The family Talpidae, which includes all true moles, consists of small insectivorous mammals adapted for a life almost entirely beneath the soil surface. These animals are known for their powerful, spade-like forelimbs and dense, velvety fur that facilitates subterranean movement. Their presence is dependent on specific environmental conditions, raising questions about their ability to exist in the diverse, often arid, landscapes of the Southwestern United States. Determining their distribution in Arizona requires examining local ecology.
The Presence of True Moles in Arizona
The question of true moles existing in Arizona has a clear answer: they are generally absent from the state’s fauna. Surveys of the state’s mammalian populations do not include any species from the Talpidae family. While some North American moles range westward to California and into cooler, wetter climates, they do not extend their range into the desert and semi-arid regions of Arizona. The lack of suitable habitat prevents them from establishing a permanent presence.
The closest members of the Talpidae family come to Arizona is the extreme southwestern United States, primarily in riparian or higher-elevation zones. For residents encountering subterranean damage, the cause is virtually never a true mole. This absence is strongly influenced by the environmental conditions that define the state’s geography, making it an inhospitable place for mole biology.
Common Misidentification: Arizona’s Look-Alike Subterranean Pests
The animals most frequently mistaken for moles in Arizona are Pocket Gophers, particularly the Valley Pocket Gopher (Thomomys bottae), which is common across the state. Pocket gophers are burrowing rodents, not insectivores like moles, and are identified by several morphological features. They possess large, fur-lined external cheek pouches for carrying food and prominent incisor teeth. Unlike the mole’s horizontal, surface-level mounds, gophers create fan-shaped or crescent-shaped mounds of dirt when pushing soil out of their tunnels. These mounds typically have a plugged entrance hole, as gophers quickly seal their tunnels against predators.
Voles, small rodents sometimes called meadow mice, also cause confusion. Voles create above-ground runways and use shallow tunnels, causing damage to plant roots and bark at the base of trees. Unlike gophers and moles, voles have visible eyes and ears, and their feeding damage focuses on plant material. Pocket gophers are vegetarians, feeding on roots, bulbs, and tubers, while moles feed almost exclusively on invertebrate prey. The type of damage—chewed roots versus disturbed soil from insect foraging—can help identify the actual culprit.
Ecological Factors That Limit Mole Habitats
The primary environmental restrictions preventing mole establishment in Arizona are soil composition and aridity. Moles depend on moist, loose, and loamy soils that are easy to tunnel through for their foraging networks. Much of the soil in Arizona’s desert and valley areas contains a high concentration of caliche, a hardened layer of calcium carbonate that forms a natural cement beneath the surface. This material makes the deep, continuous burrowing required by moles nearly impossible.
The arid climate also limits the availability of the mole’s primary food source. Moles are insectivores whose diet consists largely of earthworms and grubs, which thrive in moist, organically rich soil. Low annual precipitation and high evaporation rates mean earthworms are scarce, and the soil dries out quickly. Without consistent moisture to maintain tunnel integrity and support invertebrate prey, the energetic cost of survival is too high for moles to sustain viable populations.
Managing Subterranean Pests in Arizona Landscapes
The most effective strategy for managing the subterranean pests present in Arizona, primarily pocket gophers, is lethal trapping. Gophers are not protected under Arizona law and can be controlled freely on private property, with trapping being the most consistently effective method for eliminating individuals.
Trapping Techniques
Traps should be placed directly into the main underground runway, which can be located using a probe to find the main tunnel entrance indicated by a fresh mound. For maximum effectiveness, two traps are typically set facing opposite directions within the main tunnel system, ensuring the gopher is caught regardless of its travel direction. It is important to completely cover the opened tunnel after setting the traps to block light and air drafts. Gophers are triggered to push soil and plug the opening when they detect a breach. Trapping is most successful in the spring and fall when gophers are highly active and pushing up fresh mounds.
Exclusion and Repellents
Exclusion is another viable management technique, particularly for protecting high-value plants or garden beds. Barriers made of galvanized hardware cloth, with a mesh size of one-half inch or smaller, can be used to line raised beds or surround the root balls of individual trees. This barrier needs to extend at least 18 inches deep to prevent gophers from tunneling underneath. While sonic devices or herbal repellents are marketed for gopher control, university studies consistently show these methods to be largely ineffective at deterring the pests.