Squirrel Watching in Denver: A Guide to 8 Species in Colorado’s Mile High City

squirrels in denver
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Denver’s diverse landscape, from urban parks to nearby mountain foothills, creates the perfect habitat for an impressive variety of squirrel species.

Whether you’re strolling through Washington Park or hiking in the foothills west of the city, you’ll encounter these fascinating rodents going about their daily activities of foraging, nesting, and preparing for Colorado’s changing seasons.

Understanding the different squirrel species in Denver enhances your outdoor experiences and helps you appreciate the rich wildlife diversity thriving alongside the Mile High City’s growing population.

From the familiar Eastern gray squirrels dominating city neighborhoods to the distinctive tufted-ear Abert’s squirrels in ponderosa pine forests, each species has adapted uniquely to Colorado’s elevation and climate challenges.

Pro Tip: Early morning and late afternoon offer the best squirrel watching opportunities, as these are peak activity times when squirrels are most actively foraging and moving between territories.

1. Eastern Gray Squirrel

Eastern Gray Squirrel - Different Types of Squirrels in Canada
by Fyn Kynd is licensed under CC BY 2.0

The Eastern gray squirrel (Sciurus carolinensis) represents Denver’s most common urban squirrel species, thriving in neighborhoods, parks, and anywhere mature trees provide shelter and food sources.

These adaptable medium-sized squirrels measure 9-12 inches in body length with equally long, bushy tails that serve as excellent balance tools during their acrobatic tree navigation.

You’ll recognize Eastern gray squirrels by their predominantly gray fur with white undersides, though color variations can include brownish tints and occasionally black phases.

Their large, prominent eyes and pointed ears make them easily distinguishable from ground-dwelling species. These squirrels demonstrate remarkable intelligence, remembering hundreds of buried nut locations throughout winter months.

Key Insight: Eastern gray squirrels can leap horizontally up to 10 feet between trees, making them incredibly efficient at navigating Denver’s urban canopy without touching the ground.

In Denver’s ecosystem, Eastern gray squirrels prefer oak, maple, and elm trees commonly found in established neighborhoods like Capitol Hill and Cherry Creek.

They’ve adapted well to human presence, often becoming quite bold around bird feeders and outdoor dining areas. Their diet consists primarily of nuts, seeds, fruits, and occasionally bird eggs, making them both beneficial seed dispersers and occasional garden visitors.

2. Fox Squirrel

Eastern Fox Squirrel
by acryptozoo is licensed under CC BY 2.0

The fox squirrel (Sciurus niger) stands as Denver’s largest tree squirrel species, easily identified by its impressive size and distinctive rusty-orange to reddish-brown coloration.

These robust squirrels can reach 10-15 inches in body length, with their characteristic bushy tails adding another 8-13 inches to their overall appearance.

Their size advantage helps them dominate feeding territories and access food sources other squirrels cannot reach.

Fox squirrels display remarkable color variation across Denver’s population, ranging from bright orange-red to deep brown, with some individuals showing gray phases similar to their Eastern gray cousins.

However, their larger size, more robust build, and often reddish-tinged fur make identification straightforward for observant wildlife watchers.

These intelligent animals demonstrate complex problem-solving abilities when accessing bird feeders and navigating urban obstacles.

Characteristic

Eastern Gray Squirrel

Fox Squirrel

Body Length

9-12 inches

10-15 inches

Weight

1-1.5 pounds

1.5-3 pounds

Primary Color

Gray with white belly

Rusty-orange to brown

Habitat Preference

Dense urban areas

Open woodlands, parks

These adaptable creatures thrive in Denver’s more open park settings and residential areas with scattered large trees.

Unlike Eastern gray squirrels that prefer dense canopy coverage, fox squirrels excel in environments with greater spacing between trees.

You’ll frequently spot them in City Park, Cheesman Park, and along the South Platte River corridor where mature cottonwoods provide ideal nesting sites.

3. Abert’s Squirrel

Abert's Squirrel
by Bandelier National Monument is licensed under CC BY-NC 2.0

The Abert’s squirrel (Sciurus aberti) represents one of Colorado’s most distinctive and specialized squirrel species, easily recognized by their prominent tufted ears and strong association with ponderosa pine ecosystems.

These medium-sized squirrels, measuring 10-11 inches in body length, display striking gray bodies with white undersides and distinctive black ear tufts that become more pronounced during winter months.

What makes Abert’s squirrels particularly fascinating is their highly specialized diet and habitat requirements. These Colorado natives depend almost exclusively on ponderosa pine trees for survival, feeding on inner bark, pine seeds, and fungi associated with pine root systems.

This specialization means you’ll primarily encounter them in Denver’s western foothills and mountain parks where ponderosa pine forests dominate the landscape.

