poultry killer. In most cases apparently it is a fully-grown male that
does the killing. There are exceptions, of course, but when we see a
large weasel actively engaged in rodent hunting within a few feet of a
brood of newly hatched chickens and not even looking at them, we must
at least pause to ask if this animal is the enemy that we were taught
to believe it to be."
A suggestion that weasels sometimes obtain the prey killed by hawks is
offered by Criddle and Criddle (1925:147) who write: "Hawks are not
always the aggressors, as is shown by an incident reported by Mr. H.
L. Seamans, of Lethbridge, Alberta. Mr. Seamans noted a large buzzard
suddenly fly straight upwards from a fence post, and then alight upon
another one some distance away. A little while afterward this bird once
more arose in the same manner as before, and presently repeated the
performance again. An investigation then followed and revealed that a
Long-tailed Weasel was following the hawk from post to post.
"We should hardly expect a weasel to attempt to capture a bird of the
above type. On the other hand, it is possible that these animals might
be able to startle a hawk sufficiently to cause it to drop its prey,
which would thus provide food for the weasel."
The following frequency index is compiled from the foregoing data on
prey of _Mustela frenata_.
Moles (family _Talpidae_), 5
Shrews (family _Soricidae_), 26
Pigmy weasel (_Mustela rixosa_), 1
Ground squirrels (genus _Citellus_), 23
Chipmunks (genus _Tamias_), 38
Tree squirrel (possibly all _Tamiasciurus_), 8
Flying squirrel (genus _Glaucomys_), 1
Pocket gophers (family _Geomyidae_), 34
Mice (order _Rodentia_), 96
Harvest mice (genus _Reithrodontomys_), 36
Grasshopper mouse (genus _Onychomys_), 1
Deer mice (genus _Peromyscus_), 235
Cotton rat (genus _Sigmodon_), 2
Wood rats (genus _Neotoma_), 14
Meadow mice (genus _Microtus_), 248
Muskrat (genus _Ondatra_), 1
Old World rats (genus _Rattus_), 19
House mouse (genus _Mus_), 1
Jumping mouse (genus _Zapus_), 5
Varying hare (_Lepus americanus_), 5
Rabbits (genus _Sylvilagus_), 48
small birds, 32
chickens, 17
lizard, 1
snakes, 4
insects, 3
More significant than the above compilation, of course, are the results
of careful studies of the food of the long-tailed weasel in restricted
areas. Examples of such studies are those of Polderboer, Kuhn and
Hendrickson (1941) and Hamilton (1933:333).
According to Hamilton's (1933:332) observations on captive weasels,
"There seems to be little relative difference in the amount they eat,
regardless of their activities.
"In general, more food is taken in summer than in winter. Usually about
a third their weight every 24 hours is eaten, but a growing young
weasel will consume much more. A young male _noveboracensis_, weighing
145 grams, consumed an entire chipmunk, fur and bones, weighing 85
grams, in 24 hours. A day later it ate all of a partly grown rat, 105
grams, in the same length of time."
Moore (1945:253) records that a captive male that he obtained at
Gainesville, Florida, consumed, on the average, between 63 and 70 grams
of flesh and blood per day. The weasel itself weighed approximately 320
grams.
Sanderson (1949:413), concerning seven young weasels from Manitoba,
that he raised in captivity, writes: "From the fifth to the seventh
week of age, they consumed approximately 22 per cent of their body
weight per day; from the eighth to the tenth week (just before reaching
mature size) they consumed approximately 24 per cent; but after
reaching maturity they consumed only 18 per cent. When given all the
food they would take in one day, they ate as much as 40 per cent of
their body weight."
Criddle and Criddle (1925:143, 146) say that weasels drinking at a bird
trough "held their mouths very close to the water and as far as we
could see, lapped the liquid up with rapid movements of the tongue. As
a rule, after drinking, they would merely spring to the ground and
vanish amid a bunch of scolding birds, but occasionally we have seen an
animal slowly drag itself through the water and follow this performance
by some rapid gambols, or a quick run, a method of drying which most of
us have practiced in our youth." According to Hamilton's (1933:332)
observations on captives, "Weasels are great drinkers, and while they
take but little at a time, about 25 c.c. is drunk by a large animal
during a day. . . ."
