These cute little chaps were found cozily at rest in their nest in
a pine. They were routed out, however, long enough to have their
portraits taken. An effort was made to include the mother, but without
success (see page 556).]
=THE POCKET GOPHERS= (=Geomys bursarius= and its relatives)
(_For illustration, see page 515_)
With the exception of the moles no other extensive group of American
land mammals is so highly specialized for a peculiarly restricted mode
of life as the pocket gophers. They form a strongly marked family, the
Geomyidæ, which includes various genera and many species, all very
similar in external form, but varying from the size of a large mouse to
a massively formed animal equalling a large house rat in weight.
Without exception they are powerfully built for their size, the head
and front half of the body being extraordinarily muscled to meet the
demands of their mode of life. The broad blunt head is joined almost
directly on the body. The eyes are small and have the restricted vision
to be expected from animals living underground. The ears are reduced
to little fleshy rims about the openings, and the short naked tail is
provided with nerves, which render it useful as an organ of touch.
The front teeth are broad, cutting chisels, and on each side of the
mouth is a large pocket in the skin used for gathering and carrying
food. On the front feet are long claws, which, when not being used to
dig or handle earth, are doubled under, against the soles of the feet,
so that the gopher walks on the back of them much as the ant-eater
walks on its folded claws.
Peculiar to North America, pocket gophers occupy a great area extending
from Illinois, Florida, and the Gulf of Mexico to the Pacific coast,
and from the plains of the Saskatchewan, in Canada, southward to
Panama. Their vertical range within these limits extends from sea level
to timber-line, at above 13,000 feet on some of the high volcanoes of
Mexico. The family attains its greatest development in that wonderful
region of plains and volcanoes lying about the southern end of the
Mexican table-land.
In the United States these animals are best known as “gophers,” but
in the range they occupy in the Southeastern States they are called
“salamanders” and in Mexico are widely known as “tuzas.” As a rule they
frequent treeless areas, but are found also in many types of forests
from among the palms and other trees of the tropical lowlands to the
oaks, pines, and firs on the mountain sides.
All members of the family live wholly underground, in many-branched
horizontal tunnels, which they are continually extending in winding and
erratic courses about their haunts. The tunnels are from two to about
five inches in diameter, according to the size of the animal, and while
usually less than six inches below the surface, the approaches to the
nest and storage chambers sometimes drop abruptly two or three feet
below the regular working tunnels to the level of the living quarters.
At intervals along the tunnels short side branches are used as sanitary
conveniences, thus enabling the occupant to keep the main passageways
in a habitable condition.
The courses of the underground workings are roughly indicated on the
surface by series of piles of loose earth brought up through short
side passages as the tunnels are extended. These little miners’ dumps
of earth vary with the size of the animal, sometimes containing more
than two bushels. The outlets of the passages leading to the surface
are kept plugged with loose earth. When these animals are numerous the
ground is thickly dotted in all directions with earth piles, and the
caving caused by the network of tunnels just below the surface renders
walking difficult. The perpetual industry of these rodent miners
outclasses that of the proverbial beaver.
Gophers are both diurnal and nocturnal, the gloom of their tunnels
scarcely varying except when one of the outlets is temporarily opened.
They are averse to light, and if the plug to a freshly made opening
is removed the observer may soon catch a glimpse of the owner as he
suddenly thrusts his head into view for a moment before again plugging
the door with earth.
Gophers dig their tunnels by using their teeth and the strong claws on
the front feet. The loose earth is pushed along the tunnel by the head,
the palms of the front feet, and the breast in little jerky movements
until it is ejected on the surface dump.
Owing to their poor sight, heavy bodies, and short legs, gophers are
clumsy and deliberate in their movements and peculiarly helpless in
the open. Apparently appreciating this, they rarely venture from their
underground shelter by day except when in grain fields or similar
sheltering vegetation. Here they sometimes run out two or three feet to
cut down a succulent stalk and drag it hastily within the entrance of
the tunnel, where it is cut into short sections and placed in the cheek
pouches if to be used as food or left on the dump if the object of the
cutting is finally to secure the seeds or head of ripening grain.
During the mating season in spring pocket gophers run about clumsily
from one burrow to another and may often be seen on the surface by the
light of the rising sun. Most of their short trips above ground are
made at night, when they sometimes swarm out and wander over a limited
territory. Their night wanderings are proved in California by the many
bodies which the morning light often reveals in the sticky crude oil
on newly oiled roads which the gophers have tried to cross.
From one to seven young are born in a litter, but whether there is more
than one litter in a season or not is unknown. The young when about
half grown migrate to unoccupied ground sometimes one or two hundred
yards from the home location and make tunnels of their own.
The food of pocket gophers consists mainly of tubers, bulbs, and other
roots, including many of a more woody fiber. Whole rows of potatoes or
other root crops are cleaned up by the extension of tunnels along them.
Sometimes the animals follow a row of fruit trees, cutting the roots
and killing tree after tree. In grain and alfalfa fields they are great
pests, and in irrigated country their burrows in ditch banks often
cause disastrous breaks.
The big tropical species sometimes exist in such numbers as to render
successful agriculture very difficult. Sugar-cane planters in many
parts of Mexico and Central America are compelled to wage unremitting
war on them to avoid ruin. I know of an instance on a plantation
in Vera Cruz in which thousands were killed during a single season
without stopping the damage from these pests, which swarmed in from the
adjacent area.
The large external cheek pouches of pocket gophers are used solely for
gathering such food supplies as seeds, small bulbs, and sections of
edible roots or plant stems and transporting them to storage chambers
located along the sides of the tunnels. Food is placed in the pouches
by deft sidewise movements of the front feet used like hands, and so
quick are they that the motions of the feet can scarcely be detected.
