Michigan, Ohio, Pennsylvania east to Dauphin County and south in
the mountains to northwestern North Carolina. See figure 28 on
page 180.
_Characters for ready recognition._--Distinguished from _M. r.
rixosa_ by three average differences, namely, darker color,
shorter tympanic bullae, and smaller size of males; from _M. r.
campestris_ in smaller size: hind foot less than 25 in males and
less than 22 in females; in males total length less than 216 and
tail averaging less than 34, color averaging darker; from _M.
frenata_ and _M. erminea_ of same region by basilar length less
than 31, tail less than 45, and lacking black pencil.
_Description._--_Size._--Male: An adult or subadult from Fair
Oaks, Pa., a subadult from Finleyville, Pa., and an adult from
Huttonsville, W. Va., measure, respectively as follows: Total
length, 206, 194, 191 (average 197); length of tail, 37, 32, 28
(32); length of hind foot, 23 in each. An adult from Roanoke,
Indiana, weighs 40.6 grams.
Female: Two young from Leasuresville, Pa., and Middle Paxton
Twp., Pa., measure, respectively, as follows: Total length, 188,
172; length of tail, 33, 30; length of hind foot, 20.5, 21. An
adult from Monroeville, Ohio, weighs 40.5 grams and a young
individual from Middle Paxton Twp., Pa., 39.3 grams, and a
subadult from Swan Creek Exp. Station, Allegan Co., Mich., weighs
49 grams.
_Color._--Winter pelage either all white, or brown as in summer;
upper parts about Raw Umber, or tone 2 of Carbo Brown of pl. 342
of Oberthür and Dauthenay. Underparts white at least on thoracic
region; approximately three-fourths of specimens with brown rictal
spot at angle of mouth or with this area covered by brown upper
parts which extend down on each side and meet on the underparts in
about one specimen out of three; upper lips and hind feet
ordinarily brown; toes of forefeet ordinarily white (see under
remarks for details of color pattern). Least width of color of
underparts in the specimens in which the dark color of the upper
parts does not encircle the body averages 60 per cent of greatest
width of color of upper parts, or including all specimens the
percentage is 42.
_Skull_ (based on specimens from Pa. listed in table of cranial
measurements, which see and plates 14 and 15).--Basilar length
29.7 and 28.6 in male and 28.0 in female; weights unavailable;
otherwise as described in _M. e. richardsonii_. The length of the
tympanic bullae seems to be actually less, and less in relation to
the basilar length, than in other American subspecies of _M.
rixosa_.
_Remarks._--Robert Kennicott's mention in 1859 (p. 245) of what seems
to be this subspecies is the earliest reference to it that I can
identify in the literature. He used the specific name _pusillus_ and it
was not until 1900 that Samuel N. Rhoads proposed the name _Putorius
allegheniensis_. Since 1900, several records of occurrence have been
published which have made the geographic range of this race better
known.
An adequate number of specimens has been gathered only from Ohio and
from western Pennsylvania. Many from Ohio are without accurate external
measurements taken in the flesh. The majority of the specimens from
Pennsylvania owe their preservation to the willingness of local
officials, who pay bounties on weasels, to save the skins of _Mustela
rixosa_. These specimens ordinarily comprise the skin with locality but
because the feet, external measurements in the flesh, and skulls are
unavailable, the material is far from adequate and to give an accurate
notion of the usual or average cranial characters of _allegheniensis_
in Pennsylvania, skulls from there are especially desirable.
A smaller percentage of the specimens from Ohio than from Pennsylvania
have the brown color of the upper parts meeting on the underparts.
Also, more of the specimens from Ohio are lighter colored and this
suggests intergradation with the subspecies _campestris_ and _rixosa_
to the westward.
From Pennsylvania 23 animals in brown pelage are available. In 5 there
is a rictal spot at the angle of the mouth; in 5 the area is white and
in 13 the brown color of the upper parts is continuous over the area in
question. Only 2 of 23 have the upper lips white. Eight have the color
of the upper parts meeting on the venter thus restricting the white of
the underparts to the chin, throat, and pectoral region, and 6 of these
have a white area in the inguinal region as well. The toes of the
forefeet are white in 3 of 4 animals suitable for examination in this
regard and the hind feet are marked with white in 3 of the 8 animals
which have the hind feet preserved. _Mustela rixosa_ in Pennsylvania
parallels the species _Mustela frenata_ in that in this relatively
humid area of the northeastern United States the color of the upper
parts is darker and the area of the dark-colored upper parts is
increased at the expense of the area of the light-colored underparts.
