The breeding season begins in the spring, when males give short rasping calls to attract females. Males and females may fight each other, apparently as part of the courtship process. Eggs are laid mainly from mid May to mid June in an open, sunny place (4). Between one and 25 white, spherical eggs are laid in batches of five to six in holes dug into the ground, and the tiny hatchlings must dig their way to the surface when they emerge 100 days later (2). Sex is determined by temperature in turtles, so those eggs that are incubated at over 30 ºC will be females, and those below 30 ºC will be males (5). After emerging the hatchlings are protected by their parents in long, deep burrows (2), but may still be eaten by raccoons, skunks, armadillos, foxes and opossums (4). Sexual maturity is only reached at 16 – 21 years, and gopher tortoises may live for over 40 years (2). After sleeping at night in a burrow, the diurnal gopher tortoise will emerge to feed during the day (2). It is herbivorous, eating grasses and low herbs, as well as occasional fruits and berries (2). A natural fire regime is important in the gopher tortoise's habitat as rapidly moving wildfire will clear scrub, open the canopy, and encourage the growth of the vegetation eaten by the tortoises, who remain safe in their burrows during these fires (5). Each tortoise has a well defined home range which contains several burrows (4). Gopher tortoises are considered to be a 'keystone' species as their burrows, both active and abandoned, are used by over 100 other vertebrates and invertebrates, such as burrowing owls, raccoons and snakes (2) (4).

The gopher tortoise has a light to dark brown, elongate upper shell and dull yellow plastron. The skin is greyish brown and the head is large and blunt. The hind feet are small, stumpy and without webs (2). The front legs are shovel-like for burrowing in sand (4).

The gopher tortoise is found in the southeastern part of the United States. Its range includes southwestern South Carolina, south almost to the tip of the Florida peninsula; west through southern Georgia, Alabama, and Mississippi, to Louisiana and the edge of southeastern Texas and Arkansas

Biogeographic Regions: nearctic (Native )

endemic to a single nation

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Southeastern United States from southern South Carolina (Clark et al. 2001) through southern Georgia to southern Florida (excluding most of inland southern Florida), west through southern Alabama and southeastern Mississippi to eastern Louisiana (Diemer 1989). Occurs on islands off the Gulf coast of Florida as far south as Cape Sable (Logan 1981, Kushlan and Mazzotti 1984, Mushinsky and McCoy 1994). Most common in southern Georgia and northern and central Florida (Diemer 1989). At the northern end of the range in South Carolina, four disjunct populations remain in Jasper County and a few tortoises occur in southern Hampton County (Wright 1982); recently found in Aiken County (Clark et al. 2001). In Georgia, large populations occur in the western Fall Line Sand Hills and the central Tifton Uplands (Landers and Garner 1981); severely fragmented populations occur in the Coastal Plain. The largest remaining population in Mississippi is in Desoto National Forest (Lohoefener and Lohmeier 1984). A few populations remain at the western edge of the range in eastern Louisiana. For a detailed range map, see Iverson (1992).

Continent: North-America
Distribution: USA (along the Atlantic Coastal Plain in S South Carolina, Georgia, S Alabama, Florida, E Louisiana, Mississippi)  
Type locality: vicinity of Savannah, Georgia (restricted by K.P. SCHMIDT 1953)

Historic Range:
U.S.A. (AL, FL, GA, LA, MS, SC)

The distribution of gopher tortoise is generally correlated with the original range of longleaf pine forests according to U.S. Fish and Wildlife Service estimates (USFWS 1990). Along the Atlantic coast, G. polyphemus occurs from southern South Carolina, through Georgia and Florida. Beyond this area of the range, disjunct populations occur westward through southeastern Louisiana. The segment of the population that occurs westward from the Tombigbee and Mobile Rivers in Alabama is federally listed as threatened. Gopher tortoises are found in all counties in Florida and utilize many habitat types, from beach dunes to scrub and pine flatwoods. Though it is generally agreed that typical gopher tortoise habitats are sandy and well-drained, Breininger et al. (1991) observed that in Brevard County, Florida, gopher tortoises often inhabit poorly-drained scrub and slash pine areas. The Breininger et al. (1991) study reported higher overall tortoise densities in poorly-drained areas than in well-drained, sandy areas.

