Sciuridae (Squirrels and Chipmunks)

Sciuridae—the squirrel family—includes tree squirrels, chipmunks, flying squirrels, ground squirrels, and marmots. In Minnesota, these mammals range from canopy-dwelling climbers and woodland gliders to burrowers of open prairie and edges.

Despite that variety, sciurids share a recognizable foundation: a compact rodent build, strong forefeet used in food handling, and, in many species, an alert upright posture paired with quick, bounding movement. Their tails, ear shape, and posture often provide the fastest route to identification.

In the field, sciurids are often recognized by movement, silhouette, tail form, and habitat position—a red squirrel racing along a conifer limb, a chipmunk pausing with its tail low near a log, or a ground squirrel standing upright in short grass before vanishing into cover.

Orientation

These notes are organized by species, emphasizing comparison, posture, behavior, habitat, and field recognition rather than technical description alone.

General Characteristics

Body form: Compact to moderately elongated, usually with a strong hindquarter and agile forelimbs
Tail: Often prominent and useful for identification—bushy in tree squirrels, smaller in chipmunks, flattened in flying squirrels, and more restrained in some ground-dwelling species
Head and ears: Rounded head, large dark eye, and relatively small but often expressive ears
Posture: Frequently upright when alert or feeding, with the forepaws brought together to handle food
Movement: Climbing, bounding, gliding, or short dashing runs depending on habitat and lifestyle

Sciurids are among the most visible rodents because many spend time above ground or in low vegetation, often pausing long enough to show posture and behavior clearly.

Field Recognition

Sciurids are often identified by a combination of:

Tail shape: Full and arched, narrow and trailing, flattened, or only moderately bushy
Habitat position: High in the canopy, on trunks, along logs, in conifers, or in open grassy ground
Body proportions: Tree squirrel, chipmunk, flying squirrel, or marmot-like build
Movement: Branch-running, trunk spiraling, gliding, low scurrying, or upright scanning from the ground
Behavior: Food carrying, cone cutting, nut caching, chattering, or sudden freezing when watched

In many cases, posture and movement identify the animal before coat pattern does.

Species

Tamiasciurus hudsonicus

American Red Squirrel—a small, energetic conifer-associated squirrel with a rusty coat, pale underparts, and a strongly territorial, quick-moving presence.

Sciurus carolinensis

Eastern Gray Squirrel—a larger tree squirrel of hardwood woods, towns, and parks, usually recognized by its fuller build, long tail, and gray coat with pale underparts.

Sciurus niger

Fox Squirrel—a large warm-toned tree squirrel of more open woodland, edge, and developed landscapes, often longer-bodied and more rangy in appearance than the gray squirrel.

Tamias striatus

Eastern Chipmunk—a small ground-level squirrel with clear dorsal striping, a shorter tail, and a habit of pausing upright near logs, rocks, or brushy cover.

Neotamias minimus

Least Chipmunk—a smaller, paler chipmunk of drier or more open habitats, with striping but a more delicate overall impression than the eastern chipmunk.

Glaucomys sabrinus

Northern Flying Squirrel—a largely nocturnal woodland squirrel, broad-eyed and soft-furred, with a flattened outline and gliding membrane between fore and hind limbs.

Glaucomys volans

Southern Flying Squirrel—a smaller flying squirrel of wooded habitats, similar in structure to the northern species but generally more associated with deciduous and mixed forest.

Ictidomys tridecemlineatus

Thirteen-lined Ground Squirrel—a slim open-country species marked by striped and spotted patterning, often seen upright in short grass before dropping quickly into cover.

Poliocitellus franklinii

Franklin’s Ground Squirrel—a heavier-bodied ground squirrel of grassland and edge habitats, usually less crisply patterned and often glimpsed moving through taller vegetation.

Marmota monax

Woodchuck—a robust burrowing sciurid with a heavy body, short tail, and a low, deliberate gait, usually seen near field margins, openings, and roadside embankments.

Notes

Sciurids are often among the most approachable mammals to watch because they pause frequently while feeding, scanning, or handling food.
Tail carriage, body proportions, and where the animal is positioned in the habitat often narrow identification quickly.
Conifer woods, hardwood neighborhoods, prairie edges, and brushy openings each tend to favor different members of the family.

References

Minnesota Department of Natural Resources
https://www.dnr.state.mn.us
Animal Diversity Web
https://animaldiversity.org
iNaturalist
https://www.inaturalist.org