Florida’s landscape, dominated by deep, sandy soils, provides an ideal environment for subterranean life. Burrowing behavior serves multiple functions, primarily offering shelter from extreme heat and cold for temperature regulation. These underground structures are also used for reproduction, providing a safe space for nesting and raising young. Identifying the creator of a tunnel or hole is important for property owners and conservationists, as the animal’s identity dictates how the site should be managed.
The Protected Keystone Species
The most significant burrowing animal in Florida is the Gopher Tortoise, Gopherus polyphemus, which is protected as a threatened species by the state. This reptile is recognized as a keystone species because its extensive tunnels provide shelter for over 350 other animal species. The burrows offer refuge from predators, temperature extremes, and the frequent prescribed and natural fires common in Florida’s ecosystems.
A tortoise burrow is easily identified by its distinctive entrance, which is typically half-moon shaped with a flattened bottom, closely matching the curve of the tortoise’s shell. Directly outside the opening, a large mound of loose sand, known as the apron, accumulates from the tortoise’s constant digging and maintenance. These tunnels are much larger than those of any other Florida species, often averaging 15 feet long and 6.5 feet deep.
Disturbing a Gopher Tortoise or its burrow is prohibited under Florida law. This includes collapsing, damaging, or filling in the burrow, even if the tortoise is not currently visible inside. Land clearing or construction activities within 25 feet of a burrow require a permit from the Florida Fish and Wildlife Conservation Commission (FWC). This often involves the permitted relocation of the animal, ensuring the tortoise and the hundreds of species that depend on its shelter are not harmed.
Identifying Common Mammalian Diggers
Two common mammals are responsible for most noticeable digging activity, distinguished by the type of hole or mound they create. The Nine-banded Armadillo, Dasypus novemcinctus, is a non-native but naturalized species known for two types of excavations. As an insectivore, the armadillo digs numerous shallow, conical holes, typically only a few inches deep, as it forages for insects.
These animals also construct larger, more permanent burrows for shelter and nesting, which can be up to 7 feet deep and 20 feet long. Unlike the tortoise’s flat-bottomed entrance, an armadillo’s main burrow entrance is oval or round. It is often found concealed under dense vegetation, brush piles, or concrete foundations. A single armadillo may maintain an average of ten burrows within its home range.
The Southeastern Pocket Gopher, Geomys pinetis, presents a completely different sign of excavation. The pocket gopher is a solitary, strictly herbivorous rodent feeding on roots and tubers. It is found primarily in the deep, dry sandy soils of central and northern Florida. Its presence is marked by a distinctive fan-shaped mound of soil on the surface, earning it the local nickname “sandy mounder.” The entrance hole is almost always plugged with dirt, which differentiates it from the open entrances of other burrowing animals.
Smaller Subterranean Tunnels and Insect Holes
The Eastern Mole, Scalopus aquaticus, is an insectivore that creates two distinct types of subterranean paths. Moles are responsible for the raised, ridged tunnels visible just beneath the surface of a lawn or garden, which are shallow foraging runs as they hunt for earthworms and grubs. These runs feel spongy when stepped on and rarely have an open entrance.
The mole’s deeper living tunnels, which are 6 to 12 inches below the surface, result in small, conical or volcano-shaped mounds of soil pushed up onto the lawn. These molehills are generally smaller and more symmetrical than the large, fan-shaped mounds of a pocket gopher. Distinguishing mole activity from gopher activity is important, as moles do not typically eat plant roots, unlike the herbivorous pocket gopher.
Smaller holes, often dime-sized or slightly larger, are typically the work of invertebrates. The Cicada Killer Wasp, Sphecius speciosus, is a large, solitary wasp that digs burrows up to four feet deep to provision its young with paralyzed cicadas. The burrow entrance is a circular opening, often around a half-inch in diameter, surrounded by a small, distinct pile of excavated soil. Other tiny, circular holes can be created by Wolf Spiders or large beetles, but these are easily distinguished from the larger entrances created by Florida’s mammalian and reptilian burrowers.