Moles and shrews are small mammals often mistaken for each other due to their reclusive, often subterranean lives and similar general appearance. These creatures, however, belong to distinctly separate biological orders and possess unique adaptations for their respective environments. Their differences become clear upon closer examination of their physical traits, behaviors, and ecological contributions.
Distinguishing Physical Characteristics
Moles, belonging to the family Talpidae, possess cylindrical bodies well-suited for their underground existence. Their velvety fur, which can range from dark gray to brown, has no particular direction to its nap, allowing them to move backward just as easily as forward through tunnels. Moles have very small, inconspicuous eyes that are often hidden within their fur, and most species lack external ears. The most striking feature of a mole is its large, paddle-like front paws, equipped with powerful claws that rotate outward, making them highly efficient digging tools. Their short, fleshy tails also assist in navigation within their burrows.
Shrews, classified under the family Soricidae, generally exhibit a more mouse-like appearance, though they are not rodents. They are among the smallest mammals. Shrews typically have prominent, pointed snouts with sensitive whiskers, small but visible eyes, and small, visible ears. Their tiny paws are unspecialized for digging, and their tails are often longer relative to their body size compared to moles, sometimes hairy.
Differences in dentition further separate these two groups. Moles tend to have fewer, sturdier teeth adapted for their diet. Shrews, in contrast, possess sharp, numerous, spike-like teeth that wear down over their lifetime, unlike the continuously growing teeth of rodents. Some shrew species have red-tipped teeth due an iron compound incorporated into their enamel, which is thought to make them more resistant to wear, especially on surfaces used for crushing and grinding.
Habitat, Diet, and Lifestyle
Moles are primarily subterranean creatures, spending nearly their entire lives constructing extensive networks of underground tunnels. These tunnel systems serve as both their habitat and their hunting grounds, with some eastern moles capable of digging a 160-foot burrow in a single night. Moles are insectivores, with their diet consisting mainly of earthworms, which can make up to 80% of their food intake, along with grubs and other soil-dwelling invertebrates. They can paralyze earthworms with their saliva and store them in underground “larders” for later consumption. Moles are generally solitary animals, only interacting for reproduction.
Shrews, while also insectivorous, typically inhabit the surface layers, foraging in leaf litter and dense vegetation, though they may use burrows abandoned by other animals or dig shallow ones. Their extremely high metabolic rates necessitate constant feeding, requiring them to consume 1.5 to 3 times their own body weight daily; they can only survive a few hours without food. Shrews eat a wide variety of invertebrates, including insects, spiders, slugs, and worms, and some species even prey on small vertebrates or consume seeds. Despite their small size, shrews are known for their aggressive and territorial nature.
Their primary environments reflect their physical adaptations, with moles being dedicated burrowers that rarely venture above ground, while shrews are more versatile ground-level foragers. Moles prefer loose, moist soil for digging, often found in grasslands, meadows, or woodlands. Shrews, conversely, are found in diverse habitats, including marshes, forests, and gardens, preferring areas with ample ground cover.
Ecological Roles
Moles play a significant role in maintaining soil health through their tunneling activities. Their continuous digging naturally aerates the soil, improving drainage and allowing water, air, and nutrients to penetrate deeper, which benefits plant growth. By consuming soil invertebrates like grubs and insect larvae, moles also contribute to natural pest control, helping to regulate populations that might otherwise harm plants. Their burrows can also create microhabitats, enriching underground biodiversity.
Shrews are important in controlling insect populations due to their voracious appetites and high consumption rates. Both moles and shrews serve as prey for various larger predators, including owls, hawks, and snakes, integrating them into the broader food chain.