The pockets are emptied by placing the front feet on the back ends
of the pouches and pushing forward, thus forcing out the contents.
In their tunnels gophers run backward and forward with almost equal
facility, the sensitive naked tail serving to guide their backward
movements.
Pocket gophers are stupid solitary little beasts, with surly
dispositions, and fight viciously when captured or brought to bay. This
attitude toward the world is justified by the host of enemies ever
ready to destroy them. Among their more active foes are snakes and
weasels, which pursue them into their tunnels; and badgers, which dig
them out of their runways.
They are also persistently hunted day and night by foxes and coyotes.
Moreover, by day various kinds of hawks watch for them to appear at the
entrances of their dens, and by night the owls, ever alert, capture
many.
When one gopher intrudes into the tunnel of another the owner at once
fiercely attacks it. In some places I have seen Mexicans take advantage
of this characteristic pugnacity by fastening the end of a long string
about the body of a captured gopher and then turning it into an
occupied tunnel, through a recently made opening. The owner, scenting
the intruder, would immediately attack him, the combatants locking
their great incisors in a bulldog grip.
The movements of the string would give notice of the encounter, and
by pulling it out steadily both animals could be drawn forth and the
enraged owner of the burrow dispatched. In this manner I have known an
Indian to catch more than a dozen gophers in a few hours.
Pocket gophers are active throughout the winter even in the coldest
parts of their range, but in many places must rely largely on food
accumulated in their storage chambers.
Melting snow in the mountains and in the North reveals the remains of
many tunnels made through it along the surface of the ground. These
snow tunnels are often filled for long distances with loose earth
brought up from underground, and after the snow disappears in spring
the curious branching earth forms left, winding snakelike through the
meadows, are a great puzzle to those who do not know their origin.
In a state of nature pocket gophers are constantly bringing the subsoil
to the surface and burying humus. Over an enormous area they exist in
such countless thousands that their work, like that of angleworms,
is often of the most beneficial character. On bare slopes, however,
their work is highly injurious, as it greatly increases erosion of the
fertile surface soil and thus has its direct influence in changing
world contours.
When civilized man arrives in their haunts and upsets natural
conditions with cultivated crops the new food supply stimulates an
increase in the gopher population and their activities immediately
become excessively destructive and necessitate unremitting warfare
against them.
=THE KANGAROO RATS= (=Dipodomys spectabilis= and its
relatives)
(_For illustration, see page 518_)
The desert regions of western North America have developed several
peculiar types of mammals, and among them are none handsomer or more
interesting than the kangaroo rats. These rodents, despite their name,
are neither kangaroos nor rats, but are near relatives of the pocket
mice, which share their desert haunts.
All are characterized by a kangaroo-like form, including small fore
legs and feet, long hind legs and feet for jumping, and a tail longer
than the body to serve as a balance. In addition, they have large,
prominent eyes and are provided with skin pouches on each side of the
mouth for use in holding food to be carried to their store chambers.
The color pattern, like the form, of the kangaroo rats is practically
uniform throughout the group. Both are well shown in the accompanying
plate of _Dipodomys spectabilis_, the largest and most strongly marked
species. Its total length is from 12 to 14 inches; most of the other
species are much smaller.
Kangaroo rats of many species are distributed over most of the arid
and semiarid regions of the United States and Mexico, from Nebraska,
Oklahoma, and the Gulf Coast of Texas west to the Pacific coast,
and from Montana and Washington southward to the Valley of Mexico
and throughout Lower California. They are especially numerous in the
southwestern deserts, where they are the oddest and most picturesque of
animals.
Although they have no near relatives in the Old World, some of the
African and Asiatic jerboas are externally almost perfect replicas of
the kangaroo rats in every detail of form, color, and color pattern,
even to the tail markings. This extraordinary likeness in appearance of
two widely separated and unrelated animals is made doubly significant
by the fact that both live in deserts and have similar habits.
Peculiarly desert animals, kangaroo rats live like the pocket mice,
without drinking, but obtain the necessary water through their
digestive processes. They are most numerous in sandy areas, and there
the earth is sometimes so riddled by their burrows as to render
horseback riding difficult.
Kangaroo rats are nocturnal and always live in burrows dug by
themselves. As a rule they prefer soft or sandy ground, but some
species occupy areas where the earth is hard and rocky. The burrows
of some species have only one or two entrances with a small amount of
earth thrown out, but others make little mounds with several openings,
entering usually nearly on a level or at a slight incline. These
openings are nearly always conspicuous, and while frequently near
bushes, no effort appears ever to be made to conceal them, and a little
trail often leads away through the soft earth.
The large _Dipodomys spectabilis_, which lives mainly in New Mexico
and Arizona, constructs the most notable of all the dwelling places of
these animals. From its underground workings it throws up large mounds
of earth, which gradually increase in size with the length of time
they are occupied until they are sometimes more than 3 feet high and
15 feet or more in diameter. From three to a dozen burrows enter these
mounds, usually at the surface level of the ground, but some are on the
slopes of the mound. The mounds, usually located in open ground, with
their round entrance holes from four to five inches in diameter, are
extremely conspicuous.
Although generally scattered at varying distances from one another, the
mounds are sometimes grouped in colonies. Well-worn trails three or
four inches broad lead away from the entrances, some to other mounds
showing neighborly intercourse and others far away to the feeding
grounds, sometimes 200 or 300 yards distant. One of the openings at
the side of the mound is usually the main entrance, and by day this is
ordinarily kept stopped with fresh earth. Within the mound and farther
under ground are dug a series of ramifying passages, among which are
located roomy nest chambers and store-rooms for food.
