Pocket Gophers

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PEST NOTES Publication 7433University of California

Statewide Integrated Pest Management Program

Agriculture and Natural Resources

September 2009

Pocket gophers, often called gophers,

Thomomys species (Fig. 1), are burrow-ing rodents that get their name fromthe fur-lined, external cheek pouches,or pockets, they use for carrying foodand nesting materials. Pocket gophersare well equipped for a digging, tunnel-ing lifestyle with their powerfully builtforequarters; large-clawed front paws;ne, short fur that doesnt cake in wetsoils; small eyes and ears; and highlysensitive facial whiskers that assist withmoving about in the dark. A gopherslips also are unusually adapted for theirlifestyle; they can close them behind

their four large incisor teeth to keepdirt out of their mouths when usingtheir teeth for digging.

IDENTIFICATION

Five species of pocket gophers arefound in California, with Bottas pocketgopher, T.bottae, being most wide-spread. Depending on the species, theyare 6 to 10 inches long. For the mostpart, gophers remain underground intheir burrow system, although youllsometimes see them feeding at the edge

of an open burrow, pushing dirt out ofa burrow, or moving to a new area.

Mounds of fresh soil are the best signof a gophers presence. Gophers formmounds as they dig tunnels and pushthe loose dirt to the surface. Typi-cally mounds are crescent or horseshoeshaped when viewed from above (Fig.2). The hole, which is off to one side ofthe mound, usually is plugged. Molemounds (Fig. 3) are sometimes mistakenfor gopher mounds. Mole mounds, how-ever, are more circular and have a plug

in the middle that might not be distinct;in prole they are volcano-shaped. Un-like gophers, moles commonly burrowjust beneath the surface, leaving a raisedridge to mark their path.

One gopher can create several mounds

in a day. In nonirrigated areas, moundbuilding is most pronounced duringspring or fall when the soil is moist andeasy to dig. In irrigated areas such aslawns, ower beds, and gardens, dig-ging conditions usually are optimalyear round, and mounds can appear atany time. In snowy regions, gopherscreate burrows in the snow, resultingin long, earthen cores on the surfacewhen the snow melts.

BIOLOGY AND BEHAVIOR

Pocket gophers live in a burrow systemthat can cover an area that is 200 to2,000 square feet. The burrows are about

2 1/2 to 3 1/2 inches in diameter. Feed-ing burrows usually are 6 to 12 inchesbelow ground, and the nest and foodstorage chamber can be as deep as 6 feet.Gophers seal the openings to the bur-row system with earthen plugs. Short,sloping lateral tunnels connect the main

burrow system to the surface; gopherscreate these while pushing dirt to thesurface to construct the main tunnel.

Gophers dont hibernate and are activeyear-round, although you might notsee any fresh mounding. They also can

be active at all hours of the day.

Gophers usually live alone within theirburrow system, except when femalesare caring for their young or during

breeding season. Gopher densities canbe as high as 60 or more per acre inirrigated alfalfa elds or in vineyards.Gophers reach sexual maturity about1 year of age and can live up to 3 years.In nonirrigated areas, breeding usually

occurs in late winter and early spring,resulting in 1 litter per year; in irrigat-ed sites, gophers can produce up to 3litters per year. Litters usually average5 to 6 young.

Pocket gophers are herbivorous andfeed on a wide variety of vegetationbut generally prefer herbaceous plants,shrubs, and trees. Gophers use theirsense of smell to locate food. Most com-

monly they feed on roots and eshyportions of plants they encounter whiledigging. However, they sometimes feedaboveground, venturing only a bodylength or so from their tunnel opening.

Integrated Pest Management for Home Gardeners and Landscape Professionals

PocketGoPhers

Figure 1. Adult pocket gopher, Thomo-mys species.

Figure 3. Top view of a mole mound.

Figure 2 . Top view of a pocket gophermound.


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September 2009 Pocket Gophers

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Burrow openings used in this mannerare called feed holes. You can identifythem by the absence of a dirt moundand by a circular band of clipped veg-etation around the hole. Gophers alsowill pull entire plants into their tunnelfrom below. In snow-covered regions,gophers can feed on bark several feetup a tree by burrowing through thesnow.