This species is found in the south-eastern part of the United States, from south-western South Carolina down to the Florida peninsula and west to Louisiana (2).

The upper shell is brown or tan, with growth rings evident on younger individuals, but these are worn away on adults. The under shell is unhinged, dull yellowish in color, with the soft parts being grayish brown. The upper shell can range in length from 107 mm to 240 mm. The feet of this tortoise are stumpy and without webs, and their heads are large and blunt. Compared to the other species in the genus Gopherus, the gopher tortoise's head is broad, hind feet small, and shell elongate.

Range length: 170 to 240 mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Average mass: 5500 g.

Average basal metabolic rate: 0.579 W.

Length: 28 cm

Body length averages 25 cm (10 inches); shell height ranges from 15 - 37 cm (6 - 15 inches); body mass averages 4 kg (9 pounds). G. polyphemus can be long-lived. Age estimates for tortoises in the wild ranges from 40 - 60 years; however, captive tortoises can live more than 100 years (Landers et al. 1980).

This is the only terrestrial tortoise east of the Mississippi River. The only other terrestrial turtle within the geographic range of the gopher tortoise is the eastern box turtle. Box turtles are smaller than gopher tortoises, have a high domed carapace, and a hinged plastron. Box turtles can close their shells completely so that neither the head nor any appendage is visible when retracted completely. Gopher tortoises cannot withdraw completely into their shells. A startled gopher tortoise will withdraw its limbs into the shell, but the limbs are visible when retracted.

Gopher tortoise differs from the desert, Texas, and bolson tortoises (none of which occur in the range of the gopher tortoise) in having relatively smaller hind feet. In the desert, Texas, and bolson tortoises, the distance from the base of the first claw to the base of the fourth claw on the forefoot is approximately equal to the same measurement on the hind foot; in the gopher tortoise, the measurement is smaller on the hind foot (Ernst and Barbour 1989).

The habitat of the gopher tortoise is in sandy ridge and sand dune areas where the water table never comes near the surface. The forests of longleaf pine, Pinus palustris, are also prime areas for gopher tortoise habitation.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: desert or dune ; savanna or grassland ; forest

Comments: Commonly occupies habitats with a well-drained sandy substrate, ample herbaceous vegetation for food, and sunlit areas for nesting (Hallinan 1923, Landers 1980, Landers et al. 1980, Diemer 1989). These habitat types include sandhill (pine-turkey oak), sand pine scrub, xeric hammock, pine flatwoods, dry prairie, coastal grasslands and dunes, and mixed hardwood-pine communities (Landers and Speake 1980, Auffenberg and Franz 1982, Kushlan and Mazzotti 1984, Diemer 1986, 1992a). Prefers open habitats that support a wide variety of herbaceous ground cover vegetation for forage; usually abandons densely canopied areas and frequently can be found in disturbed habitats such as roadsides, fence-rows, old fields, and the edges of overgrown (unburned) uplands (see Diemer 1989, Stewart et al. 1993, Breininger et al. 1994). Upland habitats with extensive canopies reduce the amount of direct sunlight on the ground which may hamper tortoises from reaching minimum thermal requirements for normal daily activities. Also, excessive shade decreases herbaceous vegetation essential for growth, development, and reproduction (Mushinsky and McCoy 1994).

Temporarily abandons marginal habitats during periods of drought; increasing habitat isolation eventually may result in marginal habitats being completely abandoned (Matthews and Moseley 1990). In Georgia, adults congregated on droughty sites in early spring, and many moved to more mesic soils for autumn-winter (McRae et al. 1981).

Densities of gopher tortoises are known to be relatively high in sandhill communities, however, high densities may not be indicative of a healthy population (Mushinsky and McCoy 1994). Mushinsky and McCoy (1994) reported that high densities of some tortoise populations may be the result of tortoises confined to a true or "habitat" island. Tortoises in this situation are unable to move freely to new locations as the quality of the habitat degenerates. More research is needed on the demography of tortoises in confined areas.

