large, black postauricular patches and ochraceous underparts.
_Measurements._--Thirteen male and 15 female topotypes average,
respectively: total length 224, 196; length of tail 71, 57; hind
foot 31, 29; and weight 127, 104 grams.
_Distribution._--Restricted to the area about Steilacoom and
Tacoma, Pierce County, Washington.
=Thomomys talpoides pugetensis= Dalquest and Scheffer
_Thomomys talpoides pugetensis_ Dalquest and Scheffer, Proc. Biol.
Soc. Washington, 55:96, August 13, 1942.
_Type._--Obtained 4 miles south of Olympia, Thurston County,
Washington, by W. W. Dalquest, on December 31, 1941; type in United
States National Museum.
_Racial characters._--Similar to _glacialis_ but underparts not
tinged with orange and conspicuous dusky areas present on sides of
neck.
_Measurements._--Fourteen male and 19 female topotypes average,
respectively: total length 223, 205; length of tail 62, 59; hind
foot 30, 29; and weight 123, 96 grams.
_Distribution._--Known only from the type locality.
=Thomomys talpoides tumuli= Dalquest and Scheffer
_Thomomys talpoides tumuli_ Dalquest and Scheffer, Proc. Biol. Soc.
Washington, 55:96, August 13, 1942.
_Type._--Obtained on Rocky Prairie, 7 miles north of Tenino,
Thurston County, Washington, by W. W. Dalquest on January 2, 1942;
type in United States National Museum.
_Racial characters._--Similar to _pugetensis_ but grayer, less
yellow.
_Measurements._--Eleven male and 14 female topotypes average,
respectively: total length 225, 216; length of tail 60, 64; hind
foot 31, 30; and weight 140, 118 grams.
_Distribution._--Known only from the type locality.
=Thomomys talpoides yelmensis= Merriam
_Thomomys douglasi yelmensis_ Merriam, Proc. Biol. Soc. Washington,
13:21, January 31, 1899.
_Thomomys douglasii yelmensis_ Taylor, Proc. Biol. Soc.
Washington, 32:169, September 30, 1919.
_Thomomys talpoides yelmensis_ Goldman, Jour. Mamm., 20:235, May
15, 1939.
_Type._--Obtained at Tenino, Thurston County, Washington, by C. P.
Streator on October 24, 1891; type in United States National
Museum.
_Racial characters._--A rather small, yellowish race with whitish
underparts.
_Measurements._--Twenty-one male and 21 female topotypes average,
respectively; total length 213, 202; length of tail 64, 61; hind
foot 29, 28; and weight 121, 101 grams.
_Distribution._--Known only from Grand Mound Prairie (type
locality), Vail Prairie, near Vail, and Rochester Prairie, near
Rochester, all in Thurston County.
=Thomomys talpoides couchi= Goldman
_Thomomys talpoides couchi_ Goldman, Jour. Mamm., 20:243, May 15,
1939.
_Type._--Obtained on Scotts Prairie, 4 miles north of Shelton,
Mason County, Washington, by L. K. Couch, on June 27, 1922; type in
United States National Museum.
_Racial characters._--A small race; rich hazel in color.
_Measurements._--Thirteen male and 9 female topotypes average,
respectively: total length 196, 191; length of tail 55, 53; hind
foot 27, 27; and weight 87, 79 grams.
_Distribution._--Known only from the type locality and from Lost
Lake Prairie, near Satsop, Mason County.
=Thomomys talpoides melanops= Merriam
_Thomomys melanops_ Merriam, Proc. Biol. Soc. Washington, 13:21,
January 31, 1899.
_Thomomys douglasi melanops_ Bailey, N. Amer. Fauna, 39:119,
November 15, 1915.
_Thomomys talpoides melanops_ Goldman, Jour. Mamm., 20:235, May
15, 1939.
_Type._--Obtained at head of Sol Duc River, Clallam County,
Washington, by V. Bailey on August 28, 1897; type in United States
National Museum.
_Racial characters._--Most like _shawi_ but smaller, with larger
postauricular patches and dusky areas on side of head.
_Measurements._--A male topotype measures: total length 211;
length of tail 67; hind foot 28.
_Distribution._--Higher Olympic Mountains.
=Castor canadensis= Kuhl
Beaver
_Description._--The beaver is the largest rodent occurring in
Washington. Large individuals weight approximately 50 pounds. They are
heavily-built, robust animals with large heads and short necks. The
large, flat, naked tail immediately separates them from all other
mammals occurring in the state. The forelegs are short and the forefeet
handlike. The hind legs are long, thick and powerful. The hind feet are
large and webbed for swimming. The ears are small and the eyes, although
of moderate size, are not prominent. The incisors are large and
prominent with a distinct yellow or orange color. The close, dense
underfur is overlaid with long, lax, rather stiff overfur or guardhairs.