Reproduction
Philip L. Wright's several papers (1942A, 1942B, 1947, 1948A, and
1948B) reporting on his detailed studies of _Mustela frenata_
(subspecies _oribasus_ and _longicauda_) in captivity have yielded a
large share of the precise information that we have concerning breeding
and reproduction in this species. He has found that a single litter, of
up to 9 young is born in the spring, usually in April. At three months
of age the females "are full grown." The young males remain sexually
immature during the first summer but the young females, as well as the
females which are more than a year old, come into heat in the midsummer
and are bred by the adult males. After a long period of quiescence
lasting for several months, the embryos resulting from these matings
become active in early spring and develop to full term in less than 27
days after they become implanted. The adult males are sexually active
from April into August, when the testes are at maximal size and are
conspicuous in the scrotum. A gradual regression takes place starting
in August and extending into September. By October the testes may be
fully regressed and the molt to white may start in this month. The
white winter weasel, of either sex, is sexually inactive. The testes of
the sexually active male in early spring and late summer are seven to
eight times the size of the fully regressed testes. Females which had
borne and suckled young were first found to be in oestrus 65 to 104
days after birth of the young. Lactation lasts for approximately 5
weeks. In 18 litters the length of the gestation period varied from 220
to 337 days with an average of 279 days. The female in heat has the
vulva much swollen and she will remain in this condition for several
weeks if not bred. Wright (1948A) describes the actual mating as
beginning with a scuffle after which the male grabs the female by the
scruff of the neck with his teeth and holds her until she becomes
subdued when he clasps her lower abdomen with his front feet and arches
his back over her posterior regions. The two animals remain locked in
this position usually for two hours and sometimes for longer than three
hours. If the animals are left together, copulation may take place
again on the same day or upon succeeding days.
Hamilton (1933:316-321) writes of a freshly born _M. f. noveboracensis_
that it ". . . was pink and much wrinkled. The wetness . . . did not
entirely obscure a few sparse, rather long, white hairs . . . over its
back and head. It had the pronounced and extraordinarily long neck of
the adult." At one day of age the average weight of six individuals in
the litter was 3.1 grams, which is 3 per cent of the weight of the
adult female and 1-1/2 per cent of the weight of an adult male. At two
weeks of age "The silky white hair . . . obscures the general flesh
color of the skin, evident a week earlier. The hair on the back of the
head and neck, also over the shoulders, is slightly longer than that of
the back . . ." but there is no crest or mane or pompadour at this or
any other age such as characterizes the juvenal ermine. When 21 days
old one young male "hurried from the nest chamber and commenced to eat
some meat." At three and a half weeks "They are all eating small pieces
of meat. . . . The canine teeth have made their appearance in both the
upper and lower jaw, but just a hint of the incisors show. Some of the
cheek teeth are through, as the meat appears to be thoroughly
masticated by the little ones." On the 36th and 37th days the eyes
opened. Sanderson (1949:415) found that a litter of seven young of
_Mustela frenata longicauda_, from Manitoba, raised in captivity,
"reached the peak of their growth" at approximately ten weeks of age.
Several nests have been found. In Manitoba, Sanderson (1949:412)
excavated a burrow at the mouth of which he had trapped the adult
female and in which he found eight young approximately five weeks old.
The "burrow was about three inches in diameter, with two chambers at a
depth of twelve inches. One of these was empty, the other contained the
young. The two surface-openings were but two feet apart and the entire
burrow was no more than three feet long. . . . The meager nest
material consisted entirely of finely chopped grass. There was no mouse
hair present, no accumulation of fecal material, and no storehouse
containing food."
