At first glance, moles and shrews might look alike to the untrained eye, but they are very different mammals. There are seven species of moles and 33 different kinds of shrews in North America. Moles and shrews differ in their diets, size, habitat and features.
Moles are small mammals but still are significantly larger than shrews. Moles average around 7 inches in length and can weigh as much as 5 oz. in some species like the eastern mole. The largest shrews are in the 3- to 5-inch range and the heaviest shrew in the United States, the northern short-tailed variety, weighs just an ounce as an adult.
Moles possess obviously enlarged forefeet, turned into an outward position that looks like someone doing the breaststroke, according to the National Audubon Field Guide to Mammals. The front feet have long claws and webbing that enable the mole to dig as quickly as one foot per minute. The hind feet of moles are small and narrow. The feet of shrews are smaller than those of a mole and resemble the tiny and delicate feet of mice.
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The snout of a mole is flexible and naked, lacking hair, and it is an important sensory organ that can extend a half-inch past the mouth. Shrews have an elongated snout, but it has fur. The teeth of a mole are white, but those of the shrew are a chestnut color because of the presence of iron in the enamel.
Shrews live in varied habitats, with some living in deciduous forests, others in coniferous woodlands and still others in desert and watery environs. Shrews will live underground in some cases, but most make tunnels through the leaf litter where they live. Moles live underground all the time, with their surface ventures by accident and short-lived. Moles dig a series of tunnels and runways in search of food, with a central chamber den from which these tunnels radiate.
Moles and shrews are mainly insectivores, consuming a diet of insects, earthworms and other small creatures, although the shrew also is capable of killing and eating larger animals like birds and the young of rabbits. Both have five toes on each foot, thick but soft fur and small eyes. The soft fur lets them move forward and backward in tight quarters with ease. Their hearing is acute, with the ears of moles hidden beneath the fur to keep them clear of dirt and debris. Both have insatiable appetites, often consuming as much as 100 percent of their body weight in a 24-hour period.