Gopher tortoises are highly fossorial and construct extensive burrow systems. They spend much of the time underground. See ecology section for further information on burrows.

Eggs are deposited in a typical flask-shaped nest cavity excavated by the hindlimbs of the female to a depth of about 10-15 cm. Nests may be located in any open sunny area near the burrow of the female, but most often, nests are placed in the spoil mound immediately outside the female's burrow (e.g., Hallinan 1923, Allen and Neil 1951, Arata 1958, Mount 1975, Landers et al. 1980, Butler and Hull 1996).

The gopher tortoise prefers dry landscapes such as sandy ridges and sand dunes, as well as the forests of longleaf pine (Pinus palustris) (2) (4).

Systems

• Terrestrial

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Individuals generally maintain a well-defined home (activity) range. A large one may encompass up to 6+ hectares over several years (Douglass 1990). Available information indicates that home range size generally is less than 5.3 hectares and averages less than 1.9 hectares, with the largest sizes in adult males and the smallest in juveniles (Auffenberg and Iverson 1979McRae et al. 1981b, Doonan 1986, Diemer 1992c, Wilson et al. 1994, Smith et al. 1997, Eubanks et al. 2003, Riedl 2006, Beauman 2008). Reported movements between and from burrows generally average less than 80 meters and often much less than that (mean of 20 meters or less) (McCrae et al. 1981b, Diemer 1992c, Wilson et al. 1994, Mushinsky et al. 2003). However, in southwestern Georgia, Beauman (2008) recorded multiple movements of around 200-400 meters between successive locations.

Movements of hatchlings tend to be limited but sometimes can be extensive. In east-central Florida, home range size (minimum convex polygon) of hatchlings averaged 1.95 hectares and two hatchlings had home ranges of 4.8 hectares (Pike 2006). Hatchlings moved farther from the nest over time; by the spring following hatching, hatchlings were an average of around 70-80 meters from the nest (Pike 2006). In Mississippi, 7 hatchlings surviving 41-736 days dispersed 17.5 to 458 m (mean about 130-160 m) from their nest (Epperson and Heise 2003). In northern Florida, mean home range of hatchlings during the active period was 363 sq m; mean annual range of nine individuals surviving a year was 2,032 sq m, and their mean total range after about two years was 2,554 +/- 1382 sq m (Butler et al. 1995).

Tortoises sometimes make long distance movements. Using radio-telemetry, Diemer (1992c) found that of her radio-tagged animals the longest movement made was 0.74 km by an emigrating subadult. Juveniles also may make long distance movements, usually following some type of disturbance to the resident burrow (Diemer 1992c, Wilson et al. 1994). Two adult males in Georgia dispersed 1.2 km and 1.5 km (straight-line distance to final known location) (Eubanks et al 2003). An adult female resided in two adjacent burrows for 11 months, then moved 2.1 km to a new location, where it resided for at least 9 months (Ashton, unpublished, in Mushinsky et al. 2006).

Size of home range has been shown to decrease with an increase in the amount of herbaceous ground cover (Auffenberg and Iverson 1979, Mushinsky and Gibson 1991). Management of habitat by controlled burning increases the amount of herbaceous ground cover, such that tortoises do not have to travel far from their burrows to find ample food. Thus, home ranges for this species may vary among populations depending on the quality of the habitat (Diemer 1992c, Mushinsky and McCoy 1994).

Overall, the gopher tortoise is an herbivore that enjoys low vegetation. The gopher tortoise spends most of its foraging time grazing in areas with a good supply of grasses and low herbs. Its food primarily consists of grasses and leaves with the occasional wild fruits and berries. In captivity gopher tortoises have been known to be fond of watermelon and cantaloupe rinds.

Comments: Gopher tortoises feed primarily on grasses and other herbaceous plants (Carr 1952, Garner and Landers 1981). Sometimes eats insects, carrion, and fruits.

