What Animals Burrow in the Ground in Pennsylvania?

Pennsylvania, with its diverse landscapes ranging from dense forests and rolling hills to suburban lawns and agricultural fields, is home to a rich tapestry of wildlife. One fascinating aspect of this biodiversity is the number of animals that spend part of their lives underground. Burrowing animals play a crucial ecological role, aerating the soil, cycling nutrients, and creating habitats for other species. Understanding which animals create these subterranean networks offers insight into the hidden world beneath our feet.

In this comprehensive guide, we’ll explore the most common and significant burrowing animals in Pennsylvania, examining their behaviors, habitats, ecological impacts, and interactions with humans. Whether you’re a homeowner curious about holes in your yard, a nature enthusiast seeking to connect with local wildlife, or a student researching Pennsylvania’s fauna, this article will serve as an informative resource.

The Ecological Importance of Burrowing Animals

Before diving into the specific species, it’s important to appreciate why burrowing animals matter beyond their fleeting appearances above ground.

Soil Aeration and Fertility

One of the primary benefits burrowers provide is soil aeration. By digging tunnels, these animals loosen compacted earth, allowing oxygen, water, and nutrients to penetrate deeper into the ground. This process supports healthier plant growth and improves soil drainage—especially crucial in Pennsylvania’s humid continental climate, where heavy rains can lead to waterlogged surfaces.

Pest and Predator Control

Many burrowing mammals and reptiles feed on insects, grubs, and rodents. For example, the Eastern mole helps control lawn-damaging insect larvae. Conversely, predators like the eastern spotted skunk may use burrows to ambush prey, contributing to balanced ecosystems.

Habitat Creation

Abandoned burrows don’t simply vanish. They are frequently repurposed by other animals such as foxes, snakes, rabbits, or even songbirds seeking shelter. This ripple effect enhances biodiversity by providing homes for species that either can’t or don’t dig their own dens.

Influence on Plant Communities

By disturbing the soil and redistributing seeds during digging, burrowers can influence which plants take root in an area. This natural “tillage” promotes plant diversity essential for maintaining strong food webs.

Mammals That Dig and Dwell Beneath the Surface

Pennsylvania is home to several mammal species that either dig their own burrows or modify and occupy existing ones. These mammals range from the common to the elusive, each with unique adaptations for underground life.

Eastern Mole (Scalopus aquaticus)

The Eastern mole is perhaps the most ubiquitous and misunderstood subterranean mammal in Pennsylvania. Though often blamed for lawn damage, these animals are actually beneficial.

• Appearance: Small, velvety gray fur, paddle-like forelimbs, and nearly invisible eyes and ears.
• Habitat: Lawns, meadows, gardens—anywhere the soil is soft and insect-rich.
• Diet: Primarily earthworms, grubs, and insect larvae.
• Burrowing Behavior: Creates extensive networks of shallow feeding tunnels (visible as raised ridges) and deeper nesting chambers.

Moles are non-territorial and can tunnel up to 18 feet per hour. Contrary to popular belief, they rarely eat plant roots—damage to gardens is usually incidental or due to tunnel collapse.

Groundhog (Marmota monax)

Also known as the woodchuck, the groundhog is Pennsylvania’s largest burrowing rodent and famously associated with Groundhog Day in Punxsutawney.

Habitat and Range

Found in open fields, forest edges, and suburban areas, groundhogs dig extensive burrows with multiple entrances—sometimes exceeding 40 feet in length. Their dens usually feature separate chambers for nesting, sleeping, and waste disposal.

Seasonal Behavior

Groundhogs are true hibernators. During late fall, they seal themselves in their burrows and lower their body temperature and heart rate dramatically. Males emerge in early spring to establish territories and seek mates—a time when their burrow openings may first become visible.

Impact on Landscape

While their burrowing can erode banks or undermine foundations, groundhog tunnels help cycle soil and provide homes for displaced animals like rabbits and foxes. Their grazing behavior also keeps vegetation in check.

Eastern Cottontail Rabbit (Sylvilagus floridanus)

Though not prolific diggers, Eastern cottontail rabbits often use abandoned burrows, particularly those of groundhogs, for shelter. In some cases, they may modify existing tunnels or dig shallow scrapes lined with fur to protect their young.

Reproductive Behavior and Burrows

Females create nesting burrows—usually less than a foot deep—hidden under vegetation or within wooded edges. These nesting sites, or “forms,” are critical for protecting vulnerable young from predators and weather.

Striped Skunk (Mephitis mephitis)

The familiar black-and-white striped skunk is a capable digger and opportunist when it comes to underground shelter.

