Bulletin
ov Tiir.

Illinois State Laboratory
OF

Natural History

Ukbana, Illinois, U. S. A.

STEPHEN A. FOKBES, Ph.D.. L,I..D.

DiRBCTOR

Vol. IX. October, 1910 Articles I-II.

ART. r. ON THE COMMON SHRRW-MOL,E IN ILLINOIS

BY

FRANK ELMER WOOD, A. 15.

ART. II. A STUDY OF THE POOD OP MOLES IN ILLINOIS

BY

JAMES A. WEST, A. M.

NATI/fiAl iuSlOii :m^

S^P 1969



ERRATA AND ADDENDA

Page 54, lines 3 and 2 from bottom, and elsewhere in Article III. for Cassia

chainaechrista read Cassia chamaccrista.

Page 62, between lines 4 and 5 from bottom of table insert Erigeron annuus.

Page loi, table, after Croloii glandulosus read var. septentrionalis: and for

Eijuisettim laeinyatum read Eqnisetum bycmale var. inlermedium.
Page 131. line 3, for coerulea read caerulca.

Page 138, last line, for Zi::a read Zizia.

Page 141, line 21 from bottom, dele Diodia teres.

Page l6g. between lines 3 and 4, insert as follows

:

Erigeron annuus (L.) Pers. An interstitial in the liunch-grass association

in the Hanover area.

Page 177, line 5, for casti^'ard read iveslzvard.

Page 209. line 3 from bottom, for copalina read copallina.

Page 210, line 13 from bottom, for Diospyrus read Diospyro'i.

Page 211, line 5, for Foresteria read Foresticra.

Page 256, line 3 of table, for Dr. H. M. Pepoon read H. 5". Pepoon.
Page 278, line 16, the fifth word should be in Roman type.

Page 286, line 6 (second column), page 295, list of secondary species (second
column), and page 353. line 8 from bottom, for hiematis or hiemale read hye-
mnte.

Page 313, line 4 from bottom (first column), for pedicularis read pcdicularia.

Page 315, line 10, second column, for Apoeynum read Apocynum.
Page 323, line 3 from bottom, for Cyperus read Scirpus.

Page 330, line 14, for virginianum read inrginicum.

Page 336. lines 3 and 2 from bottom, for virginicum read virginianum.
Page 337. line 2 from bottom, for philadelphicum read philadelphicns.

Page 339» in first list of invading species, for Rhus hiria read Rhus typhiua.

Page 351. line 4 from bottom, for .verophtic read .verophytic.

Page 355, above line 6 from bottom, insert Scirpus heterochaetus Chase.
Page 356, line 14 from bottom, for Symlocarpus read Symplocarpus.
Page 360, line 14, for Pirus read Pyrus.
Page 362, after line 7, insert Acer saccharinum L.

Page 363, line 2 from bottom, for quadiflorum read quadriflorum.
Page 365, line 14, for Ihapus read thapsus.
Page 369, last line, for Tanecelum read Tanaceium.
Page 417, line i. dele the.

Page 497, line 9 from bottom, for neglible read negligible, and in foot-note, for
Auslall read Anstalt.

Page 498, line 4 from bottom, for Lockport read Chillicothe.

Page 500, line 13 from bottom, after up insert in.

Page 5or, line 2 from bottom, for dissolving read dissolved.

Page 504, line 23, for gryina read gyrina : line 17, for dentata read knickerbockeri.
Page 506, line 11, for vernata read ternala.

Page 507, line 3 from bottom, for Macon read tt'asoi.

Page 513, line 19, for Nepa read Zaitha; line 18, and page 517, line 13 from bot-
tom, page 520, line 12 from bottom, and page 532, line 4, read naid or naids
for naiid or naiids.

Page 517, line 6 from bottom, for pondiveed read pickcrel-iveed.



Page 519. for first sentence of last paragraph read as follows:

We have no exactly comparable chemical data for July; but analyses

for August give percentages of saturation for Morris and Marseilles as follows :

20.4 per cent, at Morris on the nth and 11 per cent, at Marseilles on the 12th;

16.35 P<^r cent, at Morris on the 22d and 23d and 7.4 per cent, at Marseilles on
the 24th and 25th.

Page 521, line 6 from bottom, and page 529, line g, for chrysoleucas read cryso-

leticas.