DAMAGE

Pocket gophers often invade yards andgardens, feeding on many garden crops,ornamental plants, vines, shrubs, andtrees. A single gopher moving downa garden row can inict considerabledamage in a very short time. Gophersalso gnaw and damage plastic water

lines and lawn sprinkler systems. Theirtunnels can divert and carry off irriga-tion water, which leads to soil erosion.Mounds on lawns interfere with mow-ing equipment and ruin the aestheticsof well-kept turfgrass.

LEGAL STATUS

The California Fish and Game Codeclassies pocket gophers as nongamemammals. This means if you are theowner or tenant of the premises andyou nd pocket gophers that are injur-ing growing crops or other property,including garden and landscape plants,you can control them at any time andin any legal manner.

MANAGEMENT

To successfully control gophers, thesooner you detect their presence andtake control measures the better. Mostpeople control gophers in lawns, gar-dens, or small orchards by trappingand/or by using poison baits.

Probing for Burrows

Successful trapping or baiting dependson accurately locating the gophers main

burrow. To locate the burrow, you needto use a gopher probe (Fig. 4). Probesare commercially available, or you canconstruct one from a pipe and metal rod.Probes made from dowels or sticks workin soft soil but are difcult to use inhard or dry soils. An enlarged tip thatis wider than the shaft of the probe is an

important design feature that increasesthe ease of locating burrows.

To nd burrows, rst locate areas ofrecent gopher activity based on freshmounds of dark, moist soil. Fresh

mounds that are visible abovegroundare the plugged openings of lateraltunnels. You can nd the main burrowby probing about 8 to 12 inches fromthe plug side of the mound; it usuallyis located 6 to 12 inches deep. Whenthe probe penetrates the gophers bur-row, there will be a sudden, noticeabledrop of about 2 inches. You might haveto probe repeatedly to locate the go-phers main burrow, but your skill willimprove with experience. Because thegopher might not revisit lateral tunnels,trapping and baiting them is not assuccessful as in the main burrow.

Trapping

Trapping is a safe and effective methodfor controlling pocket gophers. Severaltypes and brands of gopher traps areavailable (Fig. 5). The most commontype is a two-pronged, pincher trapsuch as the Macabee, Cinch, or Gophi-nator, which the gopher triggers whenit pushes against a at, vertical pan.Another popular type is the choker-style box trap.

To set traps1, locate the main tunnelwith a probe, as described above. Usea shovel or garden trowel to openthe tunnel wide enough to set trapsin pairs facing opposite directions(Figs. 6 and 7). Placing traps with theiropenings facing in opposite directionsmeans you will be able to intercepta gopher coming from either end ofthe burrow. The box trap is easier touse if youve never set gopher trapsbefore, but setting it requires moresurface excavation than if you are us-

ing the pincer-type traps, an impor-tant consideration in lawns and somegardens. However, box traps can beespecially useful when the diameterof the gophers main tunnel is smallerthan 3 inches, because in order to use

1 See the online version of this Pest Note atwww.ipm.ucdavis.edu/PMG/PESTNOTES/pn7433.html to view a video on how to set aMacabee trap.

the pincer-type traps, you will need to

enlarge small tunnels to accommodatethem. This can add time to the trappingprocess.

It isnt necessary to bait a gopher trap,although some claim baiting mightgive better results. You can use lettuce,carrots, apples, alfalfa greens, or pea-nut butter as bait. Place the bait at the

back of a box trap behind the wire trig-ger or behind the at pan of a pincer-type trap. Wire your traps to stakes soyou can easily retrieve them from theburrow (Figs. 6 and 7).

After setting the traps, you can excludelight from the burrow by covering theopening with dirt clods, sod, canvasor landscape cloth, cardboard, or ply-wood. You can sift ne soil aroundthe edges of these covers to ensure alight-tight seal. Alternatively, you canleave the trap-sets uncovered, therebyencouraging gophers to visit these trap

Figure 4. A gopher probe.

Figure 5. Types and brands of gophertraps include (clockwise from upperright) Victor Black Box, Macabee, Go-phinator, and Cinch.


