Pocket Gophers

Geomys bursarius

Distribution

Pocket gophers are common and destructive rodents found throughout the agricultural zones of the prairies.

Appearance

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Adult pocket gopher.
Photo credit: Bob Gress, gpnc.org

Pocket gophers, commonly called moles, are burrowing rodents that feed on the roots of vegetation. Pocket gophers are greyish-brown in color with short legs and stout bodies. Their bodies are 12 to 15 cm long with a 6 cm nearly naked tail. They have large claws on the front feet and chisel-like front teeth, both ideal for digging and gnawing. Pocket gophers have small eyes set far apart and their ears are almost absent. Their lips close behind the teeth, allowing them to cut roots or dig burrows without getting soil in their mouth. They get their name from the fur-lined cheek pouches they use to carry food and nesting material.

Life Cycle

Pocket gophers spend most of their life underground. Each pocket gopher has its own extensive burrow system containing tunnels, a nest and a food storage area. A single pocket gopher burrow system may include as much as 240 metres of tunnels that are 6 to 12 cm in diameter. The feeding tunnels are generally 10 to 20 cm below the surface but nesting and food storage areas may extend 2.5 metres below the surface. They are active day and night throughout the year feeding on roots, tubers and the bulbs of plants, but will also feed on small fruit, seeds, and the leaves of forage and cereal crops. They are most active in the spring and fall when they collect food for storage. During winter and the heat of the summer they retire to the lower portions of their burrows. Pocket gophers are extremely unsociable and will fight one another upon meeting, except during the mating season. In the Prairies, mating occurs in May and June, with the young being born 30 to 40 days later. Pocket gophers have only one litter per year, with each litter containing 5 or 6 young. The young remain in the females burrow until mid August, at which time they wander overland and start their own, or locate an abandoned burrow system. Female life expectancy is 3 to 4 years, whereas males are considerably less.

Damage

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A typical gopher hole with a gopher peeking out.
Photo credit: garden-counselor-lawn-care.com

An infestation of pocket gophers can be first recognized by fan shaped mounds of soil on the surface, pushed out as the gophers excavate their tunnels. These mounds are generally 30 cm high by 30 to 50 cm in diameter. It has been estimated that a single pocket gopher can excavate approximately a ton of earth producing 30 to 50 mounds in one year. These mounds smother vegetation and result in rough terrain causing equipment damage. Feeding by pocket gophers can cause substantial losses to turf, gardens and field crops, especially alfalfa. In an alfalfa field an average pocket gopher population can be 50 gophers per hectare (20 per acre). Studies conducted show that this kind of population can consume approximately 1.8 kg (4 lbs) of vegetation per day.

Control

Attempting to control pocket gophers by gassing or drowning is generally ineffective. The most effective means of control is usually obtained by trapping or poisoning or a combination of both. For best results, trapping and poisoning should be conducted in the spring or fall when pocket gophers are most active.

Trapping

In yards, gardens, small fields or along shelterbelts control can be achieved with trapping. There are several types of traps that are presently available; "Victor" easy-set gopher trap, "Guardian" gopher trap, "Convert" gopher trap and "Blackhole" gopher trap. Specific instructions on setting traps and placement of traps are provided with the individual trap. For heavily infested areas trapping is too costly and labor intensive in comparison to poisoning.

Poison Baiting

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Pocket gopher tunnels visible above ground.
Photo credit: itsnature.org

The most effective poison for pocket gophers is strychnine. Baits pre-treated with strychnine are available commercially. The treated bait must be placed in the pocket gopher's main tunnel. This can be done by probing with a pointed stick or bar 15 to 45 cm back from the freshest mound. When the probe enters the tunnel it will drop sharply. The treated bait can then be dropped into the tunnel. The hole must then be closed or the gopher will plug that area of the tunnel with soil, without collecting the bait. A stone or clod of turf pressed firmly over the hole is generally sufficient. There is a hand probe called "Gopher Getter Jr.", which automatically dispenses poisonous bait into the pocket gopher tunnels. This type of probing and baiting is too time consuming whean large areas are heavily infested. For these areas mechanical burrow builders are most effective. Burrow builders are tractor drawn units that construct artificial burrows and at the same time automatically deposit small quantities of bait into these burrows. The pocket gopher's curiosity and laziness leads him to explore the artificial burrows thus encountering the poisonous bait. Burrow builders can often be rented from rural municipalities or local farm equipment and supply outlets.

"Gopher Getter" burrow builders, "Gopher Getter Jr.", various pocket gopher baits and traps may be purchased from local distributors such as farm equipment dealers or farm supply agencies. This list of equipment is not meant as an endorsement nor is it necessarily complete.

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