Kangaroo rats are not known to hibernate in any part of their range.
They lay up food for temporary purposes at least and do not go abroad
in stormy or cold weather. The northern species and those on the
colder mountain slopes must make large store against the winter needs.
Their food consists mainly of seeds, leaves of several plants, and of
little plants just appearing above ground. Tiny cactus plants and the
saline fleshy leaves of _Sarcobatus_ are often among the kinds gathered
for food.
The big _Dipodomys spectabilis_ appears to be more social than most of
its kind, as several may be caught in a single mound, and, as already
said, well-worn trails lead from mound to mound. A little noise made
just outside one of these mounds usually brings a reply or challenge
in the form of a low drumming or thudding noise, no doubt made by the
animal rapidly striking the ground with its hind feet like a rabbit or
wood rat.
When caught they at first struggle to escape, but, like a rabbit, do
not offer to bite, and soon become quiet. They have from two to six
young, which may be born at any season. Nothing appears to be known
concerning the number of litters in a year.
When in camp at San Ignacio, in the middle of the desert peninsula
of Lower California, I had an unusual opportunity to learn something
of the habits of one of the smaller species of kangaroo rat abundant
there. The moon was at its full, and in the clear desert air its
radiance rendered objects near at hand almost as distinct as by day.
Scattered grains of rice and fragments of food on the ground about the
cook tent attracted many kangaroo rats and pocket mice.
During several nights I passed hours watching at close range the habits
of these curious animals. As I sat quietly on a mess box in their
midst both the kangaroo rats and the mice would forage all about with
swift gliding movements, repeatedly running across my bare feet. Any
sudden movement startled them and all would dart away for a moment, but
quickly return.
Although the kangaroo rats did not become so fearless and friendly as
the pocket mice, they were so intent on the food that at times I had
no difficulty in reaching slowly down and closing my hand over their
backs. I did this dozens of times, and after a slight struggle they
always became quiet until again placed on the ground, when they at once
renewed their search for food as though no interruption had occurred.
One night, to observe them better, I spilled a small heap of rice on
the sand between my feet. Within two or three minutes half a dozen
kangaroo rats had discovered it and were busily at work filling their
cheek pouches with the grains and carrying them away to their store
chambers.
While occupied in this rivalry for food they became surprisingly
pugnacious. If one was working at the rice pile and another rat or a
pocket mouse approached, it immediately darted at the intruder and
drove it away. The mode of attack was to rush at an intruder and,
leaping upon its back, give a vigorous downward kick with its strong
hind feet. Once I saw a pocket mouse kicked in this way. It was knocked
over and for a minute or more afterwards ran about in an erratic
course, squeaking loudly as though in much pain.
Sometimes the pursuit of one kangaroo rat by another continued for
twenty yards or more. By the time the pursuer returned another would
be at the rice pile and it would immediately dash at the victor of
the former fray and drive him away. In this way there was a constant
succession of amusing skirmishes.
Sometimes an intruder, bolder than the others, would run only two or
three yards and then suddenly turn and face the pursuer, sitting up on
its hind feet like a little kangaroo. The pursuer at once assumed the
same nearly upright position, with its fore feet close to its breast.
Both would then begin to hop about watching for an opening. Suddenly
one would leap at the other, striking with its hind feet exactly like
a game cock. When the kick landed fairly on the opponent there was a
distinct little thump and the victim rolled over on the ground. After
receiving two or three kicks the weaker of the combatants would run
away.
The thump made by the kick when they were fighting solved the mystery
which had covered this sound heard repeatedly during my nights at this
camp. The morning light revealed a multitude of little paired tracks
made by the combatants in these battles. Such tracks in the sand have
been referred to as the “fairy dances” of these beautiful little
animals, but the truth revealed proves them to be really “war dances.”
=THE BANDED LEMMING= (=Dicrostonyx nelsoni= and its relatives)
(_For illustration, see page 519_)
Banded lemmings are unique among the mouse tribe in their change from
the rufous brown, or gray summer coat to pure white in winter. With
the assumption of the white winter fur a thick, horny, padlike growth
develops on the underside of the two middle claws of the front feet,
which is molted in spring when the winter coat is lost. For an animal
living in the far North the usefulness of a white coat in winter is
evident, but no good reason is apparent for these curious claw-pads.
The summer coat varies remarkably in color and color pattern, and many
of the lemmings in their beautiful shades of chestnut, browns, or grays
are very handsome. They are more heavily proportioned than field mice
and the very long fluffy fur, which completely conceals the rudimentary
ears and tail, tends to exaggerate their size.
The banded lemmings form a strongly marked group, containing a number
of species inhabiting circumpolar regions. In North America they
occur nearly everywhere in the arctic and subarctic parts, including
Greenland, most of northern Canada, including the Arctic islands, and a
large part of Alaska, including some of the Aleutian Islands.
They range as far northward as vegetation affords them a proper food
supply and have been well known to many of the explorers of those
stern northern wilds. To the southward they extend into the subarctic
northern forests, where they usually keep to the open barren areas.
Not much is known of their life histories on this continent. They are
mainly nocturnal and live in burrows from two to three feet long,
ending with a nest chamber four or five inches in diameter, warmly
lined with grass and moss. Near the nest there is usually a branch
burrow a foot or more long which is used for sanitary purposes and as a
place of refuge when the main burrow is invaded.
In the nests during early summer litters generally containing about
three young are brought forth. Ordinarily the burrows open in
unsheltered places, but in wooded regions may be under a log or beneath
a bush or the roots of a tree. No runways lead out from the burrows as
is customary with many of their relatives. They are active throughout
the winter, making many tunnels along the surface of the ground under
the snow, which are revealed when it melts in spring.
