Depending on where you are, the term “gopher” is applied to a variety of mammal species including ground squirrels, prairie dogs and moles. The true pocket gopher is actually very distinguishable once you recognize their appearance and sign, or indicators of the animal. Pocket gophers are burrowing rodents named for their external fur-lined cheek pouches. Unlike mole mounds, which have been characterized as miniature volcanoes, gopher mounds are fan-shaped in appearance. Pocket gophers are distributed throughout the Pacific Northwest, but occur more frequently in the drier climates of eastern Washington and Oregon

Arjo, Wendy M.

English

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
USDA National Wildlife Research Center - Staff 
Publications 
U.S. Department of Agriculture: Animal and 
Plant Health Inspection Service 
July 2003 
Is it a Pocket Gopher or Mole? 
Wendy M. Arjo 
National Wildlife Research Center’s Olympia Field Station 
Follow this and additional works at: https://digitalcommons.unl.edu/icwdm_usdanwrc 
 Part of the Environmental Sciences Commons 
Arjo, Wendy M., "Is it a Pocket Gopher or Mole?" (2003). USDA National Wildlife Research Center - Staff 
Publications. 195. 
https://digitalcommons.unl.edu/icwdm_usdanwrc/195 
This Article is brought to you for free and open access by the U.S. Department of Agriculture: Animal and Plant Health 
Inspection Service at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA 
National Wildlife Research Center - Staff Publications by an authorized administrator of DigitalCommons@University 
of Nebraska - Lincoln. 
BY WENDY M. ARJO
epending on where you are, the
term “gopher” is applied to a
variety of mammal species including
ground squirrels, prairie dogs and
moles.  The true pocket gopher is
actually very distinguishable once
you recognize their appearance and
sign, or indicators of the animal.
Pocket gophers are burrowing rodents
named for their external fur-lined
cheek pouches.  Unlike mole mounds,
which have been characterized as
miniature volcanoes, gopher mounds
are fan-shaped in appearance.  Pocket
gophers are distributed throughout
the Pacific Northwest, but occur more
frequently in the drier climates of
eastern Washington and Oregon.
Pocket gophers prefer roots and
stems of herbaceous annuals and
perennial plants that are often associ-
ated with early successional forests.
Because of this preference, seedlings
become a very tempting target to a
foraging pocket gopher.  Commonly,
gophers will prune seedling roots and
often pull the entire seedling into
their burrow.  Stem clipping at ground
level and girdling are also common
with seedlings less than half an inch
in diameter the most vulnerable.  In
deep snow conditions, aboveground
girdling of larger trees can occur.
Although aboveground girdling is
easy to detect, damage by pocket
gophers to root systems may go
unnoticed until seedlings become
discolored or tip over.  Several factors
have been noted that predispose a
stand to pocket gopher damage: 1)
current pocket gopher density; 2) soil
suitability for burrowing; 3) topogra-
phy; 4) herbaceous understory; 5)
amount of adjacent border with pre-
ferred forage; and 6) site preparation.  
Management practices to reduce
pocket gopher damage include silvi-
cultural practices, such as minimizing
disturbance of an area, habitat
manipulation, trapping, repellents,
fumigation and seedling barriers such
as Vexar tubing.  Strychnine baiting is
the most widely used method to
reduce pocket gopher populations
prior to planting seedlings.  Baits are
applied belowground to minimize
negative impacts on aboveground
non-target species; strychnine-baited
pocket gophers, however, may still
pose a threat to subterranean preda-
tors such as weasels.  In addition,
pocket gophers and other small
mammals using pocket gopher bur-
rows may consume the bait and die
aboveground.  
The Olympia Field Station has con-
ducted several tests to determine pri-
mary, secondary and tertiary risks
that may occur while strychnine-bait-
ing pocket gophers.  Population
responses of non-target species—
golden mantled ground squirrels and
yellow pine chipmunks—were moni-
tored on two reforested sites in
Oregon.  Immediately after baiting,