Charles O. Handley has written me that on January 25, 1929, on the
Sinkola Plantation, Thomas County, Georgia, he investigated the living
quarters of a family of five weasels, four of which had been shot five
days before by a hunter. According to the hunter each of the four which
had been killed was approximately two-thirds the size of one which
escaped into a hole in the ground. Handley found that the weasels had
been using as headquarters a burrow in the trunk of an old uprooted oak
as well as a nearby gopher burrow. The burrow in the oak was
approximately ten feet long and had been excavated in the rotten wood.
In a distance of fifty feet along the gopher tunnel there were several
used openings with pathways leading away from each. On February 6,
Handley, with the help of a friend, trapped a large male weasel near
this place.
Criddle and Criddle (1925:143) describe a female which, one winter,
slept in a bag of feathers in a basement of a house occupied by one of
the authors; another weasel in winter made its headquarters in a
threshing machine. The nest of the latter "was somewhat roughly
constructed and consisted of a convenient bunch of straw and chaff
under the cylinder."
Harper (1927:303) in the Okefinokee Swamp of Georgia dislodged a weasel
from the house of a wood rat and was told of a den found in the swamp
"in the trunk of a hollow cypress tree" from which a mother weasel and
three young "about the size of mice" were obtained. "The bed contained,
I suppose, a bushel or more of rabbit hair, rat hair, and squirrel
hair. It looked like it must have been used as a den for several years,
although there was no stink that I could detect except the musk from
the old Weasel." Another female and three young approximately half
grown were found in a hollow pine log.
Between January 6 and April 12, 1940, on 640 acres of land, in
Washtenaw County, Michigan, four weasels were studied and each weasel
used only one den in this period (Quick, 1944:78). Criddle (1930:279)
remarks that _M. f. longicauda_ at Aweme, Manitoba, often makes its
temporary headquarters in the burrows of pocket gophers (_Thomomys_). A
female and three young weasels were found by Shaw (1921:167) using a
nest of a mountain beaver in the burrow of that animal. Green (1936),
in May, in Gratiot County, Michigan, saw a weasel enter a hole under a
decayed log and investigated finding four young weasels in a nest
mostly of _Microtus_ fur.
In the early part (winter and spring) of 1939, at Ames, Iowa,
Polderboer, Kuhn and Hendrickson (1941) studied four weasels living in
four separate dens on 160 acres typical of Iowa farmland and excavated
three of the dens. One den was in a weed patch in an old mole run. The
nest chamber, approximately nine inches in diameter and six inches
below the surface of the ground "was filled with grasses packed in a
layer-like formation. In the center of this mass was a nest hollow
lined with patches of mouse and shrew fur. Beneath this layer of fur
and at the sides of the nest were skins, various bones, and skulls of
partially eaten mice and shrews . . . scats [were in the nest]. . . .
At intervals, layers of clean grass had been laid over the filth of the
former bed, thus giving the nest a stratified appearance." A second
den, of a large male, was in a field of sweet clover two feet high in
the former burrow of a Franklin's ground squirrel. The nest cell, seven
inches in diameter and nine inches below the surface of the ground,
"was lined with grasses mixed with much rabbit and mouse fur. Some
scats, and bones and fur of mice and shrews were matted together in
layers at the bottom of the nest." When this den was abandoned the male
weasel occupied, for a month, another burrow, 20 rods distant, of a
Franklin ground squirrel, in the field of sweet clover. The nest cell
measured 11 by nine inches and was 11 inches below the surface of the
ground. "Two nest layers were present. The first, composed chiefly of
coarse straw and grass, had apparently been occupied at some time by a
spotted skunk. . . . On top of the skunk nest was the weasel nest
composed of fine grasses, mouse fur, and skeletal remains of mice."
Relation of the Sexes to each other and to the young
Quick (1944:75) writes that on March 28, in Michigan, he found the
tracks of a male and those of a smaller animal, supposedly a female,
meeting. The two "then led along the fence for about 18 chains and both
entered the den of the male. . . . Only the tracks of the smaller
weasel left the den on the same date. Observation on April 12 showed
that the large male still occupied the den." I am at a loss to explain
this behavior since breeding would not be expected to occur in late
March and since I suppose that the male and female do not live
together except in the breeding season. Consequently, I wonder if the
sign was wrongly read.