Also _Mustela erminea_ in this same region (range of the subspecies
_Mustela cicognanii_) shows the same tendency to darker color of upper
parts and their extension in area at the expense of the area of the
light-colored underparts, or was mentioned above.
It is difficult to account for the seeming absence of the species from
New England and all that part of Canada and the United States south of
the St. Lawrence River and northeastward from Pennsylvania. The size of
females of _M. erminea cicognanii_ in that territory is so little more
than in _rixosa_ that the latter possibly cannot successfully compete
with the _erminea_ stock which may already occupy the ecologic niche to
which _rixosa_ is adapted. It will be remembered that in western North
America in territory seemingly climatically suitable for _rixosa_ it
occurs no farther southward than the line below which _M. erminea_ has
become reduced to a size comparable with that of _M. rixosa_.
Of 41 subadult and adult skulls assigned to this subspecies 24 have
obvious lesions in the frontal sinuses evidently resulting from
infestation by nematodes. More in detail, none of the specimens from
Illinois (3 individuals), Pennsylvania (3 barely subadult), or West
Virginia (2) displays lesions. From Wisconsin, Indiana, Virginia and
North Carolina there is one specimen each and each specimen displays
lesions. From Ohio, 17 of 23 specimens display lesions. From Michigan 3
of 8 specimens display lesions; 2 adults and one subadult have lesions
and 5 subadults do not have lesions.
_Specimens examined._--Total number, 102 as follows: Arranged
alphabetically by states and within each state by counties from
north to south. Unless otherwise indicated, specimens are in the
United States National Museum.
=Indiana.= _Huntington County_: Roanoke, 1. _Wells County_:
Harrison Township, 1[76].
=Illinois.= _Lake County_: Deerfield, 3[60]; no locality more
definite than county, 1[60] _Cook County_: Northfield, 1[60]; La
Grange, 1[18].
=Michigan.= _Tuscola County_: 8 mi. N Caro, 1[76]. _Santilac
County_: Deckerville, 1[76]. _Allegan County_: Swan Creek Exp.
Station, 1[76]; Swan Creek Farm, 1[76]; T. 2N, R. 14W, 1[76];
Allegan, 1[76]. _Livingston County_: George Reserve, 1[76]; 1/2
mi. N Unadilla, 1. _Oakland County_: Rochester, 1[76]. _Macomb
County_: Romeo, 1[76]. _Washtenaw County_: 5 mi. SW Ann Arbor,
1[76]. _Branch County_: vic. Coldwater, 1[76].
=North Carolina.= "near Marshall," 1.
=Ohio.= Northern part of state, 1[81]. _Williams County_: Stryker,
1[60]. _Lucas County_: Monclova, 1[60]. _Erie County_: Sandusky,
2[76]; marsh near Sandusky, 1[76]; Berlin Heights, 1[76]; no
locality more definite than county, 1[2]. _Wood County_: 10 mi. NE
Bowling Green, 1[76]; Bowling Green, 4[76]; 3 mi. E Bowling Green
1[76]; Plain Township, 1[2]; Portage Township, 1[60]. _Loraine
County_: Wellington, 1[81]. _Huron County_: west of Monroeville,
1[76]. _Summit County_: Ira, 3[81]. _Portage County_: Suffield,
1[81]. _Hancock County_: Vanburen, 1[76]; Findlay, 1[81]; 9 mi. S
Findlay, 1[76]; no locality more definite than county, 7 (2[76],
2[81], 3[2]). _Mahoning County_: Ellsworth, 1. _Crawford County_:
"near Crestline," 1[81]. _Delaware County_: Sunbury, 1[2]; Lewis
Center, 1[81]; no locality more definite than county, 1[81].
_Licking County_: Johnstown, 1[2]. _Fairfield County_: Baltimore,
1[81]; Violet Township, 1[81]. _Meigs [= Gallia?] County_: Vinton,
1[81].
=Pennsylvania.= _Erie County_: McKeen Twp. 1. _Crawford County_:
Springboro, 1[1]; Pymatuning Swamp, between Hartstown and
Shermansville, Sadsbury Twp., 3[9]. _Mercer County_: Shenango
Twp., 1. _Lawrence County_: Little Beaver Twp., 1. _Butler
County_: Leasuresville, 1[9]; Clearfield Twp., 1; Valencia, 1[9].