ground squirrel numbers declined;
however, the following spring the
population recovered.  Yellow pine
chipmunk populations were not
reduced by strychnine baiting, but in
fact increased in the treated plots the
following spring.  This increase may
reflect an invasion of chipmunks in
the absence of ground squirrels.    
Regardless of ground cover, pocket
gophers usually die belowground in
the nest or close to it.  This supports
the notion that fossorial (living below-
ground) rodents baited belowground
are unlikely to become secondary haz-
ards.  However, this does not entirely
eliminate the chance of an occasional
aboveground death or the potential
for underground predators like
weasels to encounter carcasses.
Predator-prey interactions are largely
unknown since subterranean predator
activity is difficult to observe.  
Artificial burrow systems were
established to investigate interactions
of weasels and pocket gophers at the
Olympia Field Station.  Weasels (80
Is it a Pocket Gopher or Mole?
D
Calculate after-tax timber
project returns!
PrettyÑEasyÑCheapÑReliable
For private forests:Ñ$49.95 + tax & ship
For Brochure:  FOREST ECON INC.
1150 Alturas, Suite 102, Moscow, ID 83843
Phone (208) 301-4634 ¥ Fax (208) 882-3317
forestecon@moscow.com ¥ www.treecents.com
EXCEL™-BASED TIMBER STAND
INVESTMENT ANALYSIS SOFTWARE
Burns & Williams
Lawyers
Ann Forest Burns
Bruce H. Williams
Business (206) 527-5942  •  Fax (206) 522-5392
5508-35th Ave. N.E., Suite 102  •  Seattle, WA 98105
E-mail: aforestburns@msn.com
12 WESTERN FORESTER  u JULY/AUGUST 2003
percent of those tested) readily killed
and consumed healthy pocket
gophers.  All weasels ate strychnine-
baited gopher carcasses after 72
hours, but no weasels died from sec-
ondary poisoning.  Although weasels
killed and cached gophers, caches
were composed of single animals
only.  Most of the weasels sampled,
but not entirely consumed, both
fresh-killed gophers and five-day-old
carcasses.  Although caching behavior
of weasels may increase their expo-
sure to secondary poisoning of
strychnine, this in turn may be mini-
mized by the fact that the majority of
weasels only sampled carcasses.  If
strychnine-baited pocket gophers die
aboveground, secondary hazards to
scavengers and tertiary hazards to
insectivores (species that eat insects
that cause decay of carcasses), may
occur. 
The fate of small mammal carcass-
es was determined on a study site in
the Rogue River National Forest.
Carcasses disappeared equally from
both scavengers and insects.  In addi-
tion, several insect species were sam-
pled to determine strychnine concen-
tration levels and any potential risks
to insectivore species.  Fly larvae and
ants were found to contain high levels
of strychnine; however, little risk is
posed to insectivores due to the
quantity of insects that would have to
be consumed to acquire a lethal dose.
Studies by the Olympia Field Station
have shown that controlling pocket
gopher populations with strychnine
baiting poses relatively little risk to
non-target species. u
Wendy M. Arjo is a research wildlife
biologist for the National Wildlife
Research Center’s Olympia Field
Station. She can be reached at 360-705-
4565 or wendy.m.arjo@aphis.usda.gov.
PHOTO COURTESY OF NWRC OLYMPIA FIELD STATION
Protecting seedlings from pocket gopher damage can be difficult since seedlings can be attacked from both
belowground and aboveground.
“Print Your Own Oregon 
Ownership Maps”
Atterbury Consultants, Inc. is selling tim-
berland ownership data in ArcReader Format
for the entire state of Oregon for $395.00.
This price includes ownership data for the top
30 timberland owners, sections, townships,
county boundaries, and several highways for
the entire state. It also includes a free copy of
ESRI’s ArcReader program which allows
users to print maps of the entire state or any
portion of it. Users pick the scale and which
layers to print.
• Designed for non-GIS people
• Very easy to use
• No GIS experience needed
Call Jon Aschenbach at 503-646-5393 for
more information. Download a full sized
brochure at www.atterbury.com.
ATTERBURY CONSULTANTS, INC.
3800 SW Cedar Hills Blvd., #190
Beaverton, OR 97005
WESTERN FORESTER  u JULY/AUGUST 2003  13


Is it a Pocket Gopher or Mole?