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sites as they seek out these openings toplug; gophers do not like open systems.

The inuence on capture success ofcovering versus uncovering trap-setsis unclear, although current data sug-gests there might be little difference.Leaving trap-sets uncovered will allowyou to set traps more quickly and checkthem more easily. However, you alwaysshould cover sets when using box traps,since gophers likely will plug tunnels

before hitting the trigger wire of thesetraps if you leave them uncovered.

Check traps often and reset whennecessary. If you havent captured agopher within 2 days, reset the traps ina different location.

Baiting with Toxic Baits

The key to an effective toxic baitingprogram is bait placement. Alwaysplace pocket gopher bait in the mainunderground tunnel, not the lateraltunnels. After locating the main gophertunnel with a probe, enlarge the open-ing by rotating the probe or inserting alarger rod or stick. Following label di-rections, place the bait carefully in theopening using a spoon or other suitableimplement that you use only for thatpurpose, taking care not to spill any

onto the ground. A funnel is useful forpreventing spillage.

Often, a back-lled (plugged) tun-nelone a gopher has lled with loosedirtwill feel similar to an activetunnel. Experience is required to tellthe difference. New probe users might

benet from digging down to conrmthat the tunnel is active or plugged. Ifit is an active tunnel, you can apply

bait to both of the tunnels sides beforeclosing it up. If it is plugged, dont treat.Once you are comfortable with your

ability to accurately determine activetunnels, you can follow the standard

baiting protocols described below.

Strychnine-treated grain is the mostcommon type of bait used for pocketgopher control. This bait generally con-tains 0.5% strychnine and is lethal witha single feeding. Baits containing 2.0%zinc phosphide are also available. As

with strychnine, these baits are lethalafter a single feeding.

Multiple feeding anticoagulants areavailable as well. When using anticoag-ulant baits, youll need to set out a largeamount of baitabout 10 times theamount needed when using strychninebaitsso enough will be available formultiple feedings. Although generallyless effective than strychnine baits, an-ticoagulant baits are less toxic. As such,they are preferred in areas where chil-dren and pets might be present. Whenusing either type of bait, be sure to fol-low all label directions and precautions.

After placing the bait in the maintunnel, close the probe hole with sod,rocks, or some other material thatexcludes light while preventing dirtfrom falling on the bait. Several baitplacements within a burrow systemwill increase success. Tamp down orclear existing mounds, so you can dis-tinguish new activity. If new moundsappear more than 2 days after strych-nine or zinc phosphide baiting or 7 to10 days after using anticoagulant baits,youll need to rebait or try trapping.

If gophers have infested a large area,use a hand-held bait applicator to

speed treatment. Bait applicators are acombination probe and bait reservoir.Once you have located a tunnel usingthe probe, a trigger releases a measuredamount of bait into the tunnel. Gener-ally, strychnine bait is used with suchan applicator, because it dispenses onlya small quantity of bait at a time.

Fumigation

Fumigation with smoke or gas car-tridges usually isnt effective, becausegophers quickly seal off their burrowwhen they detect smoke or gas. How-

ever, fumigation with aluminum phos-phide is effective at controlling gopherpopulations, although it is a restricted-use material. Applicators must becertied to use this material, whichcan limit homeowner use. Fortunately,many professional pest control opera-tors have access to aluminum phos-phide, so if trapping and baiting arenteffective, consider hiring a professional.

ExclusionUnderground fencing might be justi-ed for valuable ornamental shrubsor landscape trees. To protect existing

plantings, bury hardware cloth or 3/4-inch mesh poultry wire at least 2 feetdeep with an additional 6 inches ofmesh or wire bent at a 90-degree angleaway from the planting. This will helpkeep gophers from digging aroundthe fencing boundary. Also extend thefencing at least 1 foot aboveground todeter gophers moving overland. This

method is not perfect, however, be-cause persistent gophers can burrow

below the wire; also, the wire can re-strict and damage root growth of trees.

You can protect small areas such asower beds by complete undergroundscreening of the beds sides and bot-toms. When constructing raised veg-etable or ower beds, underlay the

Figure 6. Macabee traps in position.

