The Strange Little Star-nosed Mole (Condylura cristata)

Strange.  Cryptic.  Uncommon.  Unique.  These are all words that could be used to describe the star-nosed mole.  The alien-looking structure on the end of its nose is known as an Eimer’s organ.  All 30 species of moles have this organ, but none have one that is as developed as the star-nosed mole’s.  The Eimer’s organ is used to detect prey in underground darkness and water, but scientists aren’t sure how it works.  Some think it senses tacticle stimulation, while others believe it senses the electrical fields of prey. It may sense both.  In any case over half of a star-nosed mole’s brain is used to process information gathered by its Eimer’s organ.

The star-nosed mole is a semi-aquatic subterranean mammal, living in meadows and woods adjacent to streams, ponds, and marshes.  They also occasionally occur in drier habitats.  Their underground tunnels often lead to water.  Incredibly, they can smell underwater by blowing a bubble that sticks to the end of their nose.  They are the fastest feeder on the planet, able to detect and consume prey in .2 seconds.  Scientists believe they evolved this rapid feeding mechanism and well developed Eimer’s organ to help them survive wet muddy environments where there is a dense population of small insects.  Star-nosed moles feed upon insects, worms, mussels, snails, crustaceans, salamanders, frogs, and fish.

Star-nosed mole.

Range map for the star-nosed mole.  This map doesn’t include Richmond, County Georgia where I reside.  Star-nosed moles do occur in east central Georgia.  My cat killed a specimen and left it on my back porch about 10 years ago.  They likely have a more extensive range than this map indicates but are rare and haven’t been reported in many areas of their range.

As far as I know, I am the only person to report the presence of star-nosed moles in Richmond County, Georgia.  According to the scientific literature and accepted range maps, star-nosed moles don’t occur in east central Georgia.  But about 10 years ago, a cat killed a star-nosed mole in my back yard.  My lot is on a sandhill plateau approximately 1/2 mile from a creek and wetland.  All other cat-killed moles in my yard were the much more common eastern mole ( Scalopus aquaticus ).  There is no chance of misidentification–the star nose is obvious.

Star-nosed moles may have been more widespread in southeastern North America during cool Ice Ages.  Over half of their present day range was under glacial ice then, and their range shifted south.  Pleistocene-aged remains of star-nosed moles have been excavated from caves in Arkansas and Missouri–far outside their present day range.  Cool moist stages of climate with low evapotranspiration rates supported more boggy environments favored by star-nosed moles.  However, it’s possible star-nosed moles still occur in those states but exist in cryptic populations yet to be discovered (or recognized and reported) because it is an uncommon animal that lives underground and is not often seen.

Video about the star-nosed mole.

Reference:

Catania, Kenneth

“A Nose that Looks Like a Hand and Acts Like an Eye: the Unusual Mechanism of the Star-nosed Mole”

Journal of Comparative Physiology 85 (4) 1999

Tags: Eimer's organ, star-nosed mole in Richmond County Georgia