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Gophers

Life underground

Gophers are small rodents. Although the name is often used popularly to refer to a variety of animals, including snakes, in the United States gophers are the pocket gophers that live in the grasslands of western Canada, eastward to the Great Lakes, and down into northern South America. Pocket gophers (family Geomyidae) have fur-lined cheek pouches that let them carry food in large quantities. These rodents eat grain as well as underground roots, so a large population can do serious damage to farm fields.

Pocket gophers are burrowing animals with round little bodies without much visible neck. Their pouches, used only for carrying food, are located from the face back onto the shoulder region. They open on the outside, not into the mouth.

Gophers vary in size from only about 4 in (10 cm) to 14 in (35.5 cm) with a short, usually naked tail. They resemble small woodchucks, but they are not nearly as visible because they spend most of their lives underground. Their fur is colored varying shades of brown. It also occurs in varying lengths on a single animal because they continually molt, losing their hair in large patches.

The 25 species of gophers usually do not overlap very much in their ranges. The western pocket gophers (Thomomys) live all the way from sea level to perhaps an elevation of about 13,000 ft (3,965 m) in the mountains. Their gnawing teeth have a smooth front surface. The eastern species (Geomys) live in the flat plains and prairies of the southern states. Their gnawing teeth have a deep lengthwise groove, as does the third group of North American gophers, the yellow-faced pocket gophers (Pappogeomys). They are found only in a small region from Colorado down into Mexico. There are no pocket gophers in the northeastern section of the United States. In that area, the name gopher is often used for the chipmunk. Additional genera of pocket gophers live in Central America.


Gophers are well adapted to digging, with strong, large forearms and sharp claws. They have yellowish gnawing teeth that can keep digging even when their lips are closed, an aid in keeping the dirt out of their mouths while they dig. Also, they have special tear glands that continuously clean their eyes as they dig. Their ears can be closed against the dirt.

Gophers spend most of their lives underground. They dig shallow feeding tunnels that allow them to make their way to the juicy roots and tubers of crops and gardens. They also dig deeper tunnels in which they nest, rest, and store food. Their living tunnels are usually blocked at the end and are not noticeable from above except for a fan of earth that spreads out from where the opening would be. This fan may be as much as 6 in (15 cm) high.

These rodents do not hibernate, so their food stored during the summer must last them through the winter. They bring plant stems into their burrows in one of two ways. If remaining underground, they can eat the roots and then pull the plant stem down through the soil and carry it into their burrow. However, sometimes they go outside at night. Then they bite off plant stems and drag them back to their burrows. They also collect food in their cheek pouches. These externally opening pouches can be turned inside out for cleaning, after which a muscle pulls them back right-side-out again.

Gopher burrows do not support colonies of gophers. They are solitary animals, although so many of them can live so close to each other that they may seem to an observer to be part of a colony. This closeness allows them readily to find mates. A female takes a male into her own burrow for mating. He leaves and she remains to raise her litter. A female gives birth to four or five young usually only once each year, although some breed twice a year. The young are weaned and out on their own, digging their own burrows, within a month or two. Gophers rarely live more than two years.

When gophers are out of their burrows at night, they readily fall prey to owls and snakes. Their burrows may be dug up by foxes and coyotes. However, these small diggers may still be safe because they have the ability to run backward in their burrows almost as fast as they can move forward. Their sensitive tails are used in determining their direction.

Farmers tend to kill gophers because of the way they can destroy crops from the roots up. However, burrowing gophers keep the soil aerated and well-turned.

The southeastern pocket gopher (Geomys pinetis) of Florida, and coastal Georgia and Alabama is threatened with extinction. Its habitat has fallen prey to development.

See also Chipmunks.


Resources

Books

Caras, Roger A. North American Mammals: Fur-Bearing Animals of the United States and Canada. New York: Meredith Press, 1967.

Knight, Linsay. The Sierra Club Book of Small Mammals. San Francisco: Sierra Club Books for Children, 1993.


Jean F. Blashfield

Additional topics

Science EncyclopediaScience & Philosophy: Glucagon to Habitat