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USDA National Wildlife Research Center - Staff Publications U.S. Department of Agriculture: Animal and Plant Health Inspection Service July 2003 Is it a Pocket Gopher or Mole? Wendy M. Arjo National Wildlife Research Center’s Olympia Field Station Follow this and additional works at: https://digitalcommons.unl.edu/icwdm_usdanwrc  Part of the Environmental Sciences Commons Arjo, Wendy M., "Is it a Pocket Gopher or Mole?" (2003). USDA National Wildlife Research Center - Staff Publications. 195. https://digitalcommons.unl.edu/icwdm_usdanwrc/195 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Animal and Plant Health Inspection Service at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA National Wildlife Research Center - Staff Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. BY WENDY M. ARJOepending on where you are, theterm “gopher” is applied to avariety of mammal species includingground squirrels, prairie dogs andmoles.  The true pocket gopher isactually very distinguishable onceyou recognize their appearance andsign, or indicators of the animal.Pocket gophers are burrowing rodentsnamed for their external fur-linedcheek pouches.  Unlike mole mounds,which have been characterized asminiature volcanoes, gopher moundsare fan-shaped in appearance.  Pocketgophers are distributed throughoutthe Pacific Northwest, but occur morefrequently in the drier climates ofeastern Washington and Oregon.Pocket gophers prefer roots andstems of herbaceous annuals andperennial plants that are often associ-ated with early successional forests.Because of this preference, seedlingsbecome a very tempting target to aforaging pocket gopher.  Commonly,gophers will prune seedling roots andoften pull the entire seedling intotheir burrow.  Stem clipping at groundlevel and girdling are also commonwith seedlings less than half an inchin diameter the most vulnerable.  Indeep snow conditions, abovegroundgirdling of larger trees can occur.Although aboveground girdling iseasy to detect, damage by pocketgophers to root systems may gounnoticed until seedlings becomediscolored or tip over.  Several factorshave been noted that predispose astand to pocket gopher damage: 1)current pocket gopher density; 2) soilsuitability for burrowing; 3) topogra-phy; 4) herbaceous understory; 5)amount of adjacent border with pre-ferred forage; and 6) site preparation.  Management practices to reducepocket gopher damage include silvi-cultural practices, such as minimizingdisturbance of an area, habitatmanipulation, trapping, repellents,fumigation and seedling barriers suchas Vexar tubing.  Strychnine baiting isthe most widely used method toreduce pocket gopher populationsprior to planting seedlings.  Baits areapplied belowground to minimizenegative impacts on abovegroundnon-target species; strychnine-baitedpocket gophers, however, may stillpose a threat to subterranean preda-tors such as weasels.  In addition,pocket gophers and other smallmammals using pocket gopher bur-rows may consume the bait and dieaboveground.  The Olympia Field Station has con-ducted several tests to determine pri-mary, secondary and tertiary risksthat may occur while strychnine-bait-ing pocket gophers.  Populationresponses of non-target species—golden mantled ground squirrels andyellow pine chipmunks—were moni-tored on two reforested sites inOregon.  Immediately after baiting,ground squirrel numbers declined;however, the following spring thepopulation recovered.  Yellow pinechipmunk populations were notreduced by strychnine baiting, but infact increased in the treated plots thefollowing spring.  This increase mayreflect an invasion of chipmunks inthe absence of ground squirrels.    Regardless of ground cover, pocketgophers usually die belowground inthe nest or close to it.  