Important Note: Abert’s squirrels rarely venture far from ponderosa pine forests, making them indicators of healthy pine ecosystems in the Denver mountain area.

Their unique ecological niche makes Abert’s squirrels excellent indicators of forest health in areas like Red Rocks Park and Mount Falcon.

Unlike the more adaptable urban squirrel species, Abert’s squirrels maintain strong territorial behaviors and rarely adapt to human-modified environments. Their presence signals intact ponderosa pine ecosystems that support diverse wildlife communities.

4. Red Squirrel

red squirrel (Tamiasciurus hudsonicus)
by Gilles Gonthier is licensed under CC BY 2.0

The red squirrel (Tamiasciurus hudsonicus) brings high-energy personality and fierce territorial behavior to Denver’s coniferous forest areas.

These small but mighty squirrels, measuring just 7-8 inches in body length, compensate for their size with aggressive defense of food caches and nesting territories.

Their reddish-brown summer coats and distinctive white belly patches make them easily identifiable among Colorado’s squirrel species.

Red squirrels demonstrate remarkable industriousness, creating extensive cone caches called “middens” that can contain thousands of pine and spruce cones.

These energetic foragers work tirelessly throughout summer and fall, harvesting and storing conifer seeds to sustain them through harsh mountain winters. Their chattering calls and scolding vocalizations often alert you to their presence long before visual identification.

In the Denver area, red squirrels primarily inhabit higher elevation coniferous forests in nearby mountain parks and foothills. They prefer dense stands of lodgepole pine, Engelmann spruce, and subalpine fir where cone production supports their intensive caching lifestyle.

Unlike squirrels in other regions, Colorado red squirrels must contend with extreme elevation changes and temperature variations that influence their behavioral patterns.

  • Highly territorial with distinct home ranges of 1-2 acres
  • Create multiple cone caches throughout their territory
  • Produce distinctive alarm calls when threatened
  • Active year-round, even during snowy conditions
  • Primary predators include martens, hawks, and owls

5. Rock Squirrel

Rock Squirrel
by Bandelier National Monument is licensed under CC BY-NC 2.0

The rock squirrel (Otospermophilus variegatus) represents Denver’s largest ground squirrel species and one of the most impressive rodent species in the region.

These substantial squirrels can reach 8-11 inches in body length with moderately bushy tails, displaying mottled gray-brown fur that provides excellent camouflage against rocky terrain and desert landscapes south and west of Denver.

Rock squirrels excel as both climbers and burrowers, demonstrating versatility that sets them apart from strictly arboreal or terrestrial species.

Their powerful claws and muscular build enable them to scale steep rock faces while also excavating complex burrow systems for shelter and food storage. These adaptable animals thrive in transitional zones where grasslands meet rocky outcrops and scattered vegetation.

Common Mistake: Many people confuse rock squirrels with prairie dogs due to their ground-dwelling habits, but rock squirrels are much smaller and have proportionally longer, bushier tails.

In Denver’s vicinity, rock squirrels inhabit areas like Chatfield State Park and the foothills regions where rocky terrain provides ideal denning sites.

Their omnivorous diet includes seeds, fruits, insects, and occasionally small vertebrates, making them important ecosystem contributors. They demonstrate fascinating social behaviors, often establishing loose colonies while maintaining individual territories within suitable habitat patches.

6. Golden-Mantled Ground Squirrel

golden-mantled ground squirrel (Callospermophilus lateralis)
by James St. John is licensed under CC BY 2.0

The golden-mantled ground squirrel (Callospermophilus lateralis) brings distinctive chipmunk-like appearance and mountain-adapted behaviors to Denver’s higher elevation areas.

These attractive squirrels, measuring 6-7 inches in body length, display striking golden-brown head and shoulder coloration contrasted with gray bodies and prominent white stripes bordered by black lines along their sides.

Despite their chipmunk-like appearance, golden-mantled ground squirrels are true ground squirrels with different behavioral patterns and habitat preferences.

They lack the facial stripes characteristic of chipmunks and demonstrate more extensive hibernation periods adapted to harsh mountain conditions.

These high-altitude specialists enter deep hibernation from October through April, requiring substantial fat reserves to survive extended dormancy periods.

You’ll encounter golden-mantled ground squirrels in Denver’s nearby mountain parks and recreational areas above 6,000 feet elevation.

They prefer open meadows, forest clearings, and rocky areas where diverse plant communities provide varied food sources.

Their diet emphasizes seeds, berries, and green vegetation, with seasonal timing crucial for accumulating winter survival resources. These squirrels often become quite bold around mountain campgrounds and picnic areas.