[Illustration: FIG. 29. Map showing the geographic ranges of the
subspecies of _Mustela frenata_ and _Mustela africana_.
1. _M. f. noveboracensis_
2. _M. f. occisor_
3. _M. f. primulina_
4. _M. f. arthuri_
5. _M. f. olivacea_
6. _M. f. peninsulae_
7. _M. f. spadix_
8. _M. f. longicauda_
9. _M. f. oribasus_
10. _M. f. alleni_
11. _M. f. arizonensis_
12. _M. f. nevadensis_
13. _M. f. effera_
14. _M. f. washingtoni_
15. _M. f. saturata_
16. _M. f. altifrontalis_
17. _M. f. oregonensis_
18. _M. f. munda_
19. _M. f. xanthogenys_
20. _M. f. nigriauris_
21. _M. f. latirostra_
22. _M. f. pulchra_
23. _M. f. inyoensis_
24. _M. f. neomexicana_
25. _M. f. texensis_
26. _M. f. frenata_
27. _M. f. leucoparia_
28. _M. f. perotae_
29. _M. f. macrophonius_
30. _M. f. goldmani_
31. _M. f. tropicalis_
32. _M. f. perda_
33. _M. f. nicaraguae_
34. _M. f. costaricensis_
35. _M. f. panamensis_
36. _M. f. meridana_
37. _M. f. affinis_
38. _M. f. aureoventris_
39. _M. f. helleri_
40. _M. f. macrura_
41. _M. f. agilis_
42. _M. f. boliviensis_
43. _M. a. africana_
44. _M. a. stolzmanni_
Hamilton (1933:328), however, writes that _M. f. noveboracensis_ is to
"be found in pairs when caring for the young. During mid-May, 1927, I
several times saw a male of this species carrying food to a den of
young ones." Green (1936), in May in Gratiot County, Michigan, remarks
that while he was uncovering and examining a nest of four young
weasels, two adults ran about excitedly and one removed a young weasel.
In instances where several nearly full-grown young have been obtained
from one den it has been my experience (Hall, 1946:191) that the only
adult trapped there was the female; no adult male was found or in the
one instance when found he was living alone in a den 200 yards away
from the den of the female and her young. Data are too few to warrant a
definite conclusion about the extent to which the male aids in rearing
the young, but I have wondered if he might not do so when the young
were less than half grown and then live alone when they were more than
half grown.
=Mustela frenata noveboracensis= (Emmons)
Long-tailed Weasel
Plates 16, 17, 18, 31, 32 and 33
_Putorius Noveboracensis_ Emmons, Quadrupeds of Massachusetts, p.
45, 1840.
_Mustela fusca_ DeKay, Zool. of New York, Pt. 1, Mammalia, p. 34,
1842.
_Putorius fuscus_ Audubon and Bachman, Journ. Acad. Nat. Sci.
Philadelphia, 8 (Pt. 2):288, 1842; Audubon and Bachman, Vivip.
quadrupeds of N. Amer., 3:234, pl. 148, 1853 (pl. 1848).
_Putorius noveboracensis_, DeKay, Zool. of New York, Pt. 1,
Mammalia, p. 34, 1842; Baird, Mamm. N. Amer., p. 166, 1858;
Merriam, N. Amer. Fauna, 11:16, pl. 4, figs. 1, 1a, 2, 2a, pl. 5,
figs. 3, 3a, text figs. 4-6, 30, June 30, 1896; Bangs, Proc.
Biol. Soc. Washington, 10:13, pl. 1, figs. 2, 2a, pl. 2, figs. 2,
2a, and pl. 3, figs. 3, 3a, February 25, 1896; Cory, Mamm.