These surface tunnels are their foraging roads, safe from most of the
fierce storms which rage overhead. At times, however, the snowy shelter
is blown away or some other cause brings the lemmings to the surface,
where they blunder aimlessly about, soon to be captured by some enemy
or to perish from the cold. As their infrequent appearance on top of
the snow is usually during storms, the Alaskan Eskimos have a legend
that these white lemmings live in the land above the stars and descend
in a spiral course to the earth during snowstorms.
Although banded lemmings never become so extraordinarily numerous over
great areas as the brown species, they become very abundant at times in
the barren grounds of Canada and the Arctic islands and migrate from
one part of their range to another. The best observation in regard to
this was made by Rae in June at the mouth of the Coppermine River. On
the west bank of the river north of the Arctic Circle he encountered
thousands of them speeding northward.
The ice on some of the smaller streams had broken up and he was amused
to see the little animals running back and forth along the banks
looking for a smooth place in the stream, indicating a slow current,
where they could swim across. Having found such a place, they at once
jumped in and swam quickly to the opposite side, where they climbed out
and, after shaking themselves like dogs, continued their journey as
though nothing had happened.
During the years I lived in northern Alaska the advent of winter was
marked by invasion of the storehouses by many brown lemmings and other
mice, but banded lemmings rarely appeared. When occasionally captured
alive, the old ones fought viciously, but the young were gentle and
quickly became tame and interesting pets. Their skins were highly
prized by the little Eskimo girls to make garments and robes for their
walrus ivory dolls.
=THE BROWN LEMMING= (=Lemmus alascensis= and its relatives)
(_For illustration, see page 579_)
Few small mammals are so well known in far northern lands as the brown
lemmings. They form a small group of species having a close general
resemblance to some of the field mice, from which, however, they may
at once be distinguished by their much heavier proportions, extremely
short tails, and the remarkable length of the hair on their backs and
rumps.
They inhabit most of the arctic and subarctic lands of both Old and New
Worlds. In North America they are known from the northernmost lands,
beyond 83° north latitude, to the southern end of Hudson Bay, and
throughout most of northern Canada and all of Alaska, including the
islands of Bering Sea.
The extraordinary migrations of these lemmings have attracted attention
far back in the early history of northern Europe. At intervals, through
favorable conditions, they become superabundant over a large area,
and then a sudden resistless desire to migrate in a certain direction
appears to seize the entire lemming population. The little beasts start
in a swarming horde, sometimes containing millions, and traverse the
country.
In their travels they appear indifferent to all obstacles and
with dogged and unwavering persistence swim the streams and lakes
encountered on their way. Similar migrations have been observed at
various points in Arctic America, several of them in Alaska, where the
lemmings abound on the open tundras.
These migrations sometimes continue for more than one season, the
animals meanwhile being killed in countless numbers by disease, by
accident in field and flood, and, in addition, through the heavy toll
taken from their numbers by their winged and four-footed foes, which
always gather in numbers to accompany them.
The migrations sometimes wear out through the diminution in numbers,
and sometimes when they reach the sea, as in Norway, they are said to
enter the water and swim offshore until they perish. When one of these
swarms of rodents passes through a farming district it cleans up the
crops and other surface vegetation like a visitation of locusts.
These lemmings do not hibernate, but, active throughout the severest
winters, are abroad almost equally by day and by night. Their burrows
consist of winding tunnels, often many-branched and with more than one
opening. A dry bed of peat or a dense growth of moss is often pierced
by a network of them. Well-defined runways often lead away from the
burrows or from the entrance of one burrow to that of another.
Their tunnels run everywhere under the snow, with occasional passages
leading to the surface. When fierce gales blow away the snow or a
winter rain melts it, many lemmings lose touch with their burrows and
wander about until they perish from cold or are caught by some enemy.
They are sometimes found several miles from shore, where they have
strayed out on the sea ice.
In winter in the fur countries, in company with field mice, they invade
storehouses and habitations in search of food. Among their enemies are
ravens and all northern hawks and owls, as well as foxes, weasels,
lynxes, bears, and other beasts of prey of all degree.
Within their underground tunnels and often in dense vegetation on the
surface lemmings make warmly lined nests of grass and moss in which
their young, from two to eight in number, are born. The young appear at
varying times, thus indicating several litters each year.
When taken alive, the old ones are fierce and courageous, growling and
fighting savagely; but several half-grown young brought me during my
residence in Alaska proved to be most amusing and inoffensive little
creatures. From the first they permitted me to handle them without
offering to bite and showed no signs of fear.
They were kept in a deep tin box, from which they made continual
efforts to escape. When I extended one finger near the bottom of the
box they would stand erect on their hind feet and reach up toward
it, using their forepaws like little hands. If my finger was lowered
sufficiently they would climb up into my hand and thence to my
shoulder, showing no sign of haste, but much curiosity, continually
sniffing with their noses and peering at everything with their bright
beadlike eyes.
They were curiously expert in walking on their hind feet, holding the
body in an upright position and taking short steps. If anything was
held just out of reach above their heads, as the point of my finger,
they would continue in an erect position for a considerable time. At
such times they would reach up with their front paws and often spring
up on their hind feet for half an inch above the floor trying to
touch it. When eating they sat upright on their haunches, like little
marmots, and held the food in their front paws.
=THE COMMON FIELD MOUSE, OR MEADOW MOUSE= (=Microtus
pennsylvanicus= and its relatives)
(_For illustration, see page 522_)
The Pennsylvania meadow mouse is a small species about as long in body
as the house mouse, but much more heavily proportioned. Its head is
rounded, the eyes small and beadlike, the legs and tail are short, and
the comparatively coarse fur is so long that it almost conceals the
short, rounded ears.