Page 525, line 22, and page 536, lines 21 and 24, for Ekmann read Ekmnn.
Page 532, line i, for Ancyclus read Ancylus.
Page 551, line 7, for 00 read 572.

Page 615, second line above foot-note, for 106 read 94.

Page 616, line I, for the second Biindeln read Bilndel; line 2, for Biindeln read
Biindcls; line 3, for ausscrn read ausscren; line 6, for sweierlie read sweierlei.

Page 629, line 12, for kciii read kcincn.
Page 634, line 9, for untcrnommcn read untcninntincnen; and in line 14 from

bottom, after ;;/$ insert is fig.

Plate III, Fig. i, after the word mixed in legend insert consocies of the.

Plate IX, Fig. 2, dele the legend and read instead ; Root-system of Tephrosia
virgiiiiana, exposed by blowing of the sand.

Plate X, Fig. 2, dele the legend and read instead ; A blowout almost stabilized

by bunch-grasses, especially Leptoloma cognatum.
Plate XXXIX. for Calainogrostis read Calamagrostis.
Plate LIV. exchange places of cuts, but not the legends.
Plate LXXXV, for 7 read ye.



Article I.

—

On the Couimon Shrciv-nwlc, Scalopiis aquatkus

viachrinus (Rafiinsqiic), in Illinois. By Frank Elmer Wood.*

There are two species of moles in Illinois : one, the starnose mole,

Coiidylura cristata (Linnteus), is found sparingly in the northern

part of the state ; the other, known as the common or shrew-mole,

Scalofyus aqualictis (Linnjeus), is the one with which this paper deals.

It is distributed throughout most of the state, and apparently all our

specimens may be referred to the western subspecies machrinus (Raf-

inesque).

l"he general range of the species, under various forms, extends

over most of the eastern half of the United States. Its northern

boundary is a line running from the southern point of Maine west-

ward through New Hampshire, Vermont, New York, Ontario, and

Michigan, and thence northwestward to a point on the Red River of

the North near the Canadian boundary. Its western limit is near a
line from that point to the mouth of the Rio Grande. The mole is

found also for a short distance along the Gulf of Mexico, but not in

southern Florida. Over this range there is considerable variation in

size, color, and some other characters. In general, specimens from

the arid regions of the West are lighter in color than those from

sections in the east and south which have a moister climate. The
smallest variety is found in Florida, and, judging from data at hand,

specimens from Illinois attain the largest average size. In the At-

lantic States northern specimens average larger than southern ones,

and it is true in general for all states east of the Mississippi that

eastern specimens are smaller than western ones from the same lati-

tude. There appears to be considerable variation in size even within

the state as is shown by the following tables.

True gives the average length of six specimens from Illinois as

follows: total length, 188.7; head and body, 154-9; and tail, 33.8.

Apparently these specimens were all from the western border of the

state. This would indicate a gradual increase in size from east to

west across the state, and that the maximum size was reached near

or beyond the Mississippi River.

*Some matter on the mole, additional to that u.sed in the present article,

may be found in "A Study of the Mammals of Champaiffii County. Illinois,"

by F. E. Wood, published in May, 1910, as article 5 of Volume VIII of the

Bulletin of this Laboratory.



Measurements of Twenty-seven Adult Specimens from
Champaign County



Measurements of Specimens from Various Localities within the State



There is also considerable individual variation in color, not cor-

related with any other evident characteristic, or with peculiarities of

haljitat, so far as I have been able to make out. The fur, except on

the snout and extremities, is dense, fine, and silky, with but very little

slope, so that it offers little resistance to rubbing in any direction.

The hairs on the back attain a length of i cm. (.39 inch) or more,

becoming shorter on the under parts.