Illinois and Wisconsin, p. 366, plates, 1912.
_Putorius erminea_, Audubon and Bachman, Vivip. quadrupeds of N.
Amer., 2:56, pl. 59, 1851.
_Putorius agilis_ Audubon and Bachman, Vivip. quadrupeds of N.
Amer., 3:184, pl. 140, 1853.
_Putorius richardsonii_, Baird, Mamm. N. Amer., p. 164, 1858
(part).
_Putorius_ (_Gale_) _erminea_, Coues, Fur-bearing animals, p. 109,
1877 (part).
_Putorius noveboracensis notius_ Bangs, Proc. New England Zool.
Club, 1:53, June 9, 1899. Type from Weaverville, Buncombe County,
North Carolina.
_Mustela noveboracensis noveboracensis_, Miller, U. S. Nat. Mus.
Bull., 79:97, December 12, 1912; Soper, Journ. Mamm., 4:251,
November 1, 1923.
_Mustela cicognanii_, Henninger, Journ. Mamm., 2:239, November 29,
1921; Seton, Lives of game animals, 2:584, 1929 (part, Ohio);
Hamilton, Amer. Midland Nat., 14:290, July, 1933 (part, Ohio);
Lyon, Amer. Midland Nat., 17:109, January, 1936 (part, Ohio).
_Mustela noveboracensis_, Jackson, Journ. Mamm., 3:15, February 8,
1922.
_Mustela frenata noveboracensis_, Hall, Carnegie Instit. Washington
Publ. 473:104, November 20, 1936; Hall, Amer. Midland Nat.,
18:304, March, 1937.
_Type._--Williamstown, Berkshire County, Massachusetts. Type
specimen not known to be in existence.
_Range._--Altitudinally, sea level to highest parts of mountains
of eastern United States; Canadian Life-zone of Ontario and Quebec
southward through eastern United States in Canadian, Transition
and Upper Austral life-zones to and including upper edge of Lower
Austral Life-zone in the Carolinas and northern parts of Georgia,
Alabama, and Mississippi; westward from the Atlantic Coast to St.
Croix and Mississippi rivers. See figure 29 on page 221.
_Characters for ready recognition._--Differs: From _M. f.
olivacea_, in males, by width of tympanic bulla which is less than
rather than more than 8.5 mm., and in adult females by total
length which is less than rather than more than 345 mm. and by
mastoid breadth which is less than rather than more than distance
between articular faces of exoccipital condyle and glenoid fossa;
from _M. f. occisor_ by a number of average differences including
smaller size, relatively shorter tail and relatively narrower
skull (see measurements); from _M. f. spadix_ by least width of
color of underparts amounting to less than 41 per cent of greatest
width of color of upper parts, absence of color of underparts on
ankles and feet, adults with hind foot less than 50 in males and
40 in females, orbitonasal length less than 15.5 in males and 13.5
in females, length of tooth-rows less than 18.0 in males and 15.7
in females, mastoid breadth less than 25.5 in males and 22.0 in
females; from _M. f. primulina_ in males by interorbital breadth
averaging more than 24 per cent of basilar length, orbitonasal
length averaging more than 34 per cent of basilar length or 64 per
cent of mastoid breadth, tympanic bullae less inflated
anteromedially, than posteromedially, and in females by
orbitonasal length amounting to more than two-thirds of mastoid
breadth, by zygomatic breadth averaging less than 21, and by
anterolateral margin of tympanic bullae not projecting below
squamosal; from _M. f. arthuri_ in males, by zygomatic breadth
more than distance between anterior palatine foramen and anterior
margin of tympanic bulla and by convex dorsal outline of skull in
longitudinal axis.