• Burrowing Behavior: Skunks may dig their own dens or take over those of other animals.
• Habitat: Wooded areas, under porches, sheds, and decks.
• Seasonal Use: Often hibernate in communal dens (with up to 12 individuals) during winter.

Skunks prefer dry, covered environments for their dens. Their digging often targets insect-rich soils, and they are known to create shallow pits while foraging for grubs.

Eastern Chipmunk (Tamias striatus)

Small, vocal, and highly active, chipmunks are masters of underground tunneling.

Tunnel Complexity

A typical chipmunk burrow system can span 20 to 30 feet and include several entrances, nesting chambers, and specialized food storage areas. These systems are usually located under logs, tree roots, or stone walls.

Foraging Habits

Chipmunks gather acorns, seeds, and berries which they store in cheek pouches and transport to underground caches. This behavior supports forest regeneration by dispersing seeds that eventually take root.

Reptiles and Amphibians That Use Burrows

While most reptiles and amphibians don’t create elaborate burrows, many rely on subterranean spaces for survival—especially during temperature extremes.

Eastern Garter Snake (Thamnophis sirtalis)

This common Pennsylvania snake often uses existing burrows—especially rodent tunnels or rock crevices—for shelter.

Overwintering Behavior

Garter snakes hibernate underground in communal dens, known as hibernacula, sometimes joining hundreds of others. Abandoned mammal burrows provide the necessary protection from freezing temperatures.

Ecological Contribution

Garter snakes feed on slugs, worms, and insects, making them valuable allies in gardens. They are non-venomous and generally harmless to humans.

Box Turtles (Terrapene carolina)

The Eastern box turtle doesn’t dig complex burrow systems, but it does excavate shallow depressions in the soil for sleeping and nesting.

Nesting Behavior

Females use their hind legs to dig nests in loose soil, usually in open, sunny areas. After laying eggs, they rebury the nest and leave, offering no parental care.

Thermal Regulation

During summer heat or winter cold, box turtles may partially bury themselves in leaf litter or shallow dug holes to regulate body temperature.

Frogs and Toads

Several amphibian species in Pennsylvania employ burrowing behaviors to survive seasonal temperature shifts.

Eastern American Toad (Anaxyrus americanus)

The Eastern American toad is a skilled digger. Using keratinized “spades” on its hind legs, it can rapidly excavate shallow burrows beneath leaf litter or loose soil. These burrows enable it to enter a state of brumation—similar to hibernation—during winter.

Wood Frog (Lithobates sylvaticus)

Wood frogs don’t dig traditional burrows but instead bury themselves under leaf litter and soil for insulation. Remarkably, they can survive being partially frozen during winter—an adaptation critical to their survival in Pennsylvania’s climate.

Insects and Invertebrates Living Underground

While typically overlooked, countless invertebrates make Pennsylvania’s soils their homes. Their burrowing activities have significant impacts on soil health and nutrient cycling.

Earthworms

Introduced earthworm species, such as the nightcrawler (Lumbricus terrestris), tunnel deep into the soil—sometimes over six feet. Native earthworms were largely eliminated by glaciers, so most earthworms now seen in PA are from Europe.

Soil Impact

Earthworms create vertical burrows that enhance drainage and nutrient distribution. However, they can also disrupt forest ecosystems by consuming leaf litter essential for native plants.

Cicadas

Periodical cicadas, particularly Brood X, which emerges every 17 years in parts of Pennsylvania, spend most of their lives underground.

Life Cycle

After hatching from eggs laid in tree branches, cicada nymphs drop to the ground and burrow in search of tree root sap. They remain underground for years, feeding and growing before emerging en masse.

Ecological Benefits

Their emergence provides a burst of nutrients when they die, fertilizing the soil. Their tunnels also increase aeration.

Ground-Nesting Bees

Approximately 70% of U.S. bee species are ground nesters, including various mining bees and sweat bees.

Nesting Strategy

These bees excavate individual tunnels in dry, sandy, or bare soil—common in gardens, meadows, and banks. Each female constructs her own brood cells, provisioning them with nectar and pollen.

Importance in Pollination

As essential pollinators, ground-nesting bees contribute greatly to ecosystem health and crop reproduction—underscoring the need to preserve their habitats.

Birds That Rely on Burrows

Though rare, a few bird species make use of underground nesting.

Barn Owl (Tyto alba)

The barn owl does not dig its own burrows, but in Pennsylvania, it may utilize ground-level cavities in banks, caves, or even the burrows abandoned by mammals.

Nesting Preferences

It prefers dark, sheltered spaces high off the ground, like barns or hollow trees. However, younger birds or displaced individuals may seek out lower, dug-out areas if traditional options are unavailable.