_Armstrong County_: Ford City, Burrell Twp., 1. _Indiana County_:
Smicksburg, 1; N. Mahoning Twp., 2; White Twp., 1. _Allegheny
County_: South Hills, Pittsburgh, 1[9]; "near Pittsburgh," 1[9];
Fair Oaks, 1[9]. _Westmoreland County_: Bolivar, 1. _Dauphin
County_: Middle Paxton Twp., 1. _Washington County_: Finleyville,
1; Rea, 5; Beallsville, 1[1]; Claysville, 1. _Green County_: Deep
Valley, 1; Waynesburg, 1; Jefferson, 1; Cumberland Twp., 1.
_Fayette County_: Acme, 1[9]; _Somerset County_, 1. _Lancaster
County_, 1.
=West Virginia.= _Randolph County_: Huttonsville, 1.
=Wisconsin.= _Sauk County_: Sumpter Twp., 1[60]. _Dodge County_:
Beaver Dam, 1[50]. _Dane County_: Madison, 1; McFarland (=
MacFarland), 1.
=Mustela rixosa campestris= Jackson
Least Weasel
Plates 14 and 15
_Mustela campestris_ Jackson, Proc. Biol. Soc. Washington, 26:124,
May 21, 1913.
_Putorius pusillus_, Aughey, Sketches of the physical geography and
geology of Nebraska, p. 119, 1880, Omaha.
_Mustela rixosa campestris_, Swenk, Journ. Mamm., 7:329, Nov. 23,
1926.
_Type._--Female, adult, skin and skull; no. 171490, U. S. Nat.
Mus., Biol. Surv. Coll.; Beemer, Cuming County, Nebraska; April
18, 1911; obtained by G. Sharp; x catalogue no. 8440.
The skull is unbroken. On the left side, C1 and P2 are missing;
the other teeth are present and entire. The skin is excellently
made and in a good state of preservation.
_Range._--South Dakota, Nebraska and Iowa. See figure 28 on page
180.
_Characters for ready recognition._--Differs from _M. r. rixosa_
and _M. r. allegheniensis_ in larger size: Hind foot more than 25
in males and ordinarily more than 22 in females; in males total
length more than 216 and tail averaging more than 34; color
possibly slightly paler than in _M. r. rixosa_ and averaging paler
than in _M. r. allegheniensis_; from _M. frenata_ and _M. erminea_
of the same region by basilar length less than 32; tail less than
50, and lacking black pencil.
_Description._--_Size._--Male: Four adults from Nebraska yield
average and extreme measurements as follows: Total length, 231
(225-237); length of tail, 36 (32-39); length of hind foot, 29
(28-31).
Female: Six adults from Nebraska yield average and extreme
measurements as follows: Total length, 192 (184-225); length of
tail, 35 (28-40); length of hind foot, 23 (20.5-26).
_Color._--Winter pelage ordinarily white; as described in _M. r.
eskimo_ except possibly paler and certainly with line of
demarcation on side of head between upper parts and underparts
passing almost straight back without the dorsally directed
reëntrant angles of white behind the eye and ear; least width of
color of underparts in four specimens from Nebraska averaging 80
(49-89) per cent of greatest width of color of upper parts, but in
a fifth animal in summer pelage the brown color of the upper parts
encircles the body.
_Skull._--See measurements in table and plate 15; weight 1.1 grams
(male from Brown Co., S. D.); basilar length, 30.7 in male from
Clay Co., Neb., and 28.8 in female from same county; otherwise as
described in _M. e. richardsonii_.
_Remarks._--In his revisionary treatment of the American races of
_Mustela rixosa_, Myron H. Swenk (1926:313) credits Samuel Aughey with
recording this animal, _M. r. campestris_, from Nebraska, as early as
1880, under the name _Putorius pusillus_. In 1908, Swenk recorded the
animal from the same state under the name _rixosus_ and in 1913 the
race _campestris_ was formally named by H. H. T. Jackson.
On the testimony of a friend who had previously obtained several
specimens for him, Swenk (1926:321) records the least weasel from
Oshkosh, Garden County, Nebraska, which is a marginal record of
occurrence to the southwest for _M. r. campestris_.
At an early stage in the study of American weasels the writer examined
the specimens from Nebraska saved by Mr. Myron H. Swenk and recorded
measurements of them. However, at the time of writing this account the
specimens were not available for examination and the account of
coloration is accordingly incomplete.
The large size, particularly the large external measurements, comprises
the principal distinguishing character of this subspecies of the least
weasel.
