Iguanas, particularly the common Green Iguana (Iguana iguana), are well-known for their digging behavior. While these large reptiles are primarily arboreal, they regularly descend to the ground to excavate burrows. This activity is a necessary survival mechanism tied directly to their lifecycle and need for thermal regulation. The resulting holes are a clear sign of their presence in tropical and subtropical environments.
Primary Reasons for Burrowing
The primary motivation for an iguana to dig is reproduction. During the synchronized nesting season, female iguanas must locate suitable ground material to create a safe incubation site for their eggs. They seek out soft, loose soil, often in sandy areas, where they excavate a chamber to deposit their annual clutch. A single female Green Iguana can lay a substantial number of eggs, typically ranging from 20 to 70.
Beyond reproduction, burrows serve as protective shelter from environmental stresses and threats. As cold-blooded reptiles, iguanas rely on their surroundings for thermoregulation. A burrow provides insulation, offering a cool retreat from intense midday heat and a warmer sanctuary when temperatures drop. This shelter also offers a secure hiding spot from predators and a place to rest.
Characteristics of Iguana Burrows
Iguana burrows vary significantly depending on their purpose, but nesting tunnels can be quite extensive. Female iguanas excavate a main tunnel that extends deep into the soil to a final nesting chamber. While some burrows are reported to be six feet long and three feet deep, nesting tunnels can sometimes reach lengths of up to 70 feet with interconnected channels.
The entrance to a Green Iguana burrow often has a distinctive sideways “D” shape, usually with a noticeable pile of displaced soil outside the opening. These holes are frequently located in areas that offer structural support and soft digging material, such as under sidewalks, near tree roots, or beneath concrete slabs. The depth of the burrow is crucial for incubation, as the stable temperature within the soil helps the eggs develop over the 85 to 120-day period.
Species Differences in Digging Behavior
While the Green Iguana is the most common species associated with digging, burrowing behavior is not uniform across all iguanas. Green Iguanas are primarily arboreal and descend to the ground mainly for egg-laying, making their digging largely seasonal. Other species, however, are far more reliant on subterranean living throughout the year.
Rock Iguanas (Cyclura species), for instance, often depend on burrows and rock crevices for daily shelter. Similarly, the Spiny-tailed Iguanas (Ctenosaura species) are enthusiastic diggers, preferring to live within their burrows and creating complex, interconnected tunnel systems. This variation means some species dig only for nesting, while others use burrows constantly for shelter.
Managing Digging Behavior
Property owners can employ several non-lethal strategies to deter unwanted iguana digging by modifying the environment. Since iguanas seek out soft, loose soil for nesting, filling existing burrows with a mixture of soil and concrete or sand and gravel can prevent re-excavation. It is important to ensure no animals are inside the burrow before filling it.
To prevent new digging, physical barriers are effective, such as installing galvanized wire mesh or chicken wire fencing buried several inches below ground level. Habitat modification also involves removing potential attractants, like fallen fruit, and eliminating dense thickets or rock piles that provide easy shelter. Using motion-activated sprinklers can also startle iguanas, making the area less appealing for them to settle.