Pocket Gophers

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Chordata
Class	Mammalia
Subclass	Theria
Order	Rodentia
Suborder	Myomorpha

Scientific Name

Geomyidae

Common Name

pocket gophers

Compiled by Whitney Cranshaw, Colorado State University:

Thomomys talpoides (Northern Pocket Gopher),
Geomys bursarius (Plains Pocket Gopher) and others

Hosts

All parts of many herbaceous and woody plants are fed on by pocket gophers. Pines, spruce, cottonwoods, shrubs and fruit trees are among the most-damaged woody plants.

Damage and Diagnosis

Pocket gopher damage.

The primary damage to woody plants is feeding on the roots. Pocket gophers are among the most damaging organisms to seedling tree plantings in many parts of the region, particularly on the plains. However, trees over 20 feet tall have been killed. The crowns of trees with gopher-caused root damage often first show foliage thinning, then foliage discoloration and finally, death. Root systems can be reduced to nubs.

The name “gopher” is at times incorrectly applied to most small mammals that live underground. The animals themselves, symptoms of their presence, and damage are often confused with moles, various voles and mice, prairie dogs, ground squirrels and kangaroo rats. In general, true pocket gophers are medium-sized (8 to 12 inches long), brown, plump rodents with short fur, short tails, large heads, small eyes, small ears and short, stout, front legs. Their name comes from external cheek pouches that open on either side of the mouth, used to transport soil. They live a burrowing existence and rarely are seen above ground. Their subterranean life style usually results in above-ground mounds of dirt that appear to have no entrance. This is because openings are typically plugged with soil. [Thus, mounds with conspicuous holes in them were made by something other than a pocket gopher.]

Life History and Habits

Gophers construct extensive burrow systems, with some of the tunnels being shallow and others more than 15 inches deep. A tunnel system may be linear or highly branched and can consist of up to 200 yards of tunnels. The tunnels are 2-3.5 inches in diameter. Entrances to the systems are marked by rather large mounds with plugged openings. Interestingly, soil castings (called “eskers”) from tunnels are also brought to the surface by means of the cheek pouches and stuffed into the snow. Following snow melt, the connected trails of soil making up an esker create a very characteristic pattern that roughly mirrors that of the underground tunnels. Gophers are ecologically important and influence soil formation, soil mixing, soil erosion, plant succession, rainfall infiltration, and the distribution of other animals. Each gopher brings at least one ton of soil to the surface each year. A single litter of 1-10 (usually 3-4) young is produced annually, usually in early summer. Roots and tubers make up most of the winter diet, while leaves and stems are the primary summer foods.

Management

Pocket gophers are not protected by federal or state laws but it should be recognized they can be environmentally valuable and control is difficult. Given these points, where tree damage is excessive, the following methods could be employed:

Mechanical Controls

Barriers have some use but to be effective must extend well below the soil line. Screen or plastic-mesh cylinders should be placed around trees to a depth of 18 inches. To avoid root damage on larger trees, this barrier should be placed 2 feet from the stem. Obviously, this is not always a practical method. Trapping is another method often used in larger infestation areas to reduce populations prior to poison baiting. Body-gripping traps (several types available) are placed within main or side tunnels by finding and excavating mound soil plugs. Traps should be checked frequently and moved if unsuccessful after a few days. Trapping works best in spring or fall when most tunnel construction occurs.

Repellents

While some experimental materials based on predator odors show promise, none of the highly-touted plant-based repellents (such as those utilizing castor-oil plant) as yet have any supporting data.

Chemical Control

Approved baits (strychnine alkaloid, zinc phosphide, chlorophacinone and diphacinone) are mixed with grain or formulated into paraffin blocks. [NOTE: some uses of these materials are “Restricted-Use”]. Baits are placed in tunnels by hand, by probe and spoon, or special bait-dispensing probe. Another larger machine called a burrow builder constructs artificial burrows and automatically baits them. The system works best if burrows are constructed in soil with moderate moisture and at depths typical of gophers using the area. The gophers intercept the artificial burrows and contact the bait. This is a tractor-pulled device and would be best-suited for economical treatment of large areas.

Detailed gopher management information is contained in Fact Sheet 6.515.

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.