Of the four adults examined from Iowa and South Dakota one exhibits
lesions such as result from infestation of the frontal sinuses by
nematodes.
_Specimens examined._--Total number, 21 as follows. Arranged
alphabetically by states and by counties, from north to south in
each state. Unless otherwise indicated, specimens are in the
United States National Museum.
=Iowa.= _Howard County_: Chester, 1[12]. _Palo Alto County_:
Emmetsburg, 1[65]. _Kassuth County_; Algona, 1[65]. _Clayton
County_: National, 1. _Storey County_: Nevada, 1[65]. _Wapello
County_: Ottumwa, 1[65]. _Henry County_: Mount Pleasant, 1[66].
=Nebraska.= _Holt County_: Page, 1[35]. _Madison County_: Norfolk
1[35]. _Cuming County_: Beemer, 1. _Hamilton County_: Chapman,
1[35]. _Clay County_: Inland to 1 mi. east thereof, 7[35].
=South Dakota.= _Brown County_: shore of Sand Lake, S. 15 T. 126N,
R. 62W, 1. _Day County_: Waubay Migratory Waterfowl Refuge, 1.
_McCook County_: Salem, 1[102].
=MUSTELA FRENATA= Lichtenstein
Long-tailed Weasel
(Synonymy under subspecies)
_Type._--_Mustela frenata_ Lichtenstein, Darstellung neuer oder
wenig bekannter Säugethiere, pl. 42 and corresponding text
unpaged. 1832.
_Range._--From southern Canada southward over all of the United
States, México, Central America, Venezuela, and the republics of
western South America to southern Perú and extreme northern
Bolivia. All the life-zones from Alpine Arctic to Tropical are
inhabited. In the extremely desert region of southeastern
California and western Arizona the species is scarce or possibly
absent although recovery of a skull (see under account of _M. f.
neomexicana_) from near the center of this region at Potholes on
the Colorado River, and a reported occurrence in the mountains of
Baja California, México, indicate that a few individuals of the
species live in favorable habitat even in this desert region.
_Characters for ready recognition._--Differs from _Mustela erminea_, in
regions where the two species occur together, by tail more than 44 per
cent of length of head and body and by postglenoidal length of skull
less than 46 per cent of condylobasal length in males and less than 48
per cent in females (see under characters of the species); from
_Mustela rixosa_ by presence of black pencil on tail, caudal vertebrae
more than a fourth (2/5-3/4) of length of head and body, basilar length
of skull more than 34 mm.; from _Mustela africana_ by absence of thenar
pad on forefoot, underparts without longitudinal, median, abdominal
stripe of same color as upper parts, upper lips narrowly (rather than
broadly) edged with color of underparts, longest facial vibrissae
extending to or behind posterior margin of ear; presence of p2; more
inflated (see pls. 23 and 30) tympanic bullae.
_Characters of the species._--Size large: Total length 300 to 550 mm.;
tail two-fifths to seven-tenths of length of head and body, with
distinct black pencil at end; caudal vertebrae 19 to 23; skull with
long precranial portion; postglenoidal length, expressed as a
percentage of the condylobasal length, less than 47 in females and
ordinarily less than 46 in males; upper parts brown; light-colored
underparts, in summer pelage, tinged with buffy or yellowish and
continuous from chin to inguinal region; some subspecies (southwestern
United States, México, Central America, and Florida) with white or
yellowish facial markings which do not occur in any other American
species of the genus _Mustela_.
_Geographic variation._--Forty-two subspecies are recognized, and the
species is geographically more variable than any of the other 3
American species. Color, color-pattern especially on the head, relative
proportions of the tail, hind feet, body including the head, and shape
and size of the skull are the principal features in which geographic
variation has been noted. The variation in the skull extends to the
basicranial region (shape and size of tympanic bullae and related
structures), interorbital region and preorbital region.
_Natural History._--Habitat and Numbers.--As has already been remarked,
the long-tailed weasel is absent from the extreme desert of the
southwestern United States and northwestern México. Possibly the
absence of water to drink is the limiting factor. In southern Nevada
the finding of weasels only in places that were well watered, even
though small rodents suitable as food for weasels were even more
abundant in the surrounding desert, supports this possibility that the
absence of water to drink is the limiting factor. Also at Berkeley,
California, in early December of 1927 in the canyon at the head of
Dwight Way and in the autumn and winter of 1928 in Strawberry Canyon on
the campus of the University of California, I trapped extensively for
this species in different habitats and obtained, in all, four
individuals no one of which was farther than 10 feet from water. The
lesser cruising range of the individual weasel than of, say, the
coyote, probably explains why, in an arid region, for example
Pahranagat Valley, Nevada, only the meadow mice and their riparian
associates are preyed upon by the long-tailed weasel whereas the coyote
preys upon these riparian rodents and also upon the kangaroo rats and
other rodents which are so abundant in adjoining habitats that are
devoid of water.
