Rodents

Rodents are some of the smallest and least seen animals in the park, but they play a vital role in maintaining a healthy ecosystem.

 

Common Rodents at Lake Roosevelt

 

Beaver

NPS/Claire Abendroth

American Beaver

Castor canadensis

• The largest rodent in North America, averaging 30–60 pounds and 35–40 inches long, including tail

• Semi-aquatic mammals with webbed hind feet, large incisor teeth, and a broad, flat, scaly tail

• Builds dams to create the pond habitats that supports the willow and ash trees they prefer as winter food and building material for their lodges

• Live in family groups, called colonies, which can have between 2–14 members

 

Columbian ground squirrel

Photo by David Restivo

Columbia Ground Squirrel

Spermophilus columbianus

• Fur on upperpart of body is a mottled brown-gray, while underpart is a cinnamon-buff color; facial fur is bronze across the bridge of the nose

• Can grow 12–16 inches in length, including a 3–4 inch tail

• Lives in open habitats such as grasslands, meadows, shrub-steppe and semideserts

• Feeds on roots, bulbs, stems, leaves, flowers, seeds, and fruits

• Social animals, living in large colonies of related females; mature males leave the colony to live among groups of females that are not related to them

• Hibernates in underground borrows for up to 70% of the year

 

Northern flying squirrel

NPS Photo

Northern Flying Squirrel

Glaucomys sabrinus

• Glides between trees using membranes of furred skin between forelegs to hindlegs to catch the air

• Fur is light brown on the back and light grey on the belly and feet

• Diet consists of lichens, fungi, berries, seeds, and eggs

• Found primarily in coniferous mountain forests

• Rarely spotted due to their nocturnal habits

 

Porcupine

NPS/Alex VanDerStuyf

Porcupine

Erethizon dorsatum

• Average adult is 20–25 pounds and 25–36 inches long

• Fur is brownish-yellow to black with white or yellow quills

• Uses quills as defense against predators

• Excellent tree-climbers

• Diet consists of a wide variety of plant material depending on seasonal availability, including berries, grasses, stems, evergreen needles and the inner bark of a tree

 

Yellow-pine chipmunk

NPS Photo

Yellow-pine Chipmunk

Tamias amoenus

• Common in the park

• Wide range of habitat from meadows to coniferous forests

• Can be tawny to cinnamon in color, with three dark and two light stripes on the face, and five dark and four light stripes on the back

• Eats berries, nuts, seeds, grasses, mushrooms, and occasionally insects

 

Yellow-bellied marmot

NPS Photo

Yellow-bellied Marmot

Marmota flaviventris

• Average adult is 20–28 inches long and 3.5–11 pounds

• Reddish-brown upper body, yellowish belly, small ears, and prominent tail

• Found in open grassy communities and almost always near rocks

• Feeds on grasses and forbs, seeds, and occasionally insects, depending on seasonal availability

• Hibernates during winter months