Signs of Burrowing Activity in Your Yard or Land

If you’ve noticed holes, mounds, or tunnels in your yard, it’s helpful to identify what species might be responsible. Here are common signs:

Understanding these signs can help distinguish between species and guide appropriate management decisions.

Managing Burrowing Wildlife on Your Property

While most burrowing animals are ecologically beneficial, conflicts can arise—particularly when burrows undermine foundations, damage lawns, or attract predators.

Humane and Effective Approaches

The Pennsylvania Game Commission recommends prioritizing coexistence over eradication. For example:

• Exclusion: Use wire mesh or fencing buried at least 12 inches deep to deter groundhogs and rabbits.
• Habitat Modification: Reduce mulch piles, seal foundation gaps, and trim vegetation near homes to make the environment less attractive to skunks and moles.
• Repellents: Some odor- and taste-based repellents may deter animals temporarily, though results vary.
• Professional Assistance: For persistent issues, licensed wildlife control operators can safely relocate animals.

Legal and Ethical Considerations

Certain animals, including groundhogs and rabbits, may be legally trapped or removed under specific conditions with permits. However, protected species such as box turtles and native snakes cannot be captured or relocated without authorization.

Important: Never attempt to handle or remove wildlife without proper training—especially skunks, which may carry rabies.

Appreciating Pennsylvania’s Underground Ecosystems

The world beneath Pennsylvania’s surface is alive with activity far beyond what we see during a walk in the woods or a mow around the backyard. From industrious moles to patient hibernating snakes, burrowing animals form an essential web of ecological services that support healthy soil, plant growth, and biodiversity.

These animals have evolved remarkable adaptations—specialized claws, low-light vision, or even freeze tolerance—allowing them to thrive in darkness. Their hidden lives remind us that nature’s complexity lies not only in majestic deer or soaring hawks but in the quiet rhythms of digging, nesting, and surviving below our feet.

What You Can Do to Support Them

• Preserve natural areas: Leave leaf litter, fallen logs, and open ground undisturbed in your yard.
• Avoid pesticides: Chemicals that kill grubs also remove food sources for moles and birds.
• Create wildlife corridors: Allow safe movement between habitats to reduce stress on burrowing species.
• Observe and learn: If you spot a burrow, take time to observe without disturbing it. You might even glimpse a rabbit peeking out or hear a chipmunk’s alarm call.

Final Thoughts

Pennsylvania’s burrowing animals are more than nuisances or curiosities—they are vital contributors to a balanced ecosystem. Whether you’re fascinated by the mysterious 17-year cicada cycles, concerned about a groundhog near your garden, or simply intrigued by the subtle signs of life beneath the soil, understanding these creatures enriches our connection to the natural world.

From the tiniest earthworm to the burly groundhog, each underground dweller plays a role in shaping the landscape we love. By learning about them, respecting their habitats, and coexisting humanely, we ensure that Pennsylvania’s subterranean wildlife remains a hidden treasure for generations to come.

What common mammals burrow in the ground in Pennsylvania?

Several mammals in Pennsylvania are known for their burrowing behavior, playing key roles in soil aeration and ecosystem dynamics. Among the most common are eastern moles, which create extensive tunnel systems while searching for earthworms and insects. While moles don’t technically eat plant roots, their tunneling can disrupt lawns and gardens. Another frequent burrower is the woodchuck, also known as a groundhog, which digs deep, complex burrows for shelter and hibernation. These burrows often have multiple entrances and can be several feet underground.

Cottontail rabbits and foxes also utilize burrows, though they typically rely on existing holes rather than digging their own extensive networks. Striped skunks dig dens under sheds, porches, or tree roots, especially when preparing to give birth or during winter. While less visible, shrews and voles create shallow runways beneath leaf litter or snow, sometimes connecting to larger tunnel systems. These burrowing mammals contribute to nutrient cycling and provide shelter for other species, although their activities can occasionally conflict with human landscaping efforts.

Are there reptiles in Pennsylvania that burrow into the ground?

While most reptiles in Pennsylvania do not actively dig deep burrows like mammals, several species use underground shelters for thermoregulation and protection. The common garter snake, for example, often utilizes existing burrows, rock crevices, or spaces under logs to hibernate during the winter months. These snakes may share communal dens, called hibernacula, with other individuals to survive cold temperatures. Similarly, the eastern hognose snake is known to burrow into loose, sandy soils with its upturned snout, especially when laying eggs or seeking refuge.

Box turtles, though primarily terrestrial, will dig shallow depressions in the soil to nest or to escape extreme heat. They use their hind legs to excavate nests for their eggs, selecting well-drained, sunny areas. While not true burrowers, these reptiles rely on the ground for critical life functions and often modify soil structure subtly through their nesting and sheltering behaviors. Their dependence on undisturbed ground highlights the importance of preserving natural habitats even in suburban areas.

