The Crestone Eagle, March 2006:
Small Wild Neighbors (Part 2 of 3)
In Part 2 of our study of small wildlife living in the Crestone area, we will examine squirrels, chipmunks, prairie dogs, marmots, beavers and gophers.
There are three types of squirrels, the ground squirrel, the flying squirrel and the tree squirrel.
In North America, there are several species that are regarded as tree squirrels. Tree squirrels are found around Crestone and throughout most of the US, other than the treeless Great Plains and Great Basin areas. They do not hibernate, and are active year round. You may not see them as often in the winter, since they stay in their nests to conserve body heat.
Colorado is home to three kinds of tree squirrels—fox (Sciurus niger), pine (Tamiasciurus hudsonicus), and the Abert’s squirrel (Sciurus aberti). The red fox squirrel is more common on the eastern plains and not seen in this area. Abert’s squirrel does live around here, a resident of ponderosa pine forests. The smaller, but noisier, pine squirrel, sometimes called a chickaree, occupies high timber and is also seen around Crestone. Abert’s and fox squirrels are about the same size (up to 20 inches long and 2 pounds in weight), although Abert’s has longer fur and therefore looks larger. The pine squirrel is much smaller—up to 14 inches long and weighing only about 9 ounces.
Every part of Colorado is home to at least one species of ground squirrel. On the grasslands of the eastern plains are the spotted ground squirrels (Spermophilus spilosoma). In the foothills and on western mesas and canyons lives the brown rock squirrel (Spermophilus variegates). The brownish gray Wyoming ground squirrel (Spermophilus elegans) lives in the mountains and sagebrush-covered basins. The white-tailed pronghorn squirrel (Ammospermophilus leucurus) lives in the hot desert shrub lands of the western valleys, while the golden-mantled ground squirrel (Spermophilus lateralis) lives throughout the mountains.
Squirrels use their tail for many things, with its primary function being for balance. This enables the squirrel to maneuver quickly without falling. It is also used as a parachute when the squirrel does fall, plus it acts as a blanket in the winter. Squirrels also use their tail to communicate with other squirrels. The most common tail gesture is the flicking which means get away!
Most squirrels eat nuts, seeds, grain, and fruit. When natural food is scarce, they will eat anything they can find, including all forms of human junk foods. They also eat mushrooms, plants, and bulbs that may be poisonous to humans. This is due in part to their very short digestive tract, making them able to handle these compounds.
On the ground, squirrels hop, moving twelve to twenty inches at a time, but they sometimes can cover up to six feet in one bound. Squirrels build nests called dreys, made of twigs and leaves. Their area is usually one to seven acres in size. They will find and store their food in this area and must keep other squirrels from invading this space.
Squirrels in captivity have lived to be twenty years old, yet most wild squirrels will die before their first birthday, due to being run over by vehicles. If they do survive autos, they should live five or six years.
Squirrels mate in the late winter or very early spring. Babies are born in the spring, without fur and blind, usually with four to a litter. They are called babies or infants while in the nest. For the first year they’re referred to as juveniles.
Chipmunks are rodents that live in forests, open woodlands, and brushy areas in North America. There are over twenty species of the chipmunk, and Colorado is home to five species. The most widespread is the least chipmunk (Tamias minimus), which lives over most of the central and western parts of the state. The Colorado chipmunk (Tamias quadrivittatus) lives in southern Colorado and northward along the foothills of the eastern slope. The Hopi chipmunk (Tamias rufus) lives on the Colorado plateau. The Uinta chipmunk (Tamias umbrinus) is a species of the central mountains. The cliff chipmunk (Tamias dorsalis) occurs in northwestern Colorado. They are not easy to distinguish from each other in the field. The larger ones are up to 9 inches long and weigh about 2 ounces.
Chipmunks are lively animals, active by day and tolerant of people. Like squirrels, they are known to become beggars at picnic grounds. Like all wild mammals, you should never feed them, as they get dependent on handouts. They do bite, and carry fleas that may carry diseases. Their native diet is seeds, berries, flowers and insects. Chipmunks have cheek pouches in which they carry food to store in their burrows. Food is stored for winter, and the animals usually do not come above ground while the snow covers the land above their home. They sleep for several days and then awake to feed, as their body does not store fat to sustain them like some deep hibernators. Some chipmunks dig extensive burrows which can be over 11 ft. long. These burrows often have more than one entrance and have chambers in which they store their winter food. Other chipmunks make nests in logs or in bushes.
Chipmunks resemble some species of squirrels, yet have peculiar characteristics that help to distinguish them. As a rule, the chipmunk is smaller in size and has prominent stripes on the head. They weigh from 1 to 5 ounces and are about 4 to 10 inches in length. Chipmunks make a sound that resembles those of birds. They tend to live for 2-4 years or more in the wild. They are hunted by hawks, snakes, foxes, coyotes, house cats and a few other animals.
Prairie dogs are found throughout most of the western United States, including Colorado. There are not too many of these critters here in Crestone, but according to Ron Rivele of the DOW, they are nearby.
As members of the genus Cynomys (Greek for “mouse dog”), all species of prairie dogs are related to ground squirrels, chipmunks and marmots. Of the five species of prairie dogs, three of their species call Colorado home:
Black-tailed prairie dog (C. ludovicianus), white-tailed prairie dog (C. leucurus), and the Gunnison’s prairie dog (C. gunnisoni).
