The YELLOWBELLY MARMOT, with its reddish underparts, grizzled back, and
bushy tail, is seen by nearly all park visitors. Although it is more
common in medium altitudes in the mountains, it also may be seen high
along Trail Ridge Road, and a pair, reportedly, is living atop Longs
Peak! These rodents live in dens, usually rockpiles, into which they
pack twigs and grass to make a comfortable nest. They store up a heavy
layer of fat in the summer and hibernate during the cold winter. Their
natural food consists of grasses, berries, and roots. Their short, sharp
whistle can be heard a mile away. During the summer, hikers occasionally
see rather humanlike scenes, as marmot families sun themselves on the
"front porches" of their rockpile homes.
The TASSEL-EARED, or ABERT, SQUIRREL is an excellent example of the
zonal specialization of mammals. It is almost entirely restricted to the
ponderosa pine forest belt. Its showy ear tufts, although often absent
during the summer, set it apart from other local squirrels. It feeds
mostly on ponderosa pine seeds, the bark of twigs and young trees of
this species, and such wild fruits and succulent vegetation as are
available. The Abert squirrel builds nests in the trees and is a
familiar sight to hikers in the ponderosa pine forests. It is usually
gray-colored, but may be brown or even completely black.
Another small arboreal rodent, the SPRUCE SQUIRREL, chatters and scolds
when a stranger enters its patch of forest. It roams both the lodgepole
pine and higher spruce-fir forests with their bitter winters, yet it
does not hibernate. Even after the most severe storms it will emerge to
travel through the treetop world it occupies. Some bird enthusiasts have
little regard for it, because of its habit of eating eggs and young
birds whenever the opportunity presents itself. However, in a National
Park the squirrel's desire to live is considered to be as important as
is the bird's. A certain "balance" of population is the result, which
is, after all, one of the desirable features in an area dedicated to
preserving natural conditions.
CHIPMUNKS are particularly familiar at Trail Ridge Road parking areas.
These small squirrels are reddish-brown above, with white underparts and
with four white stripes running along the back. A definite stripe across
the face distinguishes them from the golden-mantled ground squirrels,
with which they are often found.
The GOLDEN-MANTLED GROUND SQUIRREL is often confused with the smaller
chipmunks which it joins in begging for visitor handouts at parking
areas below treeline on Trail Ridge Road. Its natural food is succulent
plant material and seeds, but many of the gregarious little animals are
becoming more or less dependent upon food offered them by humans. You
can see them most conveniently at Many Parks Curve.
Another little rodent, common in the lower meadows, is the RICHARDSON
GROUND SQUIRREL ("picket pin"). It lives in colonies, after the fashion
of the prairie dog of the plains. It is abundant in Moraine Park.
Relatively few park visitors see the BEAVER; but all can see examples of
its work. It works at night as a rule, and usually remains out of sight
when humans are abroad. These industrious rodents are much larger than
the related chipmunks and marmots, and weigh as much as 90 pounds.
Beaver pelts were part of the lure that led to the early exploration of
the West. Almost exterminated about 50 years ago, they are now
relatively abundant in Rocky Mountain National Park.
[Illustration: Yellowbelly marmot--seen by most visitors.]
The beaver is well adapted to its water environment. The hindlegs are
webbed for efficient swimming; the tail, broad and horizontally
flattened, helps in underwater maneuvering. However, its swimming speed
at the surface of the water is only about 2 miles per hour. Beaver can
remain submerged for over 5 minutes; this ability helps in escaping
enemies.
[Illustration: The beaver is sometimes seen by alert observers in
late afternoon or early morning.]
Beaver dams are abundant in the park. Many typical examples can be seen
in Horseshoe Park, Moraine Park, Glacier Basin, and Hidden Valley, and
along the Colorado River. Nearly all of the park trails pass beaver
workings. The dams are built of various materials in this region, but
most commonly of mud, parts of aspens, and debris. They are started from
the upstream side--usually on shallow creeks--and as the water level
rises so does the dam. The beaver uses its front paws almost as hands.