It is a typical representative of a group of small mammals commonly
known as field mice, or “bear mice,” which includes a great number of
species closely similar in general appearance, but varying much in
size. In England they are termed voles, and large species living about
the water in England and northern Europe are known as “water rats.”
Field mice are circumpolar in distribution and abound from the
Arctic barrens, beyond the limit of trees, to southern Europe and the
Himalayas, in the Old World, and to the southern United States and
along high mountains through Mexico and Guatemala, in Central America.
They occur in most parts of the United States except in some of the
hotter and more arid sections.
As a rule field mice prefer low-lying fertile land, as grassy meadows,
but the banks of streams, the rank growths of swamps and marshes, the
borders of damp woodlands, the grassy places on Arctic tundras, or the
dwarfed vegetation of glacial slopes and valleys above timber-line on
high mountains furnish homes for one species or another.
Two, and even three, species of field mice are sometimes found in the
same locality, but each kind usually occupies a situation differing in
some way from that chosen by the others. Some occupy comparatively dry
ground and others, like the European water rat, live in marshes and are
almost as aquatic as the muskrat. Most species living about the water
are expert in diving and in swimming, even under water. In streams
inhabited by large trout they are often caught and eaten by the fish.
The presence of field mice is nearly always indicated by smoothly worn
little roads or runways about an inch in width, which form a network
among the vegetation in their haunts. These runways lead away from the
entrances of their burrows and wind through the vegetation to their
feeding grounds. They are kept clean and free from straws and other
small obstructions, so that the owners when alarmed may run swiftly to
the shelter of their burrows. Fully conscious of their helplessness,
meadow mice are as cautious as the necessities of existence will permit.
Their burrows are often in the midst of grassy meadows, as well as
under the shelter of logs, rocks, tussocks of grass, or roots of trees,
and lead to underground chambers filled with large nests of dry grass,
which shelter the owner in winter and often in summer. The summer nests
in many places, especially in damp meadows or marshes, are made in
little hollows in the surface or in tussocks of grass. In these nests
several litters containing from four to eleven young are born each year.
It is rarely that an observer is located where he can study the
every-day lives of little animals like the meadow mice and at the same
time go on with his regular occupation. At one of my mountain camps in
Mexico I fortunately pitched my tent on a patch of lawn-like grass in
front of the ruins of an abandoned hut. Runways of field mice formed a
network everywhere in the surrounding growth of grass and weeds.
[Illustration: ANTELOPE JACK RABBIT
_Lepus alleni_]
For hours at a time as I worked quietly in the tent the many mice,
unconscious of my presence, came silently along their little roads
through the tall vegetation to the border of the short grass. Just
within the shelter of the tall growth they would each time stop and
remain watchfully immovable for a half minute, and then, if everything
was quiet, make a swift run two or three feet into the open, bite
off a tender little grass blade and dash back to the sheltered road.
There they would sit up squirrel-like, holding the grass blades in
their forepaws and eating them rapidly, or would sometimes carry the
food back to the burrows.
[Illustration: CALIFORNIA JACK RABBIT
_Lepus californicus_]
[Illustration: VARYING HARE, or SNOWSHOE RABBIT
_Lepus americanus_]
Occasionally as the mice darted into the open I made a slight squeaking
noise and perhaps two or three in sight at the time would instantly
turn and dash back into the sheltered road, sometimes not reappearing
for a long time. Again and again I saw them come into the open for
food, and before securing it suddenly scamper back in a panic without
apparent cause for alarm.
Eternal vigilance is the only defense such animals have, and despite
their watchfulness myriads of them are devoured daily by a large number
of rapacious birds and mammals, including even such huge beasts as
the great Alaskan brown and grizzly bears, which dig them from their
burrows on grassy northern mountain sides.
Despite their numerous natural enemies field mice are so prolific they
continue among the most destructive of agricultural pests. They are so
obscure and the damage by a single mouse appears so insignificant, that
it requires a knowledge of their habits, their wide distribution, and
their enormous numbers to appreciate what a serious drain they are on
the farmer’s income, even when in their normal numbers.
In summer they feed on growing grass, clover, alfalfa, and grain,
seeds, bulbs, root crops, and garden vegetables. In fall they
congregate under shocks to feed on the grain, and in winter often do
enormous injury to young or even well-grown fruit and other trees by
gnawing off the bark on the base of the trunk and roots, sometimes in
this way destroying entire orchards and nurseries.
One species in California destroys large quantities of raisins drying
in the field by carrying them off to some shelter, where they cut out
the seeds and leave the rest of the fruit. I have seen half a pound of
raisins under a piece of board, the result of the night’s work of a
single mouse.
While field mice are always destructive, at intervals they have sudden
and mysterious accelerations of increase and become so excessively
abundant that they are a veritable plague. Many instances of this are
on record in the Old World, where they have become so numerous as to
call forth governmental intervention.
The most notable recent outbreak of this kind in the United States took
place in the Humboldt Valley, Nevada, where, during the winters from
1906 to 1908, they swarmed over the cultivated parts of the valley and
completely destroyed 18,000 acres of alfalfa, even devouring the roots
of the plants. During this outbreak the mice in the alfalfa fields were
estimated to number as high as 12,000 to the acre.
Whenever field mice become over-abundant notice appears to go out among
their natural enemies, and in extraordinary numbers hawks, owls, crows,
ravens, sea gulls, coyotes, foxes, bobcats, weasels, and other animals
appear to prey upon them.
