Southeastern Pocket Gopher
SOUTHEASTERN POCKET GOPHER
Photo Credit: Roger Birkhead
SCIENTIFIC NAME: Geomys pinetis Rafinesque
OTHER NAMES: Salamander, Sandy Mounder.
DESCRIPTION: A medium-sized (length, males approx. 290 mm [11.6 in.]; females approx. 261 mm [10.4 in.]), burrowing rodent (Dunn 1997). Four males collected from Georgia ranged from 145 to 208 grams (5.1-7.3 ounces), with nine females ranging from 135 to 138 grams (4.7-4.8 ounces) (Whitaker and Hamilton 1998). Dorsum, medium to cinnamon brown, tinged reddish orange along the flanks and shoulders. Ventral surfaces light gray to buff brown. Forearms, throat, and tail pale white to buff (Dunn 1997, Whitaker and Hamilton 1998). Body stout and cylindrical with reduced eyes and ears, and strongly developed forelimbs with elongated claws (Pembleton and Williams 1978). Tail naked, and short, averaging 76 millimeters (2.9 inches) (Kern 1991).
DISTRIBUTION: Dry, sandy habitats of the southeastern United States, from northern and central Florida northward across southern and central Alabama and Georgia (Pembleton and Williams 1978). Within Alabama, recorded historically from approximately 16 counties, all located within the upper and lower coastal plain east of Mobile Bay and the Tombigbee and Black Warrior River systems (B. Hart, pers.comm.). Over the past 30 to 40 years, however, apparently isolated, or remnant, populations in Bibb and Tuscaloosa Counties, have been extirpated. A recent study by researchers at Florida A&M University reported extant populations at less than 20 localities in 11 Alabama counties (Kovarik et al. 2000). The same authors reported that the species had been locally extirpated at approximately 17 other sites.
HABITAT: Well-drained, sandy habitats (i.e., sand hills, sand ridges, and upland or xeric hammocks) of the Atlantic and Gulf Coastal Plain characterized by such overstory dominants as longleaf pine, turkey oak, and live oak (Wilkins 1987).
LIFE HISTORY AND ECOLOGY: Breeds throughout the year with the peak of reproductive activity occurring January through August (Whitaker and Hamilton 1998); majority of births occur in March or July and August (Kern 1991). Litter size ranges from one to three, with reproductively active females producing one or two litters per year (Brown 1971 and Wing 1960). Newborns average around 50 millimeters (approximately two inches) in length, with an average weight of 5.8 grams (0.20 ounce) (Barrington 1942). Young usually weaned within one month of birth and reach sexual maturity in four to six months (Pembleton and Williams 1978). Well adapted for specialized existence; have muscular fore limbs, and enlarged front feet and claws, well adapted for burrowing through the sandy soils, and heavy, protruding incisors well suited for gnawing through roots, bulbs, tubers, and rhizomes that obstruct burrow construction, and also serve as principal food items (Whitaker and Hamilton 1998). As food items are encountered, they are transported in the external cheek pouches for storage in underground caches (Humphrey 1992; Wilkins 1987). Except during mating, solitary and extremely territorial. Burrows of females usually are localized while those of males generally are constructed in a straight line and often extend for 61 meters (200 feet), or more. For both sexes, burrows are constructed parallel to the surface, and are usually from 15 to 60 centimeters (six to 26 inches) below the surface (Kern 1991). Location of a burrow system usually is indicated by cone-shaped piles of loose sand pushed to the surface during burrow construction. Typically there are six to 12 of these piles, or mounds, associated with each burrow system. Mounds are connected to burrow system by diagonal tubes; however, the tubes themselves are plugged with sand so that no part of the burrow system is visible and open to the surface. This strategy is apparently intended to discourage predators. In Florida, this is especially the case for the principal predator, the Florida pine snake. Other predators elsewhere within the distribution of the pocket gopher include weasels and skunks (Kern 1991). On the rare occasions when pocket gophers emerge from their burrow systems they would be most susceptible to predation by owls, foxes, and coyotes. Approximately 80 species of insects, and other invertebrates, are known to utilize the burrow system, with at least 14 of these species known only from such habitats (Pembleton and Williams 1978).
BASIS FOR STATUS CLASSIFICATION: Because of low reproductive and dispersal rates, alteration and fragmentation of areas of suitable habitat, usually as a result of changing land use or intensified agricultural and silvicultural practices, have been the principal reason for the decline or elimination of populations throughout former distribution (B. Hart and R. H. Mount, pers. comm.). Another possible factor may be the reduced incidence of fire, which favors woody overstory vegetation that shades out the grasses, legumes, and other herbaceous species required as food (Kovarik 2001). Due to its demonstrated fondness for roots and tubers of certain agricultural crops (notably sweet potatoes, peanuts, sugarcane, alfalfa, and peas) and pasture and lawn grasses (particularly bahiagrass), the pocket gopher historically has been classified as an agricultural pest (Kern 1991). Consequently, agricultural extension services and various state and federal agencies have occasionally published fact sheets and instructional publications providing technical information and suggestions for controlling or eliminating them from gardens, crop fields, golf courses, and home or ornamental landscapes (Kern 1991). Although generally effective on a small scale, such control strategies have not played a major role in decline of this species.
Author: J. Ralph Jordan, Jr.