Which insects in Pennsylvania are known for burrowing underground?

Numerous insect species in Pennsylvania create underground habitats, both during larval and adult stages. One notable example is the cicada, whose nymphs spend several years underground, feeding on tree root sap before emerging en masse to molt and reproduce. Periodical cicadas, like the 17-year Brood X, are especially famous for their long subterranean development. Ground beetles also spend part of their life cycle in burrows, hiding during the day and hunting at night for slugs and other pests.

Ants, particularly carpenter ants and field ants, build intricate underground colonies composed of chambers and tunnels. These nests can span several feet and house thousands of individuals. Similarly, yellow jackets construct subterranean nests in abandoned rodent burrows or in soil banks, expanding them annually by excavating dirt. Though often unnoticed, these insects aerate the soil, recycle nutrients, and serve as food sources for many animals. Their burrowing provides ecological benefits, even if their nests sometimes pose concerns near human dwellings.

Do amphibians in Pennsylvania burrow in the soil?

Yes, several amphibians native to Pennsylvania are adapted to burrowing, especially to avoid drying out and regulate body temperature. The eastern spadefoot toad is a prime example—named for the hardened, spade-like projection on its hind feet that enables it to dig backward into sandy or loose soils. This nocturnal species spends most of its time underground, only emerging after heavy rains to breed in temporary pools. It can remain buried for extended periods, waiting for ideal conditions.

Other amphibians, like some salamanders, also utilize burrows or natural soil cavities. The red-backed salamander, while not a digger, inhabits moist leaf litter and soil crevices, relying on existing spaces for shelter. The eastern tiger salamander breeds in ponds but lives in upland forests, often using abandoned mammal burrows for hiding. These amphibians contribute to soil health by controlling insect populations and serving as indicators of ecosystem integrity. Their underground habits make them elusive but ecologically vital.

Are ground-nesting birds in Pennsylvania considered burrowers?

While most birds in Pennsylvania don’t burrow in the traditional sense, a few species utilize or modify underground spaces for nesting and protection. The belted kingfisher is a notable exception, as it excavates long, sloping burrows in earthen riverbanks or gravel pits to lay its eggs. These tunnels can extend three to six feet into the soil and are often located near water sources where the bird hunts fish. The construction process involves the bird using its bill and feet to dig out the nesting chamber.

Other birds, like the horned lark, nest on the ground but do not excavate deep burrows. Instead, they rely on natural depressions or slight scrapes in the soil, often camouflaged with surrounding materials. These species are more prone to ground disturbance and habitat loss due to human activity. Although not true burrowers, their nesting behavior ties them closely to soil and ground conditions. Protecting natural landscapes and minimizing erosion is crucial for the survival of these ground-associated birds.

What role do burrowing animals play in Pennsylvania’s ecosystems?

Burrowing animals in Pennsylvania serve essential ecological functions, including soil aeration, nutrient cycling, and habitat creation. As they dig tunnels and move soil, earthworms, moles, and insects improve soil structure, allowing better water infiltration and root development for plants. Their activities help decompose organic matter and return nutrients to the soil. Additionally, abandoned burrows provide homes for other wildlife, such as snakes, frogs, and small mammals that do not dig their own shelters.

These animals also support food webs by serving as prey for predators like hawks, foxes, and snakes. Their foraging habits regulate populations of insects and other invertebrates, contributing to natural pest control. For example, ground beetles and moles consume large numbers of grubs and larvae that could otherwise damage vegetation. By modifying the physical environment, burrowers increase biodiversity and create microhabitats that benefit a wide range of species. Thus, despite occasional nuisance to humans, they are vital to healthy, functioning ecosystems.

How can homeowners manage burrowing animals on their property?

Homeowners in Pennsylvania may find burrowing animals disruptive to lawns, gardens, or foundations, but management should prioritize coexistence and humane solutions. First, identify the species responsible—moles leave raised ridges, woodchucks create large hole entrances with mounds, and skunks dig small conical holes while foraging. Once identified, consider non-lethal deterrents such as installing underground fencing, using repellents approved for the specific animal, or removing food sources like grubs or pet food.

For animals like groundhogs or skunks that take up residence under structures, exclusion methods should be employed cautiously, ensuring the animal isn’t trapped inside. It is often best to wait until young are independent before sealing entry points. Encouraging natural predators and maintaining a diverse yard with native plants can also reduce burrowing activity over time. In cases of persistent issues, consulting a licensed wildlife professional ensures ethical and effective resolution while respecting Pennsylvania’s wildlife regulations.