Jared Walker Smith - 2005 Environmental Studies Senior Seminar Research Project
St. Olaf College, Northfield, Minnesota

Deer Mouse - Peromyscus maniculatus

More deer mouse pictures
Description	A mouse with a total length around 152cm (138-168), and a tail length around 62cm (56-69). Back and sides are shades of brown, sometimes gray, and white below. The tail is distinctly bicolored, a dark upper surface and white under surface. The feet are white.
Status	The deer mouse is very common, ranging throughout North America.
Natural Role	The deer mouse is omnivorous, feeding primarily on seeds and insects, but also seeds, flowers, fruits and nuts. Because of its diet, it serves as an important seed disperser. Due to its abundance it is a very important prey species for a wide variety of predators. It is very disturbance adapted and is quick to colonize any exploitable habitat.
Agricultural Role	The deer mouse is the most common small mammal in almost any agricultural field (Stallman and Best, 1996; Sterner et al., 2003). In agroecosystems the deer mouse is very beneficial, consuming both weed and pest insect species. One study found that deer mice can consume up to 64% of the average annual weed seed production, and "can contribute significantly to control of black cutworms and corn earworms in cornfields" (Getz and Brighty, 1986). While tilled fields favors deer mice, they are usually still the most abundant small mammal in reduced tillage fields. Deer mice are reservoirs for the Hantavirus pulmonary syndrome, a potentially deadly virus. A distribution map, provided by the Center for Disease Control, is available here.

White-footed Mouse - Peromyscus leucopus

Compare white footed mouse to deer mouse
Description	The total length of the white-footed mouse is around 166cm (153-178), with a tail around 75cm (65-84). Similar in size and color to the deer mouse, the white-footed mouse generally has a shorter tail in comparison to body length (about 45% of the total length). The sides and back are generally a more reddish brown, and the tail is not sharply bicolored.
Status	The white-footed mouse is common west of the Rockies.
Natural Role	The white-footed mouse is omnivorous, primarily eating insects when abundant, but also seeds, nuts, berries, and grains. They can serve as important prey to many predators, including weasels, ground squirrels, and birds of prey.
Agricultural Role	White-footed mice are usually of little economic significance in agriculture, but are greater pests to forest reseeding projects. They may help keep insect pest species in check. White-footed mice, like deer mice, are reservoirs for the Hantavirus pulmonary syndrome, a potentially deadly virus. A distribution map, provided by the Center for Disease Control, is available here.

Western Harvest Mouse - Reithrodontomys megalotis

Meadow Vole - Microtus pennsylvanicus

Compare meadow vole to prairie vole
Description	The total length of the meadow vole is around 155cm (137-171), with a tail around 39cm (32-43), making it the largest vole (other than the muskrat) in Minnesota. It has a dark brown back with somewhat lighter sides, and its gray-brown belly is tipped with silver. Voles can be distinguished from mice by their short tails, hidden ears covered by hair, and less protrusive eyes.
Status	The meadow vole is very common throughout the central and northern United States, and is one of the most prevalent prairie species in the Cannon River Watershed.
Natural Role	Mostly herbaceous, the meadow vole primarily eats grasses, herbs, and sedges, although they will also eat seeds and occasionally tubers and bulbs. Meadow voles are a crucial prey species in Minnesota for most any carnivore. They help in the nutrient cycle through their large consumption of grass and can even aerate the soil (Neuburger, 1999).
Agricultural Role	The meadow vole can be a significant agricultural pest where abundant. Most high-intensity agricultural methods keep meadow vole populations in check in fields, as they rely on cover absent from tilled agriculture. The biggest effects will be around the edges of fields, as well as in reduced tilled agriculture and strip cropping (Peles et al., 1997; Basquill and Bondrup-Nielsen, 1999). Meadow voles will also prey on weed species, which can be beneficial to agriculture.

Prairie Vole - Microtus ochrogaster

Compare prairie vole to meadow vole
Description	The total length of the prairie vole is around 141cm (119-166), with a tail around 34cm (27-46). On average it is slightly smaller than the meadow vole, but should be distinguished by the distinct yellowish cast to the fur, especially on the belly. Also, female prairie voles have six teats compared with the eight in meadow voles.
Status	The prairie vole is a species of special concern in Minnesota, yet is more common in the southern regions of the Midwest.
Natural Role	Prairie voles are herbivores that feed primarily on grasses, but will also eat seeds. Where abundant they can serve as an important prey species, but they are too rare here to serve a vital role. In restored prairies, meadow voles often exclude prairie voles from colonizing.
Agricultural Role	Where abundant, prairie voles can be agricultural pests. Their natural habitat here, however, has been replaced with agricultural methods unsuited to them, such as high-intensity agriculture. If reduced till agriculture were adopted, this may help prairie vole populations recover, but it may also increase predation on crops (Getz and Brighty, 1986; Olson and Brewer, 2003).