The general color corresponds to that called "haii'-brown" in

Ridgway's nomenclature. This is sometimes grayish, sometimes

\\armed to bister or sepia, and is always obscured by a shifting,

sheeny luster. Closer examination shows that the basal four-fifths

of each hair is kinky, and is plumbeous in color, while the distal fifth

is straight and bent at an angle to the general direction of the main
portion. The direction of this tip constitutes the greater part of

whatever slope there is to the hair. Under a low power of micro-

scope it will be found that the hairs are flattened, and that the color

of the basal portion is due to alternate black and translucent bands,

while the apex; is broader, lanceolate in shape, and contains a core of

l)rownisii-orange coloring matter. The chin, throat, upper surface

of fore paws, and wrists are much lighter, and often suffused with

shades vaiying from ochraceous to ferruginous, or even, in spots, to

a decided orange. The tail is whitish at base, nearly naked and pink-

ish at the tip, as is also the tip of the snout and the toes. Specimens
taken in spring often show patches of new fur replacing the old, and
the fur in these patches is shorter and darker than the old fur. The
snout is prolonged about 8 mm. beyond the lower jaw. It is flattened

and deeply grooved below, and is naked and truncate at the apex at an

angle of 45 degrees. This truncated surface looks upwards and con-

tains the nostrils. At the tip is a hard nail-like body. The upper lip

is split and represented by two thin folds in front. The long snout

of the mole is very flexible, and is in constant motion when the ani-

mal is in action. It is abundantly supplied with nerves and terminal

sense organs. The sense of smell and the sense of touch in the snout

must be, for the mole, the chief means of an accpiaintance with the

outside world.

The fore limbs are concealed to the wrist under the skin. The
fore paws are enormously developed. The toes, five in number, are

webbed their whole length, making the entire length of the palm

15 to 20 mm. (.6 to .8 in.). The width is still greater, being 20 to



25 mm. (.8 to i in.)- Thi.s great width is produced by a flap of skin

on the lower edge, tlie rigichty of which is maintained by an extra

sickle-shaped bone. The palm is margined with stiiT hairs. The nails

are stout, flattened, semicylindrical, and translucent enough to show
the bifid tips of the last finger bones within. The hind feet are of

normal size, five-toed, with nails that are flattened, hollowed below,

and rather slender. The tail is squarish, especially at the base.

The general impression given by the appearance of the amis and

shoulders of a mole stripped of its skin and superficial fat is that of

a wonderfully compact and powerful digging machine, to which the

animal is strapped by comparatively slender muscular bands. The
development of the muscles of the breast and shoulders has kept pace

with the massiveness of the bones. The pectoral muscles are attached

to a keel-like projection of the sternum, and by their thickness re-

mind one of the breast of a bird. Certain muscles of the shoulder

are also greatly developed, and in some of them it seems that muscu-

lar overgrowth has reached its limit.

Fig. 2. Part of skeleton of moi,e, showing
attachment of kore legs.

The thick fur hides the eye and ear, but they may be located if

the hair is cut off close. The eye appears as a protuberance, about

the size of a pinhead, 20 to 25 mm. ( .8 to i in. ) from the end of the

snout. If the skin at that i)lace is lifted up, the eye will be found



on the under side—a black speck between the skin and the skin

muscles. It is not within the bony orbit of the skull, but outside and

in front of it. Microscopic examination reveals an openin_a;- through

the sT<in over the eye, but it is dilticiilt to find without a lens. The

eye itself, though containing rudiments of the essential parts of the

nonnal mammalian eye, is so degenerate that distinct vision is im-

possible, and at most it can only serx'e to distinguish light from

darkness.

Owing to the fact that the shoulder bones and the attachment of

the fore limbs are so far forward of the usual position, the external

opening of the ear appears to be on the shoulder, though in reality it

is not misplaced with reference to the skull. There is no true pinna

or external ear, but the external auditory meatus is prolonged beyond

the head a few millimeters by a cartilaginous tube. Between the eye

and the ear is a protuberance containing vibrissre, and probably fimc-

tioning as an organ of touch.