  1. Hibernate for 7-8 months annually in high-elevation habitats
  2. Cache food in multiple locations throughout their territory
  3. Prefer areas with rock piles or fallen logs for shelter
  4. Active during cooler parts of summer days
  5. Important prey species for mountain predators

7. Wyoming Ground Squirrel

Wyoming ground squirrel (Urocitellus elegans)
by Alex Stach is licensed under CC BY 4.0

The Wyoming ground squirrel (Urocitellus elegans) represents a less common but ecologically important species in Denver’s northern and eastern periphery areas.

These medium-sized ground squirrels, measuring 7-9 inches in body length, display subtle gray-brown coloration with lighter undersides and relatively short tails compared to tree squirrel species. Their streamlined appearance reflects adaptations for efficient burrowing and grassland navigation.

Wyoming ground squirrels demonstrate fascinating colonial behaviors, establishing extensive burrow networks that benefit multiple individuals and other wildlife species.

Their complex social structure includes sentinel behaviors where individuals watch for predators while others forage, creating cooperative survival strategies essential in open grassland environments where cover is limited.

These squirrels prefer shortgrass prairie and agricultural edge habitats found in areas like Rocky Mountain Arsenal National Wildlife Refuge and eastern plains locations near Denver.

They’ve adapted well to moderate grazing pressure and agricultural practices that maintain open grassland conditions. Their diet focuses on grasses, forbs, and seeds, with timing synchronized to peak vegetation growth periods in Colorado’s semi-arid climate.

Key Insight: Wyoming ground squirrels emerge from hibernation earlier than most ground squirrel species, taking advantage of brief spring growing seasons in high-altitude grasslands.

Conservation concerns for Wyoming ground squirrels center on habitat loss due to urban development and agricultural intensification.

Their dependence on native grassland ecosystems makes them vulnerable to landscape changes, highlighting the importance of preserving grassland habitats that support diverse wildlife communities in the Denver region.

8. Thirteen-Lined Ground Squirrel

Thirteen-lined Ground Squirrel - Types of Squirrels in the US
by Marit & Toomas Hinnosaar is licensed under CC BY 2.0

The thirteen-lined ground squirrel (Ictidomys tridecemlineatus) concludes our Denver area species guide with its distinctive striped pattern and grassland specialization.

These small ground squirrels, measuring 4-6 inches in body length, display remarkable camouflage through alternating light and dark stripes running lengthwise along their bodies, with the light stripes often containing rows of spots that create intricate patterns.

Thirteen-lined ground squirrels demonstrate remarkable adaptations for surviving in open grassland environments where predator pressure is intense and seasonal resources are limited.

Their extensive hibernation period can last up to eight months, requiring efficient fat storage and metabolic adjustments that allow survival through harsh Great Plains winters extending into Colorado’s eastern regions.

In Denver’s vicinity, these squirrels inhabit shortgrass prairie remnants, golf courses, and maintained grassland areas where their striped camouflage provides protection against aerial and terrestrial predators.

They prefer areas with scattered vegetation that provides both food resources and minimal cover for quick escape to burrow entrances. Their diet emphasizes insects, seeds, and green vegetation, with protein-rich insects particularly important during reproduction and growth periods.

Ground Squirrel Species

Habitat Preference

Elevation Range

Activity Period

Rock Squirrel

Rocky areas, canyons

4,000-7,000 feet

Year-round (limited winter)

Golden-mantled

Mountain meadows

6,000-11,000 feet

May-October

Wyoming

Grasslands, prairie

3,500-8,000 feet

March-October

Thirteen-lined

Short grass prairie

3,000-6,000 feet

April-October

Understanding the seasonal patterns and habitat requirements of thirteen-lined ground squirrels helps wildlife enthusiasts appreciate the complex ecological relationships supporting Denver’s diverse squirrel communities.

Their presence indicates healthy grassland ecosystems that support numerous other wildlife species adapted to Colorado’s challenging climate conditions.

Pro Tip: Look for small, evenly spaced holes in grassland areas – these are typically thirteen-lined ground squirrel burrow entrances, often with small mounds of excavated soil nearby.

Denver’s remarkable squirrel diversity reflects the city’s unique position at the intersection of Great Plains grasslands, riparian corridors, and Rocky Mountain foothills.

Each species has carved out specific ecological niches that allow multiple squirrel types to coexist across the metropolitan area’s varied landscapes.

From the urban-adapted Eastern gray and fox squirrels to the specialized mountain species like Abert’s squirrels, these important prey species support diverse predator communities while contributing essential ecosystem services through seed dispersal and soil aeration.

Whether you’re a longtime Colorado resident or new to the Mile High City, taking time to observe and identify these eight squirrel species enhances your connection to Denver’s natural heritage.

Consider visiting different habitats throughout the metro area – from downtown parks to mountain recreation areas – to experience the full spectrum of squirrel diversity that makes Denver such a remarkable place for wildlife observation.

Each species tells a story of adaptation, survival, and ecological interconnection that enriches our understanding of urban wildlife coexistence.

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