At no season of the year are they free from their foes, for they remain
active throughout the winter, and most species apparently lay up no
winter store of food. They travel to winter feeding places through
series of tunnels under the snow, and it is mainly at this season that
they do the most serious damage to orchards and shrubbery.
In the far North at the beginning of winter they gather in large
numbers about the fur-trading stations and other habitations, where
they persistently invade the food supplies.
Some of the northern mice, however, gather stores of food for winter. A
species living along the coast of the Bering Sea and elsewhere on the
Arctic tundra of Alaska accumulates a quart or more of little bulbous
grass roots, which are delicious when boiled. They are hidden in nests
of grass and moss among the surface vegetation, and before the first
snowfall I have seen the Eskimo women searching for them by prodding
likely places with a long stick. The roots thus taken from the mice are
kept to be served as a delicacy to guests during winter festivals.
=THE PINE MOUSE= (=Pitymys pinetorum= and its relatives)
(_For illustration, see page 522_)
The pine mice form a small group of species peculiar to North America
and closely related to the field mice. They are similar in form to the
common field mice of the Eastern States, but are usually smaller, with
much shorter tails and shorter, finer, and more glossy fur.
Most of the pine mice are limited to the wooded region of the States
between the Atlantic coast and the eastern border of the Great Plains,
and from the Hudson River valley and the border of the Great Lakes
south to the Gulf coast. Strangely enough, one species lives in a
restricted belt covered with tropical forest along the middle eastern
slope of the Cordillera, which forms the eastern wall of the Mexican
tableland, on the border between the States of Vera Cruz and Puebla.
Pine mice occupy the borders of thin forests and brushy areas, from
which they work out into the open borderlands, especially in orchards
or other places where there are scattered trees amid a rank growth of
weeds. Instead of making their runways among growing vegetation on the
surface of the ground like field mice, they live in little underground
tunnels or burrows which extend in all directions through their haunts.
These tunnels are closely like those of the common mole except that
they are smaller and have frequent openings to the surface, through
which the owners make short excursions for food. They often utilize the
tunnels of moles when conveniently located for their purposes.
The tunnels are often so near the surface that the ground is slightly
uplifted or broken as by a mole, or they are made under the fallen
leaves and other small decaying vegetable matter covering the ground
under the trees. Occasionally, when the surface soil becomes dry and
hard, the burrows are deeper, so that no surface indications can
be discovered. On account of the similarity of their burrows the
depredations of pine mice are commonly attributed to moles.
Several inches below the surface pine mice excavate oval chambers to
be used for nests or for storage purposes. The nest chambers have
several entrances from ramifying tunnels and are filled with short fine
pieces of grass, making a warm nest-ball. Here the several litters of
young are born each year. Pine mice are less prolific than field mice,
however, and the litters contain only from one to four young.
The food chambers are larger than the nest chambers, and when full of
stores are kept closed with earth. In these are stored short sections
of green or dry grasses, bulbous grass roots, and short sections of
other edible roots. One such store contained about three quarts of the
fleshy roots of a morning glory cut into short sections.
Pine mice obtain much of their food from the bark about the bases and
roots of trees, including both coniferous and deciduous species. They
kill many small trees and shrubs by girdling, or by cutting the roots
below the surface, and in this way frequently inflict severe damage in
orchards and nurseries. Owing to their underground habits they are much
more dangerous to orchards than field mice. They also do much damage by
burrowing along rows of potatoes and other root crops, upon which they
feed.
Both pine mice and field mice are serious pests to agriculture and
only by vigilant care can they be prevented from steadily reducing
the returns from farm and orchard. A mouse appears so insignificant
an enemy that the general inclination among farmers is to ignore it,
but both field and pine mice exist in such enormous numbers and are so
generally distributed that the aggregate annual losses from them are
great.
Clean cultivation in orchards, especially for some distance immediately
about the trees, is an excellent protective measure against both of
these mice. The shrubbery and fruit trees of orchards, lawns, and
gardens may be protected by the use of poisoned baits and traps as soon
as signs of pine mice or field mice are observed.
=THE RED-BACKED MOUSE= (=Evotomys gapperi= and its relatives)
(_For illustration, see page 523_)
With the exception of the banded lemmings the red-backed mice are the
most brightly colored of the smaller northern rodents. They are close
relatives of the common field mice, which they about equal in size,
but from which they are distinguished externally by rufous coloration,
finer and more glossy pelage, larger ears, and proportionately longer
tails.
The red-backed mice form a group containing a considerable number
of species distributed throughout the northern circumpolar lands,
except on the barren islands of the Arctic Sea. In North America they
occur from the Arctic tundras north of the limit of trees southward
throughout Alaska and Canada to the northern United States. With other
northern species of mammals, birds, and plants they follow the high
mountain ranges still farther southward to North Carolina, New Mexico,
and middle California.
It is true that in the far North they are numerous on the moss-grown
tundras, and in the South range above timber-line on high mountains.
As a general rule, however, they are woodland animals, whether among
the spruces, birches, and aspens of the North or farther south in the
United States in the cool fir and aspen-clad slopes of mountains. They
also frequent old, half-cleared fields, brush-grown or rocky areas, and
similar places where cover is abundant.
Although so closely related to the field mice, the red-backed species
are not known to become excessively abundant nor seriously to injure
crops. One reason for their harmlessness in this respect may be their
strong preference for forest haunts.
I once found them numerous in the grass-grown streets and yards of an
abandoned mining camp in the forest at the head of Owens River, in the
Sierra Nevada, of California. The mice were making free use of the
congenial shelter afforded by the old log cabins, and their runways and
entrances to burrows were all about under scattered boards and similar
cover.