Macdonald and Mushinsky (1988) identified 26 families of plants from 68 genera in scat analyses and foraging observations of gopher tortoises. The most common families of plants ingested were the Poaceae, Asteraceae, Fabaceae, Pinaceae and Fagaceae. The most common genus of plants ingested was Aristida (see also Wright 1982). Insects were found in 75% of scats and charcoal in 67% suggesting intentional ingestion of these items. Compared to adults, young tortoises tend to ingest fewer plants of the family Poaceae and plants with external defense mechanisms and more forbs such as legumes; they may negatively select Aristida even if it is abundant (Garner and Landers 1981, Macdonald and Mushinsky 1988, Mushinsky et al. 2003).

Macdonald and Mushinsky (1988) concluded that gopher tortoises tend to fall somewhere between a generalist and a specialist forager and prefer some plants over others with respect to their availability in the habitat. Rocks may be intentionally ingested as a source of minerals. During a study on the reproduction of adult female gopher tortoises in central Florida, radiography revealed that a large proportion of the females contained rocks in their digestive tracts (Mushinsky and Wilson, unpublished data). Digestive efficiencies of the gopher tortoise have been studied by Bjorndal (1987). Feeding occurs usually within 50 m of the burrow (Diemer 1992).

Gopher tortoises are primarily herbivorous, with the bulk of the diet consisting of low-growing herbs and grasses. Foods most common in the diet are grasses and legume fruits. They are also known to consume pine needles and seeds, oak mast, prickly pear cactus, asters, palm tree fruits, raspberries, black cherry, and gopher apples (Landers et al. 1980; Auffenberg and Franz 1982; Diemer 1986). Gopher tortoises have also been observed to eat mollusk shells and the bones of dead animals, possibly to supplement their diets with additional calcium.Competitors: Predators of gopher tortoises include various snakes, fire ants (Solenopsis saevissima), accipiter hawks, buteo hawks, raccoons, opossums, armadillos, skunks, dogs, foxes, feral cats and man all prey on gopher tortoises. Generally, eggs and hatchling tortoises are significantly more at risk for predation than older animals.Habitats: Gopher tortoises use a variety of habitats, including beach dunes, scrub, and pine flatwoods. In all habitat types, soils are generally dry, sandy and well-drained. While generally avoiding swampy areas, gopher tortoises in Brevard County, Florida have been observed to inhabit poorly-drained scrub and slash pine flatwoods (Breininger et al., 1991). In this county, higher densities of gopher tortoises were found in poorly-drained sites than in well-drained sites.Individuals occupy distinct home ranges, with male home ranges typically being larger than those of females. In east-central Florida, home ranges of male tortoises averaged 1.9 ha (4.7 ac), while those of females averaged only 0.65 ha (1.6 ac). A tortoise excavates several burrows for its use within the home range. Burrows typically are dug at a 30? angle from the surface. In Florida studies, male tortoises dug between 8 - 35 burrows. Females tended not to use as many burrows as males, averaging between 3 - 17 burrows (Breininger et al., 1988).Tortoise densities tend to be higher in fire-adapted communities (Auffenberg and Franz 1982; Diemer 1986). In the absence of fire, canopy trees grow large and shade out the herbaceous vegetation that gopher tortoises rely on as their primary food source.

Gopherus polyphemus is considered a keystone species in that more than 80 different species live in their burrows, or are dependent on their burrows for protection. Some of these species, such as the gopher frog (Rana areolata), the pine snake (Pituophis melanoleucus) the indigo snake (Dymarchon corais), the scrub jay (Aphelocoma coerulescens) and in inland prairies, the burrowing owl (Athene cunicularia floridana) are rare (Burke and Cox 1988; Spillers and Speake 1988; Stout et al. 1988;Witz et al. 1991).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Several hundred EOs of varying quality in Florida and southern Georgia; nearly extirpated in South Carolina and Louisiana; relatively rare in Mississippi and Alabama.

10,000 to >1,000,000 individuals

Comments: Large numbers still exist, but see GTREND.

The gopher tortoise is listed in Florida as a Species of Special Concern (SSC). Auffenberg and Franz (1982) have estimated that historical population densities of this species had been reduced 70% by the year 2000, and could be extirpated from all but protected land areas by 2025. Merritt Island Wildlife Refuge at Kennedy Space Center (KSC) in Florida is the largest protected area of gopher tortoise habitat along the Atlantic coast. Overall tortoise density at KSC is estimated at approximately 18,000 animals, with tortoise density highest in areas where herbaceous cover dominates. Tortoise density decreases in areas where cover of shrubs, oak trees and pines dominates (Breininger et al. 1988, 1991, 1994).Locomotion: Gopher tortoises walk and burrow.