[Illustration: FIG. 99. Beaver (_Castor canadensis_). Silvana,
Washington, August 15, 1921. (Fish and Wildlife Service by Leo K.
Couch, No. B-21912.)]
Beavers are found in Europe, Asia and North America. In America they
range from Alaska to Mexico and from the Atlantic to the Pacific. Many
American subspecies have been described, all thought to belong to a
single species.
Beavers live in streams and lakes of Washington under diverse climatic
conditions. They are perhaps most abundant in the western Washington
lowlands where there are numerous watercourses. In the Cascade
Mountains they are found well up into the Canadian Life-zone, where the
streams are swift and clear with stony bottoms. The highest altitudinal
record known to us is Reflection Lake, Mt. Rainier, 4,861 feet
(Brockman, 1939: 71). Farther east, in the timbered regions of the
eastern Cascades and in northeastern Washington, beavers live in deeper,
more sluggish streams. Abundant beaver signs were noted at the junction
of the Snake and Columbia rivers where the animals were occupying one of
the hottest, most desertlike portions of the state. They are found in
Moses Lake, in the center of the arid Columbian Plateau. Beavers once
occurred in the San Juan Islands and have recently been reintroduced
there.
[Illustration: FIG. 100. Beaver (_Castor canadensis_): lodge and
beaver pond, Elbe, Washington, August 24, 1926. (T. H. Scheffer
photo.)]
The part the beaver played in man's exploration of the state of
Washington is a story in itself. The establishment of Fort Vancouver and
Fort Spokane and other settlements was principally due to the trade in
beaver pelts. These forts served as headquarters for Douglas, Suckley,
Townsend, Nuttall and other early naturalists who contributed so greatly
to the knowledge of the mammalian fauna of the western United States.
[Illustration: FIG. 101. Cottonwood pole carved by beaver, Lake
Wenatchee, Washington, May 13, 1938. (Fish and Wildlife Service photo
by Victor B. Scheffer, No. 33.)]
Trapping for fur drastically reduced the number of beavers in
Washington. After trapping was prohibited they were slow in recovering
and, until about 1930, they were uncommon. After that date they seemed
to increase rapidly, becoming abundant about 1940. The present system of
removing beavers only from areas where they are doing damage, and then
only under strict supervision from the State Department of Game, has
held their numbers at a high level.
The food of the beaver varies greatly with locality. Along the Columbia
River, in eastern Washington, cottonwood (_Populus hastata_) and willow
(_Salix_ sp.) seem to constitute favorite foods. Few other trees grow in
this arid region. On Puget Island, near the mouth of the Columbia,
willow, alder (_Alnus oregonus_) and probably other shrubs are eaten. In
the many streams that run from the western Cascade Mountains to Puget
Sound, various species of willow seem to be the principal food eaten.
Some alder, cascara, Douglas fir, red huckleberry and salmonberry are
eaten. In some streams on the eastern slope of the Cascades, coniferous
trees, including Douglas fir, yellow pine (_Pinus ponderosa_), and red
cedar (_Thuja plicata_) are used.
Beaver dams are abundant in certain sections of Washington, notably the
area between the Cascade Mountains and Puget Sound. Dams several hundred
feet in length were seen in the valley of Cherry Creek, 7 miles
northeast of Duvall, King County. However, in most parts of the state
few dams are built. No dams are necessary in the larger streams and
lakes while the smaller mountain streams possess a gradient too steep
for successful damming. Spring floods and high water following rains
would destroy such dams.
True beaver houses, or lodges, are seldom seen in Washington. In the
larger streams, rivers and lakes the beavers are "bank beavers," living
in burrows with underwater entrances. In the mountain streams, log jams
furnish protection. Great piles of logs and debris accumulate at bends
of streams in periods of high water. These jams commonly contain large,
well-anchored key logs and persist for years. Back-cutting by the stream
often forms deep pools before the jams while the sloping bank opposite
may support willows and alders. Thus beavers may find a home, food, and
a protecting pool of deep water at a log jam. In periods of low water,
and when meandering of the stream causes it to leave the log jam, canals
are constructed by the beavers to connect the log jam with the stream.
