J ul y . 1 9 1 o. The Irish Na in ra lis t. 121 



THE AUTUMNAL MORTALITY AMONG SHREWS. . 



BY C B. MOFFAT. 



On the vexed question of the cause of the autumnal mortality 

 so prevalent in the Common and Eesser Shrews {So7rx araneits 

 and 5. viimihcs), Mr. Lionel E. Adams has brought forward a 

 most interesting and original h3'pothesis in a paper^ which he 

 recently read to the Manchester Literar}- and Philosophical 

 Societ}'. The question is highly deserving of the notice of 

 Irish naturalists, because it opens up a new field for inquir}' as 

 regards the life-history of one of the few mammals found 

 in Ireland. It is well known that the Common Shrew of 

 Great Britain is absent from our fauna ; but the Lesser Shrew 

 is, in all probabilitj^, a more common animal in Ireland than 

 in England. 



Putting aside for plain and (I think) sufficient reasons most 

 of the theories that have been hitherto broached as to the 

 cause of the so-called " epidemic '' which leads to so many 

 shrews being seen dead on roads and footpaths in autumn, 

 Mr. Adams adduces the simple and novel suggestion that the 

 animals have died of old age ! And his suggestion, which is 

 supported by a strong though not perhaps conclusive argu- 

 ment, embraces as a necessary part of itself the still more 

 remarkable theory that a shrew can only live for about a year 

 and two months. So brief a span of life as this seems scarcely 

 credible, but the facts which Mr. Adams adduces in favour of 

 his hypothesis deserve to be looked at closely. 



Mr. Adams has for many years been in the habit of trap- 

 ping small mammals, and has taken many specimens of the 

 Common Shrew — with a considerable though much smaller 

 number of 5. minutus — at all seasons of the year. In dealing 

 with this subject he incidentally lefers to the old belie! that 

 shrews hibernate, and it is only fair in behalf of Irish zoolo- 

 gists to point out an error into which he falls in stating that 

 Mr. J. G. Millais — in his work on the " Mammals of Great 



^A Hypothesis as to the cause of the Autumnal Epidemic of the 

 Common and the I^esser Shrew, with some Notes on their Habits, by 

 Lionel E. Adams, B.A., Proc. Manchester Lit. and Phil. Society, i909-'io, 

 vol. 54, Pt. ii. 



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