Figure 7. When putting box traps inplace, cut the face of the hole smoothly,so you can push the traps tightly againstthe tunnels. You can cover the hole withlandscape fabric, corrugated cardboard,or other material to exclude light.


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soil with wire to exclude gophers. Toprotect individual plants, install wirebaskets, which you can make at homeor buy commercially, at the same timeyou are putting the plants into the

ground. If you use wire, use one thatis light gauge and only for shrubs andtrees that will need protection whileyoung. Leave enough room to allowfor the roots to grow. Galvanized wireprovides the longest-lasting protection.

Six to 8 inches of coarse gravel 1 inch ormore in diameter around undergroundsprinkler lines or utility cables also candeter gophers.

Natural Controls

Because no population will increaseindenitely, one alternative to a go-pher problem is to do nothing, lettingthe population limit itself. Experiencehas shown, however, that by the timegopher populations level off naturally,theyve already caused much damagearound homes and gardens.

Predatorsincluding owls, snakes, cats,dogs, and coyoteseat pocket gophers.Predators rarely remove every preyanimal but instead move on to hunt

at more protable locations. In addi-tion, gophers have defenses againstpredators. For example, they can es-cape snakes in their burrows by rapidlypushing up an earthen plug to blockthe snakes advance. Relying solely onnatural predators might not controlgophers to the desired level.

Some people have tried attracting barnowls to an area by installing nest boxes.Although barn owls prey on gophers,their habit of hunting over large areas,

often far from their nest boxes, andtheir tendency to hunt areas with abun-dant prey, make them unreliable forgopher control. When a single gopher,which is capable of causing damagerapidly, invades a yard or garden, agardener cant afford to wait for an owlto arrive. It is better to immediatelytake effective action, usually throughtrapping or baiting.

Habitat Modifcation

Reducing gopher food sources usingeither chemical or mechanical meth-ods can decrease the attractivenessof lawns and gardens to gophers. If

feasible, remove weedy areas adjacentto yards and gardens to create a bufferstrip of unsuitable habitat.

Other Control Methods

Pocket gophers easily can withstandnormal garden or home landscape ir-rigation, but you sometimes can useooding to force them from their bur-rows, which will enable you touse ashovel or a dog to destroy the rodent.

Gas explosive devices also are available

and are somewhat effective at control-ling gopher populations. These devicesignite a mixture of propane and oxygenin the burrow system. This concussiveforce kills the gopher and destroys theburrow system. Be sure to exercise cau-tion when using these devices becauseof the potential for unintended damageto property, injury to users and by-standers, potential for starting res indry environments, and destruction ofturf. Additionally, these devices can byquite loud, making them unsuitable in

residential areas.

No repellents currently are availablefor successfully protecting gardens orother plantings from pocket gophers.Plants such as gopher purge (Euphorbialathyrus), castor bean (Ricinuscommunis),and garlic have been suggested as re-pellents, but research has not substanti-ated these claims.

Although many devices designed tofrighten pocket gophers are commer-

cially availableincluding vibratingstakes, ultrasonic devices, and wind-powered pinwheelsthese rodentsdont frighten easily, probably becauseof their repeated exposure to noise andvibrations from sprinklers, lawnmow-ers, vehicles, and people moving about.Another ineffective control method isplacing chewing gum or laxatives inburrows in hopes of kill ing gophers.

Follow-up

Once you have controlled pocket go-phers, monitor the area on a regularbasis for reinfestation. Level all existingmounds after the control program, and

clean away weeds and garden debris,so you easily can see fresh mounds.

It is important to check regularly for re-infestation, because pocket gophers canmove in from other areas, and damagecan reoccur in a short time. If yourproperty borders wildlands, vacant lots,or other areas that serve as a sourceof gophers, you can expect gophers toreinvade regularly.

Be prepared to take immediate controlaction when they do. It is easier, cheap-

er, and less time consuming to controlone or two gophers than to wait untilthe population builds up to the pointwhere they cause excessive damage.

REFERENCES

Case, R. M., and B. A. Jasch. 1994. Pock-et gophers. In S. E. Hygnstrom, R. M.Timm, and G. E. Larson, eds.Prevention and Control of Wildlife Damage.Vol. 1. Lincoln: Univ. Neb. Coop. Ext.pp. B.1729.