The mole has thirty-six teeth. In each upper jaw there are three

incisors, one canine, three jjremolars, antl three molars. In the lower

jaw there are two incisors, no canine, three premolars, and three

molars. The two middle incisors in the upper jaw are large and seem

to resemble those of the rat and other rodents at first sight, but they

differ greatly in structure, having enamel on all sides, instead of only

in front like the rodents. The second and third incisors are small

and often missing. In the lower jaw the middle incisors are small

and the lateral ones of moderate size. The molars and premolars

fonn veiy irregular surfaces, the projections of the lower teeth fit-

ing into corresponding hollows in the upper teeth, and vice versa.

This construction of the teeth and the strictly up-and-down motion

of the jaws are well adapted to the chopping up of insects or other

animal food, but do not permit any grinding motion as is the case

with animals li\'ing on seeds, grain, or other vegetable food. On ac-

count of this structure of the teeth naturalists have been loath to be-

lieve that the mole e\-er eats vegetable food, for which its teeth seem

so ill adapted.

Although the shrew-mole rang^es throughout the state, there are

certain sections where it is rare or unknown. In most cases the cause

for this is not far to seek. Moles require a soil easily penetrated by
their burrows and containing an abundance of worms or insects for

their food. Evidently a soft, rich loam, not too thoroughly culti-

vated, is their ideal habitat, and such localities usually contain an
abundance of them. Stony or coarse gravelly soils are avoided, but



they are found in light sandy soils where ease of burrowing compen-
sates for the poorness of the subterranean fauna. They are in no
sense aquatic, so far as has been observed in this state. They may
be tempted, by an abundance of food, to run their burrows into low

ground, even into tracts submerged during parts of the year, but al-

most invariably such runs will l)e found to communicate with others

furnishing a retreat to higher ground. Burrows are often seen run-

ning down the bank of a stream or across the muddy shore of a pool,

nearly or quite to the water's, edge ; but I have never seen a fresh

opening under the water or, indeed, quite reaching it, except where
there had been a recent decided rise of the water-level. Undoubtedly,

like most mammals, moles can swim, but I doubt if our form ever

habitually enters the water for food.

The species has been taken, or reported on reliable authority, in

the following places within the state.



During a week's collecting in the vicinity of McHenry, in Mc-

Henry county, not a trace of a mole or of mole work was seen, and

apparently the farmers were quite unacquainted with either. More
recently, howe\-er, the presence of moles in that town has been re-

ported. Probably there are other sections of the state in which they

are rare or lacking, but we have no authentic record of such.

The burrows of the mole are almost always excavated, not by

bringing the dirt to the surface, but l)y pushing it aside. The method

seems to be as follows : The head is lowered and retracted—the flexi-

bility of the neck permitting this—the fore paws are thrust forward

in front of the nostrils, and by a sort of swimming motion the earth

is pushed aside, the head at the same time being advanced and raised.

The flexible snout is kept in continual motion, probably for exploring

rather than for loosening the soil, as was once thought. The mounds

of dirt thrown out are usually from burrows moderately deep. Pre-

sumably this, is done only when the animal finds it difficult to dispose

of the dirt otherwise. However, in central Illinois, I have never been

able to correlate the presence or absence of such mounds with hard-

ness of the soil. Possibly they are rather an indication of the depth

of the excavations. When present they are in general at the top of

vertical shafts ascending, not directly from the main tunnel, but from

a short lateral one. How the earth is brought to the surface is not

known.

Audubon and Bachman, in their great work on the quadrupeds of

North America, mention the finding of two nests with young, one

containing five and the other nine, and this observation seems to be

the sole basis for all statements on this point made by most writers

since. Kennicott's infonnant who reported a gravid female in Feb-

ruary with two young "clothed with hair" and about to be brought

forth must have made some mistake. There are four young moles in

the Laboratoiy collection a\'eraging over loo mm. iu length, but they

are still nearly hairless. The result of an examination of all females

in our collection accompanied with data of capture is shown in the

table on page 9.

These obsen'ations seem to indicate one litter a year, brought

forth in the latter part of April or early in May. All data available

for this state suggest that the average number in a litter is nearer

three to six than "from five to nine." In No. 38347 all six of the

teats bore evidence of being used.



RBsuws OF Examination of Female Moles in the Laboratory

Ace. No.



10

sistant in the State Laboraton' of Natural Histoiy, a reported injury

to corn by moles was assigned to him by Dr. Forbes for investigation.

