The star-nosed mole, Condylura cristata, is a small, semi-aquatic mammal native to the moist, low-lying regions of eastern North America. It belongs to the family Talpidae, which includes other moles, but it is the only living member of its genus. This animal inhabits a range extending from eastern Canada down through the northeastern United States. While classified as a mole, its specialized biology and anatomy make it a unique creature in its environment.
Defining Physical Characteristics
The most defining physical trait of the star-nosed mole is the structure on its snout. This “star” is composed of 22 pink, fleshy, and mobile appendages that ring its nostrils. This organ is not for smelling but is a sensitive touch organ, packed with over 25,000 minute sensory receptors called Eimer’s organs. These receptors allow the mole, which is functionally blind, to render a detailed three-dimensional tactile image of its surroundings.
This specialized nasal structure enables the mole to detect and process sensory information with great speed. The brain of the star-nosed mole decides if an object is edible in as little as eight milliseconds. The appendages are in constant motion as the animal explores, and the two shortest tentacles have the highest density of sensory organs for final identification of prey.
Complementing its sensory star are physical adaptations for a subterranean lifestyle. The mole possesses heavily built forelimbs with broad, outward-facing feet and large claws designed for digging. Its body is stout and cylindrical, covered in dense, blackish-brown fur that is shorter and coarser than that of other moles.
Habitat and Foraging Behavior
Star-nosed moles prefer habitats with moist soil and poor drainage. They are found in coniferous and deciduous forests, wet meadows, marshes, and along the banks of streams and ponds. Their burrows are systems of shallow foraging tunnels that often have underwater entrances. The mole is active day and night and remains so in winter, when it can be found tunneling through snow and swimming in ice-covered streams.
It is considered the fastest-eating mammal, capable of finding and consuming prey in as little as 120 milliseconds. On land, it rapidly taps the ground with its star to locate small invertebrates. This strategy extends into the water, where it forages along the bottoms of streams and ponds for aquatic insects and annelids.
The mole has the ability to smell underwater. It achieves this by exhaling air bubbles onto objects or prey and then inhaling the bubbles back into its nostrils to process the scents. This behavior gives it an advantage in locating food in dark, murky environments. Its diet primarily consists of earthworms, aquatic insects, snails, and crustaceans, though it also consumes small fish and amphibians.
Unique Reproductive Cycle
The reproductive cycle is timed with the seasons, with pairing in autumn and births in spring. Mating occurs between mid-March and April. After a gestation period of approximately 45 days, the female gives birth to a single litter in a nest chamber of leaves and grass, placed in a dry location within the burrow.
A typical litter consists of two to seven young. The newborns are born blind, hairless, and with their star and eyes non-functional. Development is rapid; their eyes, ears, and the star’s sensory capabilities become functional at around two weeks of age. Weaning occurs after about three weeks, and the young reach sexual maturity at approximately 10 months.
Females produce one litter per year but may mate a second time if the first litter is lost. The mole’s long tail becomes swollen with fat storage during the winter. This may provide the energy needed for the demands of the breeding season.
Ecological Role and Status
Within its wetland ecosystem, the star-nosed mole serves as a link in the food web. As a consumer of a wide array of invertebrates, it helps regulate their populations. It is also a food source for various predators. Its burrowing activity provides soil aeration in the dense, wet ground it inhabits, which can benefit plant roots.
The International Union for Conservation of Nature (IUCN) lists the star-nosed mole as a species of “Least Concern,” as its populations are stable across its wide range. The primary threat to this species is habitat loss. The draining of wetlands and marshes for agriculture or development eliminates the environments the mole depends on for shelter and food.