Where dams are built a few lodges may occur. For the most part, however,
the beavers dig holes in the bank or in small islands that result from
their dam-building activities. Burrows are occasionally easy to locate
because of the mud and sticks laid on the ground above. At best these
sticks form a layer only a few inches thick and are too loosely packed
to furnish any additional protection. They probably represent a
concession to the beavers' lodge-building instincts.
The beaver probably breeds in January. A specimen from Cle Elum, taken
on March 1, contained 4 embryos and one from the Teanaway River near Cle
Elum held 2 embryos on February 28. One from Swauk Creek, Kittitas
County, on the eastern slope of the Cascades, had 3 embryos on February
12. A young beaver was born to a captive animal on May 18. Its mother
was taken at Soos Creek in southeastern King County. This baby weighed
884 grams.
The majority of the beavers trapped are small animals, measuring from
725 to 900 mm. (total length) in February, and weighing from 10 to 20
pounds. These are kits, probably one and two years old. It is rather
difficult to divide these animals into two age groups but probably the
first year young (7 to 11 months old) weigh from 10 to 15 pounds and
measure between 725 and 800 mm. in total length. Two-year olds (19 to 23
months) measure from 800 to 925 mm. and weigh from 15 to 25 pounds. They
measure approximately 1050 mm. the third year, when they become adult,
and weigh in the neighborhood of 45 pounds. Individuals occasionally
weigh more than 50 pounds; these are probably old adults.
Damage by beavers is limited. Their dams occasionally flood roads and
rarely fields. In some parts of eastern Washington, where fruit raising
is an important industry, an individual beaver may cause considerable
damage by cutting valuable trees. Ornamental trees may be damaged near
the larger cities. Beavers living in Lake Washington in almost the
center of the city of Seattle, caused some damage to ornamental trees on
the University of Washington Golf Course. Canals and dams in small
streams and ditches in areas where stock raising is practiced, flood
stock food and sometimes form mudholes or bogs where stock might be
trapped. Where individual beavers are doing damage they are trapped and
killed, or are live-trapped and transported to more favorable habitats.
In places where any beaver may be potentially dangerous, as in the
fruit-growing areas of eastern Washington or stock-raising areas in
western Washington, their numbers should be kept down by continued
trapping.
[Illustration: FIG. 102. Forest road flooded by beavers which built a
dam on the upstream (left) side of a bridge; Tronson Creek, Blewett
Pass, Wenatchee National Forest, May 13, 1938. (Fish and Wildlife
Service by Victor B. Scheffer, No. 30.)]
Probably the greatest value of beavers lies in the impounding of water
by their dams. This is especially true in the arid mountains of eastern
Washington and in the logged-off or burned-over parts of western
Washington. These ponds prevent erosion, raise the water table and so
stimulate the growth of vegetation, insure greater regularity of stream
flow, provide suitable water for trout and muskrats as well as some
breeding grounds for waterfowl. On burned-over or logged-off land, the
greatest, and often the only, growth of new conifers is in the vicinity
of beaver ponds. In the vicinity of beaver dams, rich growths of willows
and other deciduous vegetation provides food and cover for deer and
fur-bearing mammals.
[Illustration: FIG. 103. Distribution of the beaver in Washington. A.
_Castor canadensis leucodonta._ B. _Castor canadensis idoneus._]
Trapping of beaver for their fur at present is not a private enterprise
but controlled trapping by the state adds to public funds.
=Castor canadensis leucodonta= Gray
_Castor canadensis leucodonta_ Gray, Ann. and Mag. Nat. Hist., 4
(ser. 4):293, October, 1869.
_Castor canadensis pacificus_ Rhoads, Trans. Amer. Philos. Soc.,
19 (n. s.):422, September, 1898 (type from Lake Keechelus,
Kittitas County, Washington).
_Type._--Obtained by Dr. Robert Brown, probably on Vancouver
Island, British Columbia.
_Racial characters._--Large size; reddish color; elongate skull.
_Distribution._--Found over all but the southwestern corner of the
state. The most westward locality from which specimens have been
examined is Lake Crescent (U. S. N. M.).
_Remarks._--The good series of beaver skulls available from several
areas of Washington has led to careful comparison of Washington material
with specimens from Vancouver Island. Skulls from extreme southwestern
Washington are small and decidedly short, being referable to the race
_idoneus_. No satisfactory way of distinguishing between the others
could be found and all are consequently referred to the earliest named
form, _leucodonta_.
=Castor canadensis idoneus= Jewett and Hall
_Castor canadensis idoneus_ Jewett and Hall, Jour. Mamm., 21:87,
February 15, 1940.
_Type._--Obtained at Foley Creek, tributary to Nehalem River,
Tillamook County, Oregon, by C. Leach on December 15, 1914; type in
California Museum of Vertebrate Zoölogy.
