Many people wonder if squirrels create extensive underground tunnels, often due to concerns about garden or lawn damage. Understanding different squirrel types and their behaviors clarifies whether these common backyard visitors are indeed tunneling beneath the surface.
Tree Squirrels: Masters of the Canopy
The squirrels most frequently seen in residential areas, such as gray squirrels and fox squirrels, are primarily arboreal, meaning they live in trees. These tree squirrels construct nests, known as dreys, high in tree branches or within tree cavities. While they do engage in digging, their excavations are typically shallow and temporary.
Tree squirrels dig primarily to bury and retrieve food, like nuts and seeds, a behavior known as caching. These holes are usually small, often no more than an inch deep and about the size of a coin. They do not construct complex underground tunnel systems for habitation. Their reliance on trees for shelter and safety distinguishes them from other squirrel types.
Ground Squirrels: The True Diggers
Unlike their arboreal relatives, certain squirrel species are prolific burrowers. Ground squirrels spend the majority of their lives in extensive underground tunnel systems. Species like the California ground squirrel and the thirteen-lined ground squirrel are well-known for this behavior. Their burrows serve multiple purposes, including shelter, raising young, storing food, and escaping from predators.
Ground squirrel burrows can be elaborate, featuring multiple entrances and complex branching tunnels. For instance, California ground squirrel burrow systems can range from 5 to 30 feet long and typically lie 2 to 3 feet below the surface, though some can extend to 6 feet or more in depth. Entrances are usually about 4 inches in diameter. Thirteen-lined ground squirrels also create intricate burrows, often with an “L” shape just inside the entrance to deter predators.
Why Squirrels Dig: Beyond Just Tunnels
Digging is a fundamental behavior for all squirrels, driven by several motivations. A primary reason is food storage, particularly when food is abundant. Squirrels bury nuts and seeds to create caches, ensuring a supply for leaner times. This “scatter hoarding” means they hide food in numerous individual locations across their territory.
Squirrels also dig to retrieve previously buried food, though they do not always remember every hiding spot. Digging can also provide temporary refuge from adverse weather or serve as a quick escape from predators. Some squirrels may even dig shallow depressions to cool off in the soil on hot days.
Identifying the Digger: Squirrels vs. Other Animals
Distinguishing squirrel digging from that of other burrowing animals helps identify the culprit in a yard or garden. Tree squirrel holes are typically small, shallow, and often lack significant mounds of excavated soil around them.
These small holes are usually found scattered in areas where nuts or seeds might be buried, such as near trees or garden beds. In contrast, ground squirrel burrows feature larger, more noticeable entrances, often with visible mounds of dirt accumulated around them. These burrow systems are more extensive and permanent compared to the temporary holes dug by tree squirrels. Other common yard diggers include moles, which create raised ridges or tunnels just under the surface, and gophers, which produce crescent-shaped mounds with a plugged hole. Voles create very small, dime-sized holes, often near plant roots.