The field work was chiefly done in the vicinity of Jacksonville, Illi-

nois, during corn-i)lanting time and while the grain was l:)eginning to

grow. Extensive trapping was done in corn fields, gardens, and vari-

ous neighboring fields, including pastures, fallow ground, and wood-

land. Corn was put in the burrows to see if the moles would eat it.

Moles were said by farmers where we worked to be much less com-

mon than usual, but a number were caught and their stomachs were

preserved for examination.

The injury done was limited chiefly to the edge of the field, mostly

within fifty feet and virtually all within a hundred feet of the mar-

gin. Moreover, it was much greater in those parts of the field next

an old hedge, a woodland, or pasture, or any uncultivated land,

where, of course, the tunnels of the moles were undisturbed. Very
little damage was done in the interior of large fields. .\lthough

moles work in corn fields all summer and fall, yet, so far as my ob-

servations go, the damage is practically all done within the first ten

days after planting, and by far the most of it within the first five

days. During this time the moles enter the field by burrows branch-

ing off from their permanent runs along the hedges or in the ad-

joining uncultivated fields, and spread out among the newly planted

corn rows. These runs in the freshly planted field tend to follow

the rows of corn in the direction in which the planter was driven, and

not along the rows checked off by the chain. Tunnels entering at

right angles to the direction of planting soon turn and follow that

direction. Approximately 75 per cent, of the burrows made during

the first few days after ])lanting were directly in the furrow made by

the planter. The remaining 25 per cent, were divided about equally

between two courses, those parallel to the rows but not entering them,

and those making various angles with them.

As an illustration of the extent and nature of the damage done,

tlie following rather extreme case may be given. Three adjoining

rows, the farthest within thirty feet of the edge of the field, had been

entered from tiiat side. In the first row the line of hills had been

followed for one hundred and twenty feet, and there were only three

or four liills uninjured within that distance. In the second row all

hills iiad l)een taken for thirty feet, and in the third row all were miss-

ing for seventv-five feet. These l)urrows following- the rows and



11

those connecting them with the edge of the field were nearly all the

burrows in that immediate locality. Wherever a burrow passed

through a hill, the corn was missing. The three or four hills still

growing in the one hundred and twenty-foot distance mentioned

above, had been missed by the burrows, which passed around and not

through them. This corn had been planted about a week. In an ad-

joining field planted twelve days before, there were also extensive

mole-runs, all made after a recent rain. Here the burrows ran irregu-

larly in all directions, no preference being shown for the direction of

the rows. No damage had been done by these freshly made burrows

in the first-planted field, though the mole had sometimes lifted young

plants bv burrowing under the hills. It is possible that if the weather

had been hot and dr}' the com in these hills might have withered.

Farmers, indeed, maintain that this is sometimes the case. This ob-

servation of the work of moles in corn fields was continued through-

out the season in various parts of the state until December. In mid-

summer the moles burrowed to a depth of about six inches, but did

not tend to follow the rows, nor was any injury done to the corn

except possibly a trifling one due to undermining the plants. Peas

and beans planted by drills in gardens were sometimes injured in the

same way as corn in the field, but here too the injury was done dur-

ing the first week after planting, and the later burrows did not tend

to follow the direction of the drills.

On visiting a badly infested corn field it is easy to understand how
an uncritical observer might attribute to the mole a deliberate malice

and a cumiing almost human in finding and destroying the newly

planted corn, but probably a simpler explanation of the facts may be

given. In soft ground the nms of the mole are often carried for long

distances in a straight line. I have seen such runs several hundred

feet long in the sandy fields of Mason county. Probably the course of

the drill of the planter is followed because it offers the line of least

resistance immediately after planting. Later, when the ground be-

comes settled, so that all parts of the soil are ec[ually finn, there is no

apparent choice in the direction of the runs.