This supportsthe notion that fossorial (living below-ground) rodents baited belowgroundare unlikely to become secondary haz-ards.  However, this does not entirelyeliminate the chance of an occasionalaboveground death or the potentialfor underground predators likeweasels to encounter carcasses.Predator-prey interactions are largelyunknown since subterranean predatoractivity is difficult to observe.  Artificial burrow systems wereestablished to investigate interactionsof weasels and pocket gophers at theOlympia Field Station.  Weasels (80Is it a Pocket Gopher or Mole?DCalculate after-tax timberproject returns!PrettyÑEasyÑCheapÑReliableFor private forests:Ñ$49.95 + tax & shipFor Brochure:  FOREST ECON INC.1150 Alturas, Suite 102, Moscow, ID 83843Phone (208) 301-4634 ¥ Fax (208) 882-3317forestecon@moscow.com ¥ www.treecents.comEXCEL™-BASED TIMBER STANDINVESTMENT ANALYSIS SOFTWAREBurns & WilliamsLawyersAnn Forest BurnsBruce H. WilliamsBusiness (206) 527-5942  •  Fax (206) 522-53925508-35th Ave. N.E., Suite 102  •  Seattle, WA 98105E-mail: aforestburns@msn.com12 WESTERN FORESTER  u JULY/AUGUST 2003percent of those tested) readily killedand consumed healthy pocketgophers.  All weasels ate strychnine-baited gopher carcasses after 72hours, but no weasels died from sec-ondary poisoning.  Although weaselskilled and cached gophers, cacheswere composed of single animalsonly.  Most of the weasels sampled,but not entirely consumed, bothfresh-killed gophers and five-day-oldcarcasses.  Although caching behaviorof weasels may increase their expo-sure to secondary poisoning ofstrychnine, this in turn may be mini-mized by the fact that the majority ofweasels only sampled carcasses.  Ifstrychnine-baited pocket gophers dieaboveground, secondary hazards toscavengers and tertiary hazards toinsectivores (species that eat insectsthat cause decay of carcasses), mayoccur. The fate of small mammal carcass-es was determined on a study site inthe Rogue River National Forest.Carcasses disappeared equally fromboth scavengers and insects.  In addi-tion, several insect species were sam-pled to determine strychnine concen-tration levels and any potential risksto insectivore species.  Fly larvae andants were found to contain high levelsof strychnine; however, little risk isposed to insectivores due to thequantity of insects that would have tobe consumed to acquire a lethal dose.Studies by the Olympia Field Stationhave shown that controlling pocketgopher populations with strychninebaiting poses relatively little risk tonon-target species. uWendy M. Arjo is a research wildlifebiologist for the National WildlifeResearch Center’s Olympia FieldStation. She can be reached at 360-705-4565 or wendy.m.arjo@aphis.usda.gov.PHOTO COURTESY OF NWRC OLYMPIA FIELD STATIONProtecting seedlings from pocket gopher damage can be difficult since seedlings can be attacked from bothbelowground and aboveground.“Print Your Own Oregon Ownership Maps”Atterbury Consultants, Inc. is selling tim-berland ownership data in ArcReader Formatfor the entire state of Oregon for $395.00.This price includes ownership data for the top30 timberland owners, sections, townships,county boundaries, and several highways forthe entire state. It also includes a free copy ofESRI’s ArcReader program which allowsusers to print maps of the entire state or anyportion of it. Users pick the scale and whichlayers to print.• Designed for non-GIS people• Very easy to use• No GIS experience neededCall Jon Aschenbach at 503-646-5393 formore information. Download a full sizedbrochure at www.atterbury.com.ATTERBURY CONSULTANTS, INC.3800 SW Cedar Hills Blvd., #190Beaverton, OR 97005WESTERN FORESTER  u JULY/AUGUST 2003  13

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Is it a Pocket Gopher or Mole?

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