BURROWING AND BURROW ECOLOGY: Gopher tortoises excavate deep burrows that provide shelter from climatic extremes and refuge from predation. Adult burrows average approximately 4.5 m in length and about 2 m deep (Diemer 1989; see Guyer and Hermann 1997 for information on burrow size and longevity at sites in Georgia and Alabama). Burrows have been found to be significantly shorter in clayey soils than sandy soils which may be a result of respiratory limitations (Ultsch and Anderson 1986); oxygen decrements and carbon dioxide increments were greatest in clayey soils and were positively correlated with burrow length. The high humidity associated with the burrow may offer the tortoise protection from desiccation (Auffenberg and Weaver 1969, Means 1982). At the mouth of each burrow is a mound of subsoil excavated by the burrow resident. Kaczor and Hartnett (1990) found that these soil mounds undergo microsuccession and contribute toward increased plant species diversity in the surrounding habitat.

In northern Florida, Diemer (1992c) found that, on average, adult male tortoises use 5.5 burrows and adult female tortoises use 2.7 burrows per activity season (April-December). In Georgia, tortoises were reported to use 7 and 4 burrows for males and females, respectively (McRae et al. 1981b). Average number of burrows used annually by juvenile tortoises was 1.1 by 0-1- year-olds, 2.2 by 2-year-olds, and 1.7 by 4-5-year-olds in a southern Georgia population (McRae et al. 1981b) and 4.4 by 1-4-year-olds in a central Florida population (Wilson et al. 1994). At the Kennedy Space Center in Florida, Smith et al. (1997) documented the use of individual burrows by several tortoises at different times and occupation of individual burrows by two tortoises at the same time. Suggested reasons for differences in burrow use between populations include differences in ground cover, soil composition, temperature extremes at different latitudes, and number of disturbances to burrows.

Although juvenile tortoises use several burrows they spend most of their time in a primary burrow. Annual use of the primary burrow for juvenile tortoises in a central Florida population was 75% of the use of all burrows (Wilson et al. 1994). The data for estimated use of the primary burrow for adult gopher tortoises are not available. Hatchlings dig burrows (Epperson and Heise 2003) and, in their first year, use multiple burrows (Butler et al. 1995). Several studies have noted that gopher tortoises sometimes use shallow depressions, possibly as resting sites when traveling far from their burrows (Fucigna and Nickerson 1989, Godley 1989, Stout et al. 1989, Diemer 1992c), and windrows, possibly for protection from cattle and machinery (Diemer 1992c). On pine plantations in Alabama, most burrows of juveniles were associated with stumps, fallen logs or tree limbs, or shrub stems, which could interfere with excavation attempts by predators (Aresco 1999). Ashton and Ashton (2001) documented the use of apparently abandoned burrows by juveniles in Citrus County, Florida.

In Northern Florida, Diemer (1992b) studied tortoise populations for several years. She found that the number of burrows showing signs of recent activity increased in April, peaked in July, and remained high through October. The burrow surveys showed a continuous cycle of burrow creation and abandonment. The ratio of captured tortoises to burrows (active and inactive) varied among sites and years; the ratio of burrows to tortoises ranged from 0.45-0.69. Percentages of adult individuals in the three populations studied ranged from 40-62%.

Gopher tortoises desiccate more rapidly when deprived of a burrow than any other member of the genus Gopherus (Auffenberg and Weaver 1969). They may withstand relatively high body temperatures (Bogert and Cowles 1947) but froth at the mouth and breathe rapidly when heat stressed. Critical thermal maximum is reported as 43.9 C (Hutchinson et al. 1966).