_Description._--Similar to _leucodonta_ but smaller, darker, with
shorter and wider skull.
_Distribution._--Lowlands near the mouth of the Columbia River.
Specimens from Puget Island (U. S. N. M.) have been examined.
=Onychomys leucogaster fuscogriseus= Anthony
Northern grasshopper mouse
_Onychomys leucogaster fuscogriseus_ Anthony, Bull. Amer. Mus. Nat.
Hist., 32: 11, March 7, 1913.
_Type._--Obtained at Ironside, Malheur County, Oregon, by H. E.
Anthony, in 1912; type in American Museum of Natural History.
_Measurements._--Nine males and 5 females from Franklin, Benton,
and Walla Walla counties, Washington, average, respectively: total
length 132.3, 133.0; length of tail 35.8, 35.6; hind foot 19.2,
19.6; ear 17.6, 17.6; weight 23.3, 24.1 grams.
_Distribution._--The Columbian Plateau, southeastern Washington,
and the Yakima Valley, ranging north to Douglas (Taylor and Shaw,
1929: 21), west to Yakima (M. V. Z.), east to Asotin (Taylor and
Shaw, 1929: 21) and south to Wallula (Taylor and Shaw, 1929: 21).
[Illustration: FIG. 104. Distribution of the northern grasshopper
mouse, _Onychomys leucogaster fuscogriseus_, in Washington.]
_Description._--A mature grasshopper mouse is slightly larger than a
house mouse; the head and body measure about 4 inches and the tail about
1-1/4 inches; it may be recognized by the rather plump body, naked
ears, short, thick and tapering tail and soft, dense fur. The upper
parts of adults are buffy. Younger animals are blue-gray above.
Underparts and tail are white.
Grasshopper mice of two species range over much of northern Mexico and
the western United States. The species occurring in Washington,
_leucogaster_, is found from southern Manitoba to northern Mexico, and
from the Pacific states east to North Dakota. This species is
characteristic of the Upper Sonoran Life-zone, and usually is associated
with sagebrush and greasewood. It prefers open areas of sand and avoids
heavy cover, and seems to be strictly nocturnal. It eats vegetation,
seeds, insects, or the flesh of other mice. According to Bailey (1936:
178), grasshopper mice pursue, catch and kill other mice. They hunt by
scent and follow tracks like a wolf. They make a sound, or "call," like
a miniature wolf howl. They are said to be rather docile and make
friends with humans quickly.
On some occasions grasshopper mice are locally abundant, but for the
most part they are rather uncommon over their range. Usually one is
taken in about 200 traps set in suitable habitats. They do not
hibernate; one was caught at Moses Lake, Grant County, on a freezing
winter night.
The grasshopper mouse is almost always associated with the pocket mouse
(_Perognathus parvus_), deer-mouse (_Peromyscus maniculatus_), and often
the harvest mouse (_Reithrodontomys megalotis_). The same snakes, owls,
and carnivorous mammals that prey on these mice doubtless eat also the
grasshopper mouse.
R. D. Svihla (1936: 172) determined the gestation period of 3 lactating
grasshopper mice captured at Lind, Adams County, as 33, 39 and 47 days.
A non-lactating female gave birth to a litter in 32 days. Young varied
from 2 to 5 in number and were pink and hairless at birth, with eyes and
ears closed.
=Reithrodontomys megalotis megalotis= (Baird)
Western harvest mouse
_Reithrodon megalotis_ Baird, Mamm. N. Amer., p. 451, 1857.
_Reithrodontomys megalotis nigrescens_ Howell, N. Amer. Fauna,
36:32, June 5, 1914 (type from Payette, Idaho).
_Reithrodontomys megalotis megalotis_ Bailey, N. Amer. Fauna,
55:189, August 29, 1936.
_Type._--Obtained between Janos, Chihuahua, and San Luis Springs,
New Mexico, by C. B. R. Kennerly, in 1855; type in United States
National Museum.
_Measurements._--Five males and 6 females, showing moderate wear on
the third upper molars, from Walla Walla County, average,
respectively: total length 141, 137.5; length of tail 71.8, 68.1;
hind foot 17.2, 16.7; weight (males only) 10.5 grams. A female, 136
mm. long, from Grant County, weighed 9.5 grams. Over the range of
_megalotis_ in the United States, males average consistently larger
than females in length of the hind foot and consistently less in
length of head and body.
