, is as neat as that 



1. The remarkable "hibematinS Slands " of the Shrew Mouse, which develop 

 just beneath the skin on the animal's shoulders towards the winter and 

 disappear entirely in the spring. 



2. Front view of head of dead Shre\y Mouse, showing the remarkable 

 development of the whiskers (tiliiissu), 



3. A Shrew Mouse skin with the fur parted to show the scent glands on 

 the animal's sides. 



of the ]\Iole, but his burrowing powers 

 are ol>viously limited by his size, and 

 the hibernating glands, whether they 

 be true glands or merely masses of fat, 

 afford strong presumptive evidence that, 

 as the cold approaches, his organisation 

 is profoundly modified. 



I have occasionally trapped Shrew Mice 

 during hard weather, but on consulting 

 my records I ha\e found these occasions 

 so rare, comparatively, that I have 

 modified my previous oijinion that Shrew 

 ]\Iice were acti\e from year's end to 

 year's end. 



Douglas English. 