Chase, J. D., W. E. Howard, and J. T.Roseberry. 1982. Pocket gophers. In J.A. Chapman and G. A. Feldhamer, eds.Wild Mammals of North America. Balti-more: Johns Hopkins Univ. Press. pp.239-255.

Ingles, L. G. 1965.Mammals of the PacicStates: California, Oregon, Washington.Stanford: Stanford Univ. Press. 506 pp.

Salmon, T. P., D. A. Whisson, and R. E.Marsh. 2006. Wildlife Pest Control aroundGardens and Homes. 2nd ed. Oakland:

Univ. Calif. Div. Agric. Nat. Res. Publ.21385. 122 pp. v


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AUTHORS:T. P. Salmon, UC Cooperative

Extension, San Diego Co.; and R. A. Bald-

win, UC Statewide IPM Program, Kearney

Agricultural Center, Parlier.

TECHNICAL EDITOR: M. L. Flint

EDITOR: M. L. Fayard

ILLUSTRATIONS:Figs. 1-2, J. K. Clark;

Fig. 3, L. L. Strand; Figs. 4 and 6, from

Wildlife Pest Control around Gardens and

Homes (Univ. Calif. Div. Agric. Nat. Res.

Publ. 21385); Fig. 5, R. A. Baldwin; Fig. 7,

from IPM for Stone Fruits (Univ. Calif. Div.

Agric. Nat. Res. Publ. 3389) and Wildlife

Pest Control around Gardens and Homes.

This and other Pest Notes are available at

www.ipm.ucdavis.edu.

For more information, contact the University of

California Cooperative Extension ofce in yourcounty. See your telephone directory for addresses

and phone numbers, or visit http://ucanr.org/ce.cfm.

University of California

Agriculture and Natural Resources Program

Produced by UC Statewide

Integrated Pest Management Program

University of California, Davis, CA 95616

University of California scientists and otherqualied professionals have anonymously peerreviewed this publication for technical accuracy. TheANR Associate Editor for Urban Pest Managementmanaged this review process.

To simplify information, trade names of productshave been used. No endorsement of named productsis intended, nor is criticism implied of similar productsthat are not mentioned.

This material is partially based upon worksupported by the Extension Service, U.S. Departmentof Agriculture, under special project Section 3(d),Integrated Pest Management.

WARNING ON THE USE OF CHEMICALSPesticides are poisonous. Always read and carefully follow all precautions and safety recommendations

given on the container label. Store all chemicals in the original, labeled containers in a locked cabinet or shed,away from food or feeds, and out of the reach of children, unauthorized persons, pets, and livestock.

Pesticides applied in your home and landscape can move and contaminate creeks, rivers, and oceans.Conne chemicals to the property being t reated. Avoid drift onto neighboring properties, especially gardenscontaining fruits or vegetables ready to be picked.

Do not place containers containing pesticide in the trash or pour pesticides down the sink or toilet. Either usethe pesticide according to the label, or take unwanted pesticides to a Household Hazardous Waste Collectionsite. Contact your county agricultural commissioner for additional information on safe container disposal andfor the location of the Household Hazardous Waste Collection site nearest you. Dispose of empty containersby following label directions. Never reuse or burn the containers or dispose of them in such a manner thatthey may contaminate water supplies or natural waterways.

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The University of California prohibits discrimination or harassment of any person on the basis of race,color, national origin, religion, sex, gender identity, pregnancy (including childbirth and medical conditionsrelated to pregnancy or childbirth), physical or mental disability, medical condition (cancer-related orgenetic characteristics), ancestry, marital status, age, sexual orientation, citizenship, or service in theuniformed services (as dened by the Uniformed Services Employment and Reemployment Rights Act of1994: service in the uniformed services includes membership, application for membership, performance ofservice, application for service, or obligation for service in the uniformed services) in any of its programsor activities.

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Equal Opportunity Director, University of California, Agriculture and Natural Resources, 1111 Franklin Street,6th Floor, Oakland, CA 94607, (510) 987-0096.

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