_Description.--Size._--Male and Female:
=======================================================================
| Number | | |Per cent| |
LOCALITY | of | Total | Length | of | Length of |
| specimens | length | of tail | body- | hind foot |
| averaged | | | length | |
----------+------------+-----------+-----------+--------+-------------+
| 8 ad. [M] | 415 | 146 | 54% | 46.0 |
Massa- | | (390-432) | (127-159) | | (41.0-48.0) |
chusetts +------------+-----------+-----------+--------+-------------+
| 4 ad. [F] | 311 | 104 | 50% | 33.9 |
| | (298-321) | (95-114) | | (31.5-37.0) |
----------+------------+-----------+-----------+--------+-------------+
| 10 ad. [M] | 411 | 141 | 52% | 47.1 |
Liberty | | (379-438) | (124-155) | | (43.0-51.5) |
Hill, +------------+-----------+-----------+--------+-------------+
Conn. | 6 ad. and | 318 | 105 | 49% | 33.0 |
| sad. [F] | (303-338) | (80-123) | | (31.7-36.0) |
----------+------------+-----------+-----------+--------+-------------+
| 10 ad. [M] | 407 | 130 | 47% | 46.0 |
Beaver | | (372-431) | (113-143) | | (42.0-50.0) |
Dam, +------------+-----------+-----------+--------+-------------+
Wisc. | 4 ad. [F] | 326 | 99 | 43% | 35.6 |
| | (303-338) | (86-108) | | (34.6-38.0) |
----------+------------+-----------+-----------+--------+-------------+
| 10 ad. [M] | 371 | 130 | 54% | 45.0 |
Washtenaw | | (350-405) | (115-140) | | (40.0-50.0) |
Co., +------------+-----------+-----------+--------+-------------+
Mich. | 10 ad. [F] | 306 | 97 | 46% | 34.0 |
| | (290-335) | (90-120) | | (30.0-40.0) |
----------+------------+-----------+-----------+--------+-------------+
The length of the hind foot averages more than the basal length in
males whereas the reverse is true in females. The tail, relative
to the length of the body, is longer in males than in females. The
average differences in external measurements of the two sexes in
Massachusetts, are: total length, 104; length of tail, 42; length
of hind foot, 12.1. In Michigan, where the males are smaller,
corresponding differences are only, 65, 33, and 11. Weight of 19
adult males from New York (Hamilton, 1933:294), 225 (196-267)
grams and in 13 adult females, 102 (72-126) grams. Weights of 2
adults from Michigan are: [M] 258; [F] 101 grams.
_Externals._--Longest facial vibrissae black, brown, or white
(often all three colors in same specimen) and extending beyond
ear; carpal vibrissae same color as underparts and extending to
apical pad of fifth digit; hairiness of foot-soles as shown in
figure 19.
_Color._--Upper parts, in summer, Vandyke Brown or darker than
tone 4 of Burnt Umber of Oberthür and Dauthenay, pl. 304.
Sometimes approaching tone 2 of Warm Sepia of Oberthür and
Dauthenay, pl. 305. Underparts, in summer, ranging from white
through Napthalene Yellow (Peterboro, N. Y.), Pale Orange Yellow
(eastern Mass.), near Primuline Yellow (unusual specimen from
Leelanau Co., Mich.) to near (_c_) Deep Chrome (no. 19053, U. S.
Nat. Mus., Roan Mts., N. C). In winter, all white except tip of
tail, or upper parts near (12" 1) Rood's Brown and tone 2 of Raw
Umber of Oberthür and Dauthenay, pl. 301, with underparts white or
sometimes tinged with yellowish. Tip of tail at all times black.
Upper parts of uniform color except for occasional slight
darkening of nose. Color of underparts extends distally on
posterior sides of forelegs to foot and sometimes over upper sides
of toes and on medial sides of hind limbs only to knees. Least
width of color of underparts averaging, in a series of twenty-two
males, mostly in full winter pelage, from Liberty Hill,
Connecticut, 21 (11-40) per cent of greatest width of color of
underparts. In eleven females from the same place, corresponding
percentages are 20 (14-29). Black tip of tail in same series of
males, most of which are in full winter pelage, 70 (60-75) mm.
long; thus longer than hind foot and averaging 50 per cent of
length of tail-vertebrae.