Prairie dogs are fat robust rodents. They weigh 1 1/2 to 3 lbs. The head and body are 11 to 13 inches long, with a tail length of 3 to 4 inches. They are yellowish in color, with darker ears and a pale to whitish belly.
Prairie dogs have a high-pitched, bark-like call. Studies show that prairie dogs possess the most sophisticated of all natural animal languages. They apparently use different sounds to identify various predators, which include hawks, owls, eagles, ravens, coyotes, badgers and snakes. They can run up to 35 miles per hour for short distances. Prairie dogs only have one defense that works—raising the alarm and disappearing quickly.
Most of the prairie dogs found in Colorado hibernate during the winter. Their burrows are called towns. They have a social system composed of one male and several close-kin females plus their offspring. Their lifespan is 3-5 years in the wild, and have lived up to 8 1/2 years in captivity. Although they are almost exclusively vegetarian, nursing females have been observed both cannibalizing and communally nursing each other’s pups. They acquire all of their water from the food they eat.
One thing marmots (Sciurid) are good at is sleeping, with 80 percent of their time staying in their burrow. They are about the size of a house cat and all of them live in the northern hemisphere. They are the same as groundhogs, just not called that here in Colorado (mainly know as woodchucks in the southeast). They are a highly social species; in some cases offspring will live several years together with their parents and, in the case of alpine marmots, may even help rear younger siblings. When alarmed by predators (raptors, carnivores, and people) marmots whistle or chirp. These species specific vocalizations are referred to as alarm calls.
Of the six species of marmots found in North America, only yellow-bellied marmots (Marmota flaviventris) are common in Colorado and are the best studied of all marmot species. As high as the very top of Colorado’s 14’ers you will find the yellow-bellied marmot. As far as yellow-bellied marmots go, the males will disperse as yearlings and try to find one or more females. Females breed as 2 year olds. Litter sizes average is four pups.
Is it true that a marmot (groundhog) can predict how long the winter season will continue, depending on if it sees its shadow or not on February 2 of each year? Because of this silly belief, Groundhog Day is the only US holiday directly named after an animal!
Beavers (Castor Canadensis) are very common in Colorado and, yes, they are in our area too. Since they live in and around ponds and streams, we don’t see them right here in town, but we don’t have to wander too far to see them or the dams that they build.
Beavers are the largest of all rodents. They measure more than three feet in length, and weigh up to 55 pounds. They have a broad, flat tail and webbed feet. They feed on the upper, tender branches, leaves and bark of trees, but they do not eat the inner wood. Their den houses a nuclear family of parents, yearlings, and four or five kits. There is a single litter of young born each year following a four month gestation period.
You may not see them, but we have a lot of these critters here in Crestone. Who else do you think is digging all those holes outside of your house?
Gophers (Thomomys spp) are burrowing rodents that get their name from the fur-lined external cheek pouches, or pockets, that they use for carrying food. They are well equipped for digging tunnels, with powerful forequarters, large-clawed front paws and highly sensitive facial whiskers to assist movements in the dark. An unusual adaptation is the gopher’s lips, which can be closed behind the four large incisor teeth to keep dirt out of its mouth when it is using its teeth for digging.
Gophers range in length from 6 to 10 inches. They are seldom seen, although you might get lucky and see one feeding at the edge of an open burrow, or moving to a new area, but for the most part they remain underground in the burrow system. We know that they are around by the mounds and holes that they dig.
One gopher may create several mounds in a day. Here in Crestone, mound building is most pronounced during spring or fall when the soil is moist and easy to dig. Mounds are formed as the gopher digs its tunnel and pushes the loose dirt to the surface. The hole, which is off to one side of the mound, is usually plugged. Although mole mounds are sometimes mistaken for gopher mounds, it is easy to tell the two apart. Mole mounds appear circular, in profile they are volcano-shaped. There are no known moles residing here in Crestone. There is just one species of mole in Colorado, and it is restricted to the eastern plains.
Gophers live in a burrow system that can cover an area of 200 to 2,000 square feet. The burrows are about 2 1/2 to 3 1/2 inches in diameter. Feeding burrows are usually 6 to 12 inches below ground, whereas the nest and food storage chamber may be as deep as 6 feet. Short, sloping lateral tunnels connect the main burrow system to the surface and are created during construction of the main tunnel for pushing dirt to the surface.
Gophers do not hibernate and are active year-round. They can be active at all hours of the day. Gophers usually live alone within their burrow system, except females with young or when they are breeding. They can live up to 3 years. Females produce one to three litters per year, with five to six young.
Gophers are herbivorous. They feed on a wide variety of vegetation. They use their sense of smell to locate food. Most commonly they feed on roots and fleshy portions of plants they encounter while digging. Sometimes they feed above ground, venturing only a body length or so from their tunnel opening. Burrow openings used in this manner are called “feed holes.” They are identified by the absence of a dirt mound and a circular band of clipped vegetation around the hole. Gophers will also pull entire plants into their tunnel.
That does it for part 2 on small wildlife. For Part 3, which will be covered in the next Eagle, we will take a look at the different snakes around our area.