They are abroad equally by day and by night, and for this reason are
better known to woodsmen than most of the small woodland animals. When
foraging by day among the fallen leaves and deep green vegetation they
present a most graceful and attractive sight, now moving about with
quick and pretty ways, now pausing to sit up squirrel-like to eat
some tid-bit held in the front paws and then on the alert to detect a
suspected danger and poised in quivering readiness for instant flight.
Red-backed mice usually live in underground burrows similar to those of
field mice, but generally located with more care in dry situations, the
entrances sheltered by a stump, old log, root of a tree, rock, or other
object. Ordinarily they do not make such well-defined runways as do
many field mice, and sometimes no trace of a trail can be found leading
away from their burrows. But where they travel about through small
dense vegetation, under logs and about stumps and rocks they often make
well-marked trails.
Their nests are bulky and formed of a mass of fine dry grass, moss,
and other soft material, which is sometimes located in an underground
chamber opening off the burrow and sometimes in hollow stumps and logs
or under other surface shelters. But little is known about the home
life of these mice except that they are prolific, and between April and
October have several litters containing from three to eight young in
each.
[Illustration: ARCTIC HARE
_Lepus arcticus_]
[Illustration: COTTONTAIL RABBIT
_Sylvilagus floridanus_]
[Illustration: MARSH RABBIT
_Sylvilagus palustris_]
[Illustration: PIKA, LITTLE CHIEF HARE, or CONY
_Ochotona princeps_]
They feed upon a great variety of seeds, fruits, roots, and succulent
vegetable matter and lay up stores for winter in underground chambers
or in hollow logs and similar places above ground.
With the coming of winter they gather about cabins and other
habitations in their territory and become as persistent as house mice
in searching out and raiding food supplies of all kinds. When the more
appreciated kinds of food fail they resort to gnawing the bark from
roots and bases of trunks of small deciduous trees of various kinds.
During my sledge journeys in the region about Bering Strait I found
the skins of many red-backed mice among the Eskimo children. The small
boys kept them with lemming skins as evidences of their prowess with
miniature dead-fall traps and blunt-pointed arrows, and the little
girls kept them as prized robes for the dolls carved by their fathers
from wood or walrus ivory.
=THE RUFOUS TREE MOUSE= (=Phenacomys longicaudus= and its
relatives)
(_For illustration, see page 523_)
The genus Phenacomys, to which the rufous tree mouse belongs, includes
a number of species closely similar in size and external appearance
to some of the well-known field mice. The structure of their teeth,
however, shows that they form a distinct group of animals.
So far as known, the living members of the genus are confined to the
Boreal parts of North America, where they range from the Atlantic
to the Pacific in Canada, and southward along the mountains to New
Hampshire, New Mexico, and northern California. The discovery of fossil
representatives of the genus in Hungary and England indicates that it
was formerly circumpolar in distribution.
All but one species of the genus live on the ground, inhabit burrows,
make runways through the small vegetation, and feed on grasses and
other herbage--all in close conformity with the habits of the meadow
mice.
The tree mouse, however, is a strongly aberrant member of the group. It
differs from all the others, and from all field mice, not only in its
rufous color and longer tail, but in its remarkable mode of life. It is
restricted to the humid region of magnificent forests in western Oregon
and northwestern California, where it often spends its life in the tops
of such noble trees as the Sitka spruce, the Douglas fir, and the coast
redwood. Such an amazing departure from the habits of its kind lends
unusual interest to this little animal.
Its nests are generally located high up in the trees, sometimes 100
feet from the ground, in forests where the branches of neighboring
trees interlace so that it can pass from one to another and inhabit
a world of its own, free from the ordinary four-footed enemies which
prowl below.
The nests vary in size, structure, and location. In Oregon they have
been found only in large trees at elevations varying from 30 to 100
feet. On the seashore near Eureka, California, they are placed on the
branches of small second-growth myrtle and redwood trees. Farther
inland in the same region many are in small trees, within a few yards
of the ground, on the border of heavy redwood forests.
The higher nests of the tree mice are often the deserted and remodeled
homes of the big gray tree squirrel of that region (_Sciurus griseus_)
and contain a foundation of coarser sticks than in the nests wholly
built by the mice. The larger proportion of the nests are built by the
mice and are usually composed of small twigs, fragments of a netlike
lichen, skeletons of fir, spruce, or other coniferous leaves, and the
droppings of the mice themselves. They vary from small oval structures
a few inches in diameter, located well out on the branches, to great
masses close against and sometimes entirely surrounding the tree
trunks, supported on several branches, and measuring three feet long
and two or three feet high.
The interior of these large structures is pierced with numerous
passageways and sometimes as many as five separate nest chambers are
scattered through one. Tunnels run out along each of the limbs on which
the mass rests, and if it extends all the way round one main tunnel
encircles the trunk from which these hallways branch.
Such great nests have evidently been used for a long period and have
grown with the steady accumulation of material. This has gradually
decayed and become a solid mass of earthy humus. The large nests are
usually the abodes of a single female, the homes of the males having
been found to be small and more often located away from the trunk of
the tree. The food of the red tree mouse, so far as known, consists
entirely of the fleshy parts of fir and spruce needles and the bark
from coniferous twigs.
Tree mice appear to breed throughout most of the year and have from
one to four young in a litter. They are mainly nocturnal, and when
driven from their nests by day appear rather slow and uncertain in
their movements. Those living in highly placed nests usually escape
by running out on the limbs, and pass from one tree to another if
necessary. Those in small trees usually drop quickly from limb to limb
until they reach the ground, when they run to the nearest shelter.