In areas where water is available every few hundred yards, no
particular habitat seems to be avoided in summer providing there is
food for the long-tailed weasel. In winter (January and March) there
obviously was a choice of habitat, possibly occasioned by more abundant
food or more satisfactory shelter, or both, in Centre County,
Pennsylvania, where Glover (1943B) found the population density in the
chestnut-oak habitat to be one weasel per 6.5 acres in areas of tree
cuttings and slash and one weasel per 13.3 acres in the open forest. In
the scrub oak-pitch pine forest type the population was one weasel per
26.4 acres in tree cuttings and slash and one weasel per 38.2 acres in
the open forest. No weasel was found in an area of 9.6 acres comprising
a wood lot, the edge of the forest, abandoned fence rows and an
abandoned orchard. The two types of forest in which he did find
weasels, 25 in all, comprised 381.6 acres. Glover's (_op. cit._) data
is the only precise information known to me on actual numbers of
long-tailed weasels in a given area of any considerable size.
Fluctuations which I elsewhere (1946:57) have designated as multiannual
fluctuations occur in this species but seemingly not in the degree that
they do in _Mustela erminea_. This difference between the two species
is to be expected because _M. frenata_ does not range so far northward
toward the polar regions as does _M. erminea_ and populations of most
kinds of animals in the polar, at least in the arctic, regions are
subject to more extreme and more regular fluctuations than are kinds of
animals in temperate or tropical regions. Indication of the means by
which decrease in the weasel population is brought about is afforded by
Osgood's (1935:156) observations around Rutland, Vermont. In the late
winter of 1934, tracks indicated that weasels left their usual haunts
and hunted cross lots, vainly trying to find food. Testing of the small
mammal population in the spring and summer of 1934 showed that it was
at low ebb. In the fall of 1934 mice and shrews were abundant again but
weasels seemed to be entirely absent. The decrease in the population of
weasels lagged behind the decrease in the population of the herbivorous
prey as did the subsequent increase; this, of course, is the normal
relation of carnivorous species of mammals and their prey, at least in
and above the Transition Life-zone.
The average distance away from the central den which four weasels (sex
unspecified) traveled in a single night at Ames, Iowa, was 312 feet;
the maximum distance was 642 feet. These data were obtained in the
winter of 1939 by Polderboer, Kuhn and Hendrickson (1941:115) who
studied the tracks in the snow. In Manitoba, Criddle and Criddle
(1925:143) noted that a female which lived in their basement often
wandered more than half a mile away in search of food. In Michigan,
Quick (1944:75) found the maximum distance traveled in one day (=
night?) by a large male to be 3.43 miles although two miles was the
average distance traveled by this individual. In 1942, from January 4
to March 4, in Centre County, Pennsylvania, Glover (1943B) studied
tracks of 11 males and 10 females, in newly fallen snow, and
ascertained that the distance traveled in a single night averaged 704
(60-2535) feet for the male and 346 (20-1420) feet for the female. The
weasels in the open timber traveled farther per trip than those in the
brushland and dense stands of trees.
Behavior
An adult female (now the holotype of _Mustela frenata nevadensis_) seen
running across a field, and, I think, unaware of my presence, at every
bound bent her back up so far that she reminded me of a measuring worm.
For part of the time when running, the tail was held off the ground
straight out behind, and then, for a while, inclined upward at an angle
of about 45°. Another weasel that I saw in the daytime, and that I
think was unaware of my presence, was bounding along among the
_Baccharis_ bushes on the south-facing slope of Dwight Way Canyon,
Berkeley, California. This individual, at each bound, arched the back
up so high as to remind me, again, of a measuring worm.
The long-tailed weasel is a land mammal and unlike its close relative,
the mink, is seldom seen in the water. That it can swim, however, is
attested by the capture of one while it was swimming across the Río
Ramos in México (Davis, 1944:381). Also, Green (1936), in May, in
Gratiot County, Michigan, saw a weasel, running with a _Peromyscus_ in
its mouth. The weasel dropped the mouse, entered the water and swam to
a hole among stones.