by Crystal Cockman
One species that is so unique in appearance that if you spot one, there will be no question that is what you’ve found, is the star-nosed mole (Condylura cristata). Their nostrils are ringed by 22 rays, or fleshy tentacles, which possess more than 25,000-minute sensory receptors, known as Eimer’s organs. They can touch 10 or 12 different places in a single second. Their star-nose is believed to help the animal forage for small prey. It can also use it to detect seismic wave vibrations.
With each touch 100,000 nerve fibers send information to the mole’s brain – that’s five times more touch sensors than the human hand, in one nose that’s smaller than a fingertip. They have perhaps the best sense of touch of any mammal. The star may also be able to detect faint electrical signals from aquatic prey. If true, star-nosed moles and the platypus (Ornithorhynchus anatinus) are the only mammals known to possess this ability.
They are native to eastern North America. A report in the journal Nature calls this species the world’s fastest eater – they can eat a worm or insect in 120 milliseconds. Its brain decides in 8 milliseconds whether a prey is edible or not.
The star-nosed mole has thick, blackish-brown fur that is water repellent and large scaled feet with large claws, and a long, thick tail. During the winter, the tail swells to 3 to 4 times it’s normal diameter and is believed to store fat needed for the colder months. It is functionally blind, and relies on its nose and sense of touch to detect prey. They eat small invertebrates, aquatic insects, worms, mollusks, small amphibians and small fish. Predators include hawks, owls, foxes, weasels, minks, skunks, bullfrogs, and large fish such as the northern pike and largemouth bass, as well as domestic cats.
The star-nosed mole is the only mole species out of 39 species that lives in swamps and marshes. The mole is not limited to underground tunnels, but can easily swim and forage for food in lakes and streams. It is one of only two mammals that can smell underwater, by blowing air bubbles and sucking them back into its nose. The other mammal that can smell underwater is the water shrew.
Molecules in the mole’s star-nose turn physical signals of touch into electrical signals in the nervous system, and since many of these molecules are also found in people, more knowledge about these may lead to new treatments for pain.
They are active both day and night and do not hibernate in winter. They are more social than other moles in eastern North America and are believed to form small, loose colonies of related individuals. However, we do not know if moles share a network of tunnels, other than a paired male and female during the breeding season.
Star-nosed moles have an important role in the ecosystem. They provide food for a number of carnivores and are a ravenous predator of aquatic invertebrates. By tunneling through moist ground, star-nosed moles provide oxygen to the roots of plants that might otherwise be trapped in compacted soil with no oxygen.
Star-nosed moles are relatively common, but since they inhabit poorly drained areas with marsh-like habitat, they are not often found near humans. Destruction of wetland environments negatively affects this species.