Mar 30, 2008

Mountains Out of Molehills

Dr. Thomas Barnes thinks many people make “mountains out of molehills”…literally.  Dr. Barnes, University of Kentucky extension professor of forestry and wildlife specialist, finds moles fascinating.  “They are a perceived pest,” said Dr. Barnes.  “However moles have their place in the environment and they are beneficial.” 


The Eastern or Common Mole inhabits much of the Eastern United States.  Though many think they are rodents, they actually belong to the Order Insectivora (Insectivores) and are more closely related to shrews.  As the name suggests, they subsist primarily on insects.


Folks can go an entire lifetime without ever seeing a mole.  Rarely seen, their entire lives are spent below the surface.  They are well adapted for life underground.  They have little use for vision so they have only rudimentary eyes covered with a layer of skin and can probably only distinguish light.  Since external ears would interfere with life in soil, they have none; though they do hear and feel vibrations.  The tail is short and almost hairless and is used as a lever.  Their fur (moleskin) is plush and very soft to touch.  The fur will lay flat when stroked from either direction, offering no resistance as the mole moves forward and backward through its tunnels.  The hairless, cone-shaped muzzle is used for probing the soil for food. The nose is large when compared with the rest of the body.  Moles have a very keen sense of smell, allowing them to easily locate insect larvae.  Their sharp, conical teeth allow them to pierce shells of larvae.  Moles can easily breathe in oxygen-poor underground environments because they contain twice as much blood and hemoglobin as other mammals of similar size.  


A most distinguishing feature of the mole is its paddle-like front feet.  The feet are as broad as they are long, slightly webbed with large claws, and are disproportionately large when compared with other features.   They give moles a comical look.  They act like super-efficient shovels though, allowing moles to literally “swim” through the soil like Olympians. 


The Eastern Mole’s habitat includes woodlands, fields, meadows, and pastures in moist, well-drained soil.  They use two types of underground burrows; shallow surface runs are used for hunting insects, and a deep burrow is for protection and rearing of young.  Surface burrows are noted by the ridge of soil pushed to the surface as the mole “swims” through.  These burrows can be used repeatedly as highway systems.  As moles move through their surface tunnels they hunt primarily larval insects and earthworms.  Tunnels can be excavated at an amazing rate of 18 feet per hour.  Existing tunnels are traversed at a rate of about 80 feet per minute. 


Moles have voracious appetites and can eat close to their body weight daily.  A single mole will consume approximately 50 pounds of worms and insects annually.  With a lifespan of up to 3 years, a mole can consume up to 150 pounds of insects in a lifetime.


How are moles beneficial?  Moles are soil engineers.  “Moles aerate and loosen the soil,” explained Dr. Barnes.  “As they move through the soil, they break it up into small particles.  They also rid the soil of insect larvae.”  Moles can have a profound impact on their prey.  An Ohio State University Fact Sheet states “moles may control some insect outbreaks.”  Larval June beetles, often eaten by moles, feed on the roots of grasses and can completely destroy the sod in an area if not kept in check.   Furthermore, mole tunnels provide shelter, navigation routes, and hunting opportunities for other species of mammals.


The next time you’re inclined to assassinate the mole in your yard, think twice.  You may be killing your friend and propagating your enemy. 


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