Star-nosed moles are small mammals, measuring roughly 7 inches and weighing just 1 1/2 ounces. Like other moles, they spend much of their lives underground, although this species is actually semi-aquatic. They can be found in parts of Canada and the United States, though they're rarely seen as they live mostly in tunnels in damp soil, usually adjacent to water. They have several evolutionary adaptations that help them survive in their habitat.
The most notable feature, and probably the greatest adaptation, of star-nosed moles is the nose. They have 22 retractable tentacles surrounding their noses in a bilaterally symmetrical ring formation. These tentacles aren't just for show, they contain more than 25,000 receptive organs that can pick up the electrical impulses given off by the moles' prey, which includes worms, leeches, insects, larvae, molluscs and small fish. This helps members of the species to find their prey with ease. In fact, they can locate and devour their prey in just 230 milliseconds.
Star-nosed moles have shovel-like feet that are extremely large in comparison to their size. This adaptation allows them to dig their tunnels more quickly and effectively. They can excavate roughly 7 to 8 feet of soil in an hour. The further they travel underground, the more food they're likely to come across. These large feet also help them when it comes to swimming, as they act much like paddles.
Since star-nosed moles live the majority of their lives underground, in the dark, they have no need for good eyesight. Over years of evolution, their eyes have adapted so they're comparatively small, when you consider the eyes of similarly sized mammals, and don't work very well. Smaller eyes mean they're less likely to get filled with soil and injured or irritated. What their eyes lack in clarity of vision, they make up for with their noses.
Star-nosed moles who live near water hunt for roughly 75 to 85 percent of their food underwater. They have tunnels with an exit at or below the surface of the water and spend a lot of time swimming around, searching for prey. One adaptation that helps them when it comes to spending time underwater is their fur, which has evolved to withstand water so it's easier for them to get dry when they return to their tunnels.
- SUNY College of Environmental Science and Forestry: Star-Nosed Mole
- Animal Place: Star-Nosed Mole Facts
- Cornell University: Adaptations of Small Mammals
- BBC Nature: Star-Nosed Mole
- Vanderbilt University: Marsh Dwelling Moles Gives New Meaning to the Term "Fast Food"
- Animal Diversity Web: Condylura Cristata