Woodland Vole - Microtus pinetorum

Muskrat - Ondatra zibethicus

Description	The muskrat is a large aquatic vole, with a total length around 556cm (487-578) and a tail around 247cm (203-277). Its back and sides are brown, and the belly fur is silvery. It has large hind feet, and a long, black, vertically flattened tail.
Status	The muskrat is common throughout North America north of Mexico, and is very common in slow flowing or still waters in Minnesota.
Natural Role	Muskrats are primarily vegetarian, eating mostly green or aquatic vegetation. They will also eat bullheads and other vertebrates. Muskrats, where abundant, can be an important prey species, as well as controlling what type of vegetation is prolific.
Agricultural Role	When farms are near water, muskrats can be agricultural pests by eating corn and grain. Otherwise they have little agricultural significance.

Norway Rat - Rattus norvegicus - INVASIVE

Description	The Norway rat has a total length around 390cm (360-415), with a tail around 175cm (160-183). In the wild it is usually uniformly brown, and more rarely black. Captive individuals are often white. It has a long, tapering, scaly tale. It is much larger than any native Minnesotan mouse.
Status	The Norway rat is very common throughout the United States and Mexico wherever there are high concentrations of people, and is often found in agricultural areas.
Natural Role	This invasive rat competes and preys on native animals, but can serve as a food source for skunks and other carnivores. It is an omnivore that can eat most anything, and it also preys on insects, reptiles, birds, and small mammals. They can act as seed dispersers, however, and can aerate the soil with their burrows.
Agricultural Role	The Norway rat is an invasive species to North America, and does very well in artificial habitats - our cities, farms, and waste dumps. In these areas they are able to maintain high densities and causes more economic loss than any other mammal. They are carriers of disease and can contaminate food stores.

House Mouse - Mus musculus - INVASIVE

Description	The house mouse is smaller than the deer mouse, with a total length around 160cm (150-177) and a tail of 75cm (67-85). Wild individuals are generally a uniform grayish brown, and, unlike the deer mouse, they lack a bicolored tail. Their eyes are also less prominent than those of deer mice. Domestic species range in shades and colors, with laboratory strains often albino.
Status	The house mouse is very common throughout the United States and Mexico wherever there are high concentrations of people, and is often found in agricultural areas. In the more northern range it is more restricted to areas where people provide shelter.
Natural Role	This invasive mouse competes with native animals, but can serve as an important food source for other predators. This species is an omnivore and will eat practicly anything.
Agricultural Role	The house mouse is an invasive species to North America, and does very well in artificial habitats - our cities, farms, and waste dumps. It is second only to the Norway rat in food and property damage, and can contaminate food stores with its droppings. Despite all the damage they can do, house mice may help keep pest insect species in check, but the benefit is probably small (Brighty and Getz, 1986).

Meadow Jumping Mouse - Zapus hudsonius

Description	The meadow jumping mouse has a total length around 216cm (205-226), with a long tail around 131cm (122-135). It has the longest tail of any other mouse, and can easily be distinguished by this feature alone. The fur is yellowish brown to olive brown above, yellowish on the sides, and white bellow. The hind legs are larger and longer than the forelegs. While it can be confused with the woodland jumping mouse, that species is not found in the Cannon River Watershed.
Status	The meadow jumping mouse is much less common than the deer mouse in prairie habitats, and is fairly uncommon on tilled lands.
Natural Role	Meadow jumping mice are omnivores, eating seeds and fruits as well as insects and insect larvae, which can make up to one half of their diet in the spring. They are important prey to red-tailed hawks, weasels, foxes, and great horned owls.
Agricultural Role	Due to their relatively low numbers, the meadow jumping mouse probably does little damage to grain crops, and may actually help keep insect populations in check.

Plains Pocket Gopher - Geomys bursarius

Description	The plains pocket gopher has a total length around 260cm (239-300), with a tail around 66cm (54-75). This shiny brown, sometimes albino, rodent has large forelimbs with long, heavy claws, and small eyes and ears. It has prominent grooves on its upper incisors, but with close inspection it is most prominent by its external, fur-lined cheek pouches. Rarely seen above ground, the presence of pocket gophers is best detected by the series of closed mounds of loose soil, often spaced a meter or more apart, they leave with their passing.
Status	A common Minnesota mammal, the plains pocket gopher can be found throughout the Midwest.
Natural Role	The plains pocket gopher is primarily herbaceous, feeding on the underground root structures of plants, and sometimes pulling the entire plant underground to feed on it. They help aerate the soil with their extensive burrows and tunnels.
Agricultural Role	When abundant the pocket gopher can be a pest to agriculture, either by eating roots or leaving mounds. They also can be beneficial, however, by aerating the soil and preventing runoff of water.