From the latter part of summer onwards dead Shrews are quite common objects of the countryside; and various theories have been set up to explain the phenomenon, for these dead bodies are mostly without any signs of maltreatment, either by tooth or claw. It has even been attributed to an autumn epidemic afflicting Shrews alone; and to the influence of fear caused by a thunder-clap or the mere breaking of a twig near by. But apart from this mysterious mortality, Owls levy a heavy toll upon the Shrew, as is evident from the indigestible "casts" thrown up by these birds. Other birds of prey, such as the Kestrel, are known to take their share, and a further considerable number are claimed by Magpies, Jackdaws, Stoats, Vipers, and Smooth Snakes. Then, again, numerous males fall victims to the jealous fury of their own sex, which leads to fierce and fatal battles. But, as already stated, there are seldom any indications of such encounters on the bodies of these autumn dead, and the only conclusion that appears tenable is that they have died from what a coroner's jury would term "natural causes."
Mr. Lionel Adams, who has made special investigations into this matter, suggests that the natural cause is senile decay. He points out that young Shrews moult before winter, the process beginning in September and being completed by November, getting a darker and thicker coat than the light brown one they have worn hitherto. The progress of the change can be watched. It begins on the lower part of the back and extends gradually to the neck, head and face. In spring this darker coat is exchanged for a shorter and lighter one. But in their second autumn there is no resumption of the winter garb! The natural span of a Shrew's life is fourteen months as the maximum; and Nature does not go to the expense of winter clothing for creatures that will not live to wear it.
So small a body as that of the Shrew does not appear to require much food to keep it going; but the character of the food counts, and apparently insects are not very sustaining. The insect-eater must pursue his prey almost incessantly. We have proofs of this in the ceaseless activity of insectivorous birds, the Mole, the Bats, and the Hedgehog—all insectivorous. Mr. Adams found that, in captivity, a Shrew would gorge for half an hour, then have to sleep for a similar period before renewing its feeding with the same energy. In this case the food was all provided and had not to be chased; and the Shrew was willing to eat the flesh and pick the bones of one of its own kind. In thirty-six hours it consumed food of various kinds equal to nearly four times its own weight. If food is not obtainable for a few hours, the Shrew dies. This excessive demand of the stomach causes the Shrew to be active both night and day. It is fond of carrion, and has frequently fallen a victim to traps baited with bread, cheese, nuts or apple; and, as Mr. Pocock reports, with plum-pudding. He sleeps with the long flexible snout tucked between the forelegs under the chest.
The Shrew's dental formula is i 4/2, c 1/0, p 2/1, m 3/3 = 32. The summits of the teeth are red-brown, and the almost horizontal lower incisors are encircled by those of the upper jaw.
The Common Shrew is found throughout Great Britain but not in Ireland. Its vertical range is from sea-level certainly to 1500 feet, at which height it has been found in Cheshire by Coward and Oldham. It probably goes higher in our mountain regions, for on the Continent it has been recorded at 6000 feet. It is active all the winter among the dead leaves in some thick hedgerow, where it searches for hibernating insects which are plentiful in such covers. The rambler at this season may have his attention called to the Shrew by its shrill squeak, but like that of the Bats it does not impress all ears.
A form found in the Isle of Islay has been separated as a distinct species under the name of Sorex granti.
It is strange that so inoffensive a creature should have been the subject of superstitious malignity in the past. It was reputed to cause lameness by merely running over the foot of man or beast, and as an antidote a Shrew was plugged into a hole bored in an ash tree from which thereafter a twig passed over the afflicted part would effect a cure. Readers of Gilbert White will remember his description of the Shrew-ash that formerly stood "at the south corner of the plestor" at Selborne. The evil reputation of the Shrew was much more ancient than White's day, for the Rev. Edward Topsell, who wrote a "Historie of Four-footed Beastes" (1607), says of it—"It is a ravening beast, feigning itself gentle and tame, but, being touched, it biteth deep and poysoneth deadly. It beareth a cruel minde, desiring to hurt anything, neither is there any creature that it loveth, or it loveth him, because it is feared of all."
Lesser Shrew (Sorex minutus, Linn.).
The Lesser or Pigmy Shrew is the smallest of all British mammals. It may be described roughly as a smaller edition of the Common Shrew, and until recent years was considered to be only the juvenile form of that species, for which, no doubt, it is still mistaken frequently. It appears to be widely distributed in Britain, but is local, the areas in which it occurs being limited and patchy when marked on the map. These are mostly in wooded districts, but extend from sea-level to the tops of our highest mountains, for it has been found on Ben Nevis at a height of 4,400 feet. In Ireland, from which the Common Shrew is entirely absent, its place is taken by the Lesser Shrew, though it is not nearly so abundant as the Common Shrew is in Britain.
Seen side by side these two species are sufficiently distinct, but apart they may be taken as identical. The earlier British naturalists had not learned to discriminate one from the other, and even Bell, as late as 1837, does not mention the Lesser Shrew, though in the second edition of his work (1874) it appears in a description by Alston. If we take average length of head and body in an adult Common Shrew as three inches, we shall find that a similar individual of the Lesser Shrew measures only two inches and a quarter—a reduction of 25 per cent. The hind foot without the claws in the Common Shrew is half an inch, but in the Lesser Shrew it is one-sixth less. The actual length of the tail is about the same in both species, but proportionately there is a difference, for whilst that of the Common Shrew only equals half the length of head and body, in the Lesser Shrew it is equal to two-thirds. But it has been held that the length of the hind feet alone is distinctive, and that "any Shrew in which these reach or exceed 12 millimetres may be set down as of the larger species."