That these mice sometimes descend to the ground of their own volition
is probable, but the fact that the stomach of every individual so far
examined has contained only the fleshy parts of coniferous leaves
indicate that their food habits have become so fixed as to make
arboreal life a necessity.
The modification of the habits of a member of a group of
ground-frequenting animals, with a structure adapted to such an
existence, to those of a strictly arboreal animal is so strange as to
make the question of cause a puzzling one.
In the Hawaiian Islands the introduction of the mongoose has made the
common house rat arboreal in habits, and possibly in the remote past
the pressure of some ground-frequenting enemy thus affected the lives
of the red tree mouse. An animal rarely makes an abrupt change in its
habits without direct pressure from some source, and then only as a
matter of self-preservation.
=THE MUSKRAT= (=Fiber zibethicus= and its relatives)
(_For illustration, see page 526_)
The muskrat, or “musquash,” as it is widely known in the northern fur
country, is three or four times the size of the common house rat, to
which it bears a superficial resemblance. It has a compactly formed
body, short legs, and strong hind feet partly webbed and otherwise
modified for swimming. The long, nearly naked, and scaly tail is
strongly flattened vertically and in the water serves well as a rudder.
The fur is nearly as fine and dense as that of the beaver and, as in
that animal, protects its owner from the cold water in which so much of
its life is spent.
Muskrats are peculiar to North America, where they exist in great
numbers. Aquatic in habits, they have a wide distribution along streams
of all sizes and among marshes, ponds, and lakes from the Atlantic to
the Pacific, and from a little beyond the limit of trees on the Arctic
barrens south throughout most of the United States. They reach our
southern border at the delta of the Mississippi and the delta of the
Colorado, at the head of the Gulf of California.
Within this vast area they have been modified by their environment into
several species and geographic races, none of which differ much in
appearance from the well-known animal of the Eastern States.
The nearest kin of the muskrats are the short-tailed field mice, so
numerous in our damp meadows. Like the latter, the muskrat has several
litters of young each season. The young are born blind, naked, and
helpless, and number from three to thirteen to a litter. This great
fecundity has enabled the muskrats to hold their own through years of
persistent trapping.
They still occupy practically all their original range and yield a
steady toll of valuable fur each season. In 1914 more than 10,000,000
of their skins were sold in London, and other millions were handled
in America. The aggregate returns on muskrat skins are so great as to
constitute it our most valuable fur-bearer. The furriers make its skins
up in its natural color or dress and dye it and give it the trade names
of “Hudson seal,” “river mink,” or “ondatra mink.”
In suitable marshes, as on the eastern shore of Maryland, muskrats
become extremely abundant and render such areas valuable as natural
“fur farms.” One Maryland marsh containing 1,300 acres has yielded
from $2,000 to $7,000 worth of skins a year. Not only are the skins of
value, but the flesh is palatable, and is sold readily under the trade
name of “marsh rabbit” in the markets of Baltimore, Philadelphia, and
elsewhere.
There is little doubt that owners of favorably situated marshes could
derive from them a steady revenue by keeping them stocked with proper
food plants and protecting the muskrats from their enemies. The value
of these fur-bearers is becoming more and more appreciated and many
States have laws restricting the trapping season to a period in fall
and winter when the fur is prime.
In marshes about shallow lakes or bordering sluggish rivers muskrats
build roughly conical lodges or “houses,” three to four feet high, with
bases, usually in shallow water, several feet broader. These houses
are made of roots and stems of plants with a mixture of mud. An oval
chamber is left in the interior, well above the water level, to which
entrance is gained by one or more passageways opening under water.
These shelters are mainly for winter use, but the young are sometimes
born in them as well as in large grass nests among dense marsh
vegetation.
The curious conical lodges are familiar objects about marshes in the
Eastern and Northern States, and I remember seeing, a few years ago, a
specially well-formed muskrat house close to the historic bridge, at
Concord, and others along the Concord River. Within ten years muskrat
houses were common in marshy ponds in Potomac Park, Washington, where
the Lincoln Memorial Building now stands.
Where the banks of streams or lakes rise abruptly, the muskrats make
their home in dry chambers in the banks above water level at the end of
a tunnel opening either under water or close to the water level. Worn
trails lead up the banks about such places and well-marked runways are
made through the heavy reeds and marsh grasses in their haunts.
Muskrats are mainly nocturnal animals, but often move about during the
day. I have seen them repeatedly swimming close to the bank of the
Potomac a short distance above Washington. They like to carry their
food to slightly elevated points where they can overlook the water
along shore, such as the top of a projecting log, large stone, or
earthen bank, from which they plunge headlong at the first alarm. Many
a solitary canoeman gliding silently along the shore of stream or pond
at night has been startled by the disproportionately loud splash made
by a muskrat diving from its resting place.
Their food consists mainly of the roots and stems of succulent plants
varied with fresh-water clams, an occasional fish, and even by
cultivated vegetables grown in places readily accessible from their
haunts. They store up roots and other vegetable matter for winter use
and remain active throughout that season. The roots of which their
“houses” are built are frequently those used for food and sometimes
serve as winter supplies.
[Illustration: PORCUPINE
_Erethizon dorsatum_]
[Illustration: JUMPING MOUSE
_Zapus hudsonius_]
As a rule, muskrats keep near their homes in winter, making excursions
here and there beneath the ice. Sometimes the water rises and forces
them out and they wander widely in search of new locations. When
encountered at such times they show extraordinary courage and fiercely
attack man or beast. The first muskrat I ever saw was one which a
farmer met in midwinter in a snowy road in northern New York. As soon
as the man drew near, the animal rushed at him with bared teeth and
fought savagely until killed.
[Illustration: SILKY POCKET MOUSE
_Perognathus flavus_