_Distribution._--The Columbian Plateau, the Upper Sonoran
Life-zone area west of the Columbia River and south of the
Wenatchee Mountains in Kittitas, Yakima, and Benton counties, the
north side of the Columbia River in Klickitat County, and Okanogan
County east of the Okanogan River. Marginal localities are:
Timentwa (W. W. D.) on the north, Maryhill (M. V. Z.) on the west,
Wallula (M. V. Z.) on the south, and Colfax (Taylor and Shaw,
1929: 21) on the east.
[Illustration: FIG. 105. Distribution of the western harvest mouse,
_Reithrodontomys megalotis megalotis_, in Washington.]
_Remarks._--Harvest mice from the states of Washington, Oregon, Idaho,
Utah, Nevada, California, Arizona, and New Mexico were examined to
ascertain the validity of the name _Reithrodontomys megalotis
nigrescens_ Howell (type from Payette County, Idaho). No cranial
characters or measurements could be found to separate _nigrescens_ from
_megalotis_. Specimens from Washington, Oregon, and west-central Idaho,
within the range ascribed to _nigrescens_, averaged slightly darker in
color with a more distinct, blackish dorsal line than specimens from New
Mexico. This difference is slight, and specimens from any one locality
vary greatly in color. Some Washington specimens are as pale as the
palest material from New Mexico, and some of the darkest _nigrescens_
can be matched by specimens of _megalotis_ from Arizona and New Mexico.
This slight color variant is not worthy of recognition as a distinct
subspecies, and I agree with Howell (1939: 390) that _nigrescens_ is a
synonym of _megalotis_.
_Description._--The western harvest mouse is about the size and shape of
the common house mouse. The length of the tail is approximately equal to
the length of the head and body. The tail is slim and lightly haired.
The upper parts are brownish buff lightly washed with blackish. A faint
but distinct dark dorsal stripe is usually present. The underparts are
white. From _Mus_ and _Peromyscus_, _Reithrodontomys_ can be
distinguished by the grooves on the anterior face of the upper incisors
and the long brown hairs at the bases of the ears.
This genus reaches the extreme northern limit of its distribution in the
state of Washington, where it ranges to the Canadian border. A single
subspecies occurs in Washington. The harvest mouse is a resident of the
Upper Sonoran Life-zone and it is most abundant in dense growths of
grass, weeds, and other vegetation. Along the Yakima River, near
Ellensburg, it was abundant in thick, river-side jungle. Near Yakima
many specimens were taken in a marsh of cattails and tules. In the Grand
Coulee they live in thick grass. Near Moses Lake several were found in
their nests in a thick growth of tumbleweed. Harvest mice occur also,
although never in great numbers, in relatively open areas. At the
Potholes near Moses Lake, Grant County, a few were caught on sand dunes
among scattered bushes of sage. They were taken on sagebrush flats in
several localities. Gray (1943: 191) estimates their numbers in the
sagebrush area of the Yakima Valley at 5 per acre.
Where harvest mice live in dense vegetation they make small runways and
food piles similar to those of _Microtus_ but in more open areas they
leave no perceptible signs. Near Yakima the nest of a harvest mouse was
found among the roots of an overturned apple tree. This nest was an
irregular ball composed of fine grasses and shredded bark closed above,
with a side entrance and a central cavity three inches in diameter. Near
Moses Lake three nests of harvest mice were discovered on the ground
under cover of a dense growth of tumbleweed, and six live harvest mice
were captured in the same area. These nests were cuplike, open above,
and were composed of dry grasses, bits of weeds, and newspaper. The
smoothly rounded inner cups measured about three inches in diameter.
Embryos were found in harvest mice in Washington from March to April and
numbered 3 to 6.
=Peromyscus maniculatus= (Wagner)
Deer mouse
_Description._--The deer mouse is slightly larger than the house mouse,
the head and body measuring from 3-1/2 to 4 inches. The length of the
tail varies considerably in the several races, ranging from
approximately 2-1/2 inches in _gambelii_ to 4 inches or more in some
individuals of _oreas_. The eyes are large and protrude slightly. The
ears are large, erect and naked. The tail is sparsely furred with short,
posteriorly directed hairs. The color of the upper parts varies from
yellowish buff in _gambelii_ to reddish brown in _oreas_ and dusky in
_austerus_. Young deer mice are gray or bluish gray above. Underparts
and feet are white. The tail is bicolored, being dusky above and white
below.
[Illustration: FIG. 106. Deer mouse (_Peromyscus maniculatus
austerus_), in captivity, Seattle, Washington, September 18, 1939.
(Fish and Wildlife Service photo by Victor B. Scheffer, No. 723.)]