The load of mud or sticks sometimes is carried by being pressed against
the chest as the animal walks on its hind feet to the top of the
structure it is building. The dam is made to create a stabilized water
level. This is essential for protection of the beaver's island den--a
lodge made of sticks and mud. The beaver house starts as a solid heap of
debris, but the animal chews and digs out a couple of underwater
tunnels, as well as one or more dome-shaped rooms with the floor a few
inches above water level. In this dry retreat the beaver rests, sleeps,
and rears its family. Few natural enemies can pursue it through the
underwater entrances. Its food is chiefly aspen bark and twigs. A winter
supply is stored under water during late summer.
Because of its energy, skill, and persistence, the beaver has become a
symbol of industriousness. It is also often credited with more
intelligence than it probably possesses. Its apparent industry and
resourcefulness are due more likely to inherited instincts than to
reasoning. At any rate, this large rodent is surely one of the most
interesting animals in the park.
[Illustration: A narrow tail distinguishes the muskrat from the
beaver, which may live in the same locality.]
The MUSKRAT is frequently active in daylight hours. It lives in the same
environment as the beaver, but in the park has a much more limited
distribution and is confined to lower elevations. It builds lodges, too;
they are much smaller than those of the beaver, and are largely composed
of mud and plant material. The lodge serves as a secondary food source
in the winter, and many muskrat houses are practically eaten away by
spring. Unlike the beaver, a strict vegetarian, the muskrat eats fish,
insects, and any birds it can catch, as well as plant food. This animal
has not acquired the ability to build dams, but does make rafts of
sticks and twigs. When seen closely, a muskrat is easily distinguished
from a beaver, for it is smaller and has a slender, vertically flattened
tail, quite unlike that of the beaver.
Probably everyone recognizes the PORCUPINE. It is a large, short-legged
rodent, rather clumsy of behavior, and usually seen either sleeping or
leisurely chewing the bark of a tree. The porcupine survives, despite
its sluggish behavior, because of the protection afforded by some 30,000
quills in its pelage. Although it cannot "throw" these quills, they are
very loosely attached, and when the tail is vigorously thrashed about it
is inevitable that some of the quills become detached and fall away. The
unlucky recipient of such a slap of the tail will be convinced that the
quills were thrown, although the effective embedding of quills is done
by direct contact.
The MOUNTAIN COTTONTAIL is often seen in the lower forests. Despite
heavy predation by many natural enemies, the cottontail manages to
maintain itself because of its high birth rate. One mother may produce a
total of 25 young in the 4 or 5 litters born during the year. It is
fairly small, grayish-brown in color, with rather short ears and a
conspicuous cottony tail resembling a powder puff. It lives in
underground burrows and retains the same color winter and summer.
The SNOWSHOE HARE nests on the surface of the ground. Its fur changes
from grayish-brown in summer to white in winter. A denizen of the
spruce-fir and lodgepole pine forests and of the tundra, it hops about
the snow on its huge, furry, "snowshoe" feet, apparently finding the
severe winters of the high country no great hardship. It is not common
in the park, and therefore is not often seen.
[Illustration: Porcupine.]
[Illustration: Friendly chipmunks make themselves known throughout
the park.]
Motorists on the highest parts of the Trail Ridge Road often see the
PIKA, which looks like a small, grayish guinea pig but is really a close
relative of the rabbit. It is found in the rock slides and talus piles
in the high country mostly above treeline, and is seldom seen below
9,000 feet. Despite the subzero temperature of the tundra belt, it does
not hibernate. Its habit of storing little bundles of mountain grasses
and other alpine plants has given it the nickname of "alpine haymaker";
it is also sometimes called "cony"--a name better reserved for an
unrelated Old World mammal. Look for the pika at Rock Cut on Trail Ridge
Road, it seems to have favorite sunning spots from which it greets the
traveler with shrill shrieks.