It has been suggested in defense of the mole that grubs or other

insects may destroy the gemiinating corn, and that the mole visits the

hills to capture the insects. If this be so, the mole is certainly a

marvelously effective agent for the destruction of insects, for often

not a hill of corn will be missing out of many acres except where



12

there is a mole-run. It lias been also said that field-mice may enter

the runways of the mole, and that they and not the moles may eat

the seed grain. P'ield-mice doubtless make use of old mole-runs, but

would scarcely enter such a run while its owner was still present;

and as the seed is eaten and the plants are destroyed at the time when

the burrows are dug', the injury cannot be attributed to anything else

than the mole.

Moles are accused not only of destroying recently planted seed,

but also of eating the roots or tubers of garden vegetables. Late in

the season of 1907 I visited a field at White Heath, in which it was

said that much damage had been done by moles. The potatoes had

been dug just before m)' arrival but partly eaten tubers were abun-

dant, all near the edge of the field, and next to woodland and pasture.

The moles had tunneled extensively among the potato hills, and many
of the potatoes had been eaten by them, as appeared plainly from the

marks of incisor teeth, which just fitted the teeth of the mole, but

were much too broad to be the work of the mice or voles found in

the vicinity. Chipmunks and gophers were in the adjoining fields,

but of course would have taken the potatoes, if at all, by digging

down into the hills and not by an underground tunnel. The loss in

parts of the field was some 25 per cent. During the past season the

same field was planted to potatoes again. I visited it in September,

before the potatoes were harvested. Mole-runs were numerous in the

field, running among the rows in all directions, but in no definite re-

lation to the hills. Tubers had often been laid bare by the moles but

they were generally uninjured. A few had been eaten by grubs, but

only one by a mammal. Evidently the moles, while not searching for

vegetable food, do sometimes avail themeslves of it when it is pres-

ent. Usually their tunnels are so placed that little vegetable matter

is encountered in making them—too small an amount to supply any

considerable part of the energy expended by this powerful and active

animal. The injuiy done by moles to lawns and other grass-lands is

undoubtedly done in their search for insects and wonns. It is not,

indeed, great except in small lawns, cemetery lots, and the like, the

appearance of which they may injure sufficiently to call for their de-

struction.

But little is known definitely in regard to the enemies of moles.

Cats and dogs kill but do not eat them. Weasels, skunks, and foxes

probably kill them occasionally and, when hard pressed for food, may



13

eat them. In Dr. Fisher's study of the contents of 2645 stomachs of

birds of prey, moles were found only four or five times. ("Hawks
and Owls of the United States".) There seems to l)e a considerable

local variation in the numljers of moles from year to year, and they

are often found lying dead, but unmutilated, above ground in con-

siderable numl^ers. Many of them are badly infested with intestinal

parasites, which possibly tend to reduce their numbers. Two such

parasites, specimens of Filaria and Spiroptera, were abundant in the

stomach and intestines of many of the moles collected by us for a

study of their food.

My own attempts to poison moles have had uncertain success, as

it was difficult to tell, even appro.ximately, the number killed. They

eat bits of raw beef readily in captivity, and might be poisoned by

putting strychnine on bits of meat and placing these in their runs. I

have found trapping the best way to destroy them. A single mole

will do a surprising amount of burrowing in a week, and the number

of moles doing noticeable damage in any locality is generally not

large. It is difficult to trap them in midsummer, when they frecpient

only their deeper burrows, but easy in spring or autumn, when they

work near the surface. There are a number of good mole-traps on

the market, all made with reference to the mole's habit of persistently

repairing a burrow if its roof is broken in. Where the work of the

mole is evidently recent, a virtual extermination by trapping is neither

difficult nor tedious. Even in places where they have been long es-

tablished, and where the ground may not be plowed up, persistent

work during the spring months will accomplish much. Where there

is an intricate network of old runs it is very difficult to trap them;

yet even here occupied runs may sometimes be detected. If the trap

is undisturbed for twenty-four hours it may be safely inferred that

it has been placed on an aljandoned nuiway, and another trial must

be made elsewhere. During the season of 1908 experiments were

made by treating seed-corn with kerosene, carbolic acid, fomialin, oil

of lemon, and other vegetal)le oils, to see whether moles would be so

repelled by these substances that they would not disturb the corn.

No definite results were obtained, however, except where an amount
of repellent was used sufficient to injure the seed.

October, IQIO.