Many vertebrate and invertebrate species have been recorded from gopher tortoise burrows (Young and Goff 1939, Brode 1959, Hansen 1963, Franz 1986, Jackson and Milstrey 1989, Lips 1991, Witz et al. 1991), including protected species such as the eastern indigo snake (Drymarchon corais COUPERI) and the gopher frog (Rana capito) (Auffenberg 1969, 1978; Diemer 1986). Some burrow associates prefer active burrows over inactive or abandoned ones (Lips 1991); these can be distinguished by characteristics of the burrow entrance (Auffenberg and Franz 1982, Cox et al. 1987). Eisenberg (1983) found that 73.7% of gopher frogs censused were found in active tortoise burrows. Witz and coworkers (1991) excavated 1019 burrows and found that of the vertebrate symbionts captured only lizards were found significantly more often in active burrows than in either inactive or abandoned burrows. Fecal material and other organic debris in the enlarged area at the bottom of the burrow serves as an important food source for some burrow associates (Milstrey 1986).

POPULATION ECOLOGY:

Often occurs in more or less isolated colonies of up to about 57 individuals; population density within a colony was estimated at 3-27/ha in Florida (Auffenberg and Franz 1982). Folk (1993) estimated density at about 1-2/ha, 3-5/ha, and 16-25/ha on 3 TNC preserves in Florida. At the Kennedy Space Center, Florida, fall densities ranged from a mean of 2.7/ha in disturbed habitat to 0.0/ha in saw palmetto habitat; spring densities ranged from a mean of 2.5/ha in saw palmetto habitat to 0.7/ha in oak-palmetto habitat (Breininger et al. 1994).

A comprehensive study of about 50 populations of gopher tortoises in Florida (McCoy and Mushinsky 1988) found several trends. Gopher tortoise populations residing on sites that had experienced severe area reduction (greater than 25% reduction over the past 20 years), or occurred on sites with greater than 50% tree canopy, or occurred on sites of small size (< 2 ha), tended to have truncated demographic profiles. A truncated profile suggests little recruitment of individuals into the population and abandonment of the site by larger, mature individuals. In contrast, tortoise populations on sites with no or limited area reduction, or sites with less than 50% tree canopy, or relatively large sites (> 2 ha) tended to have a high proportion of large, mature individuals and evidence of recruitment of young into the population (McCoy and Mushinsky 1988).

Comparisons of tortoise populations on true islands with populations on the mainland suggested that tortoises do respond to relatively small, isolated habitats (Mushinsky and McCoy 1994). Both island and mainland tortoise populations show a positive relationship between the number of active and inactive burrows and the area of habitat. Density of burrows, however, decreased as area increased on the mainland, but density of burrows was not related to area on the islands. Also, on the mainland, the ratio of inactive to active burrows (a measure of the tendency of individuals to construct new burrows) increased with area of habitat, and burrow density increased with increasing herbaceous vegetation, but neither of these relations could be demonstrated on islands. Collectively, these findings suggest that tortoises have a greater selection of habitats on the mainland than on islands. Tortoises on islands are confined and may be forced to live in less than ideal conditions. The implications of these findings are profound for tortoises living in small, fragmented "habitat islands" on the mainland. In time, perhaps a few decades, as the quality of their habitat island is degraded, mature adults may be forced to abandon a site in search of better habitat quality. Such individuals, which may be forced to abandon isolated patches of habitat in areas surrounded by human dwellings seem doomed to perish. From a practical perspective, prior to this study (Mushinsky and McCoy 1994), observation of large numbers of active and inactive gopher tortoise burrows in a confined area likely would have been viewed as indicators of a "healthy" population; however, these findings suggest just the opposite. Rather than a signal of a healthy population, large numbers of active and inactive gopher tortoise burrows, relative to the actual number of tortoises, may signal a stressed population (see also Stewart et al. 1993).

Comments: Spends a limited amount of time above ground outside of the burrow. With a device that automatically recorded activity, Auffenberg and Iverson (1979) calculated that an adult tortoise was active 9.2% of its time. Juveniles have been reported to spend 90% of their time underground inside their burrows (Wilson et al. 1994).

Active all year except during cold spells (Ernst and Barbour 1972). Activity away from the burrow tends to peak in the late spring and summer. In northern Florida, the number of burrows showing active sign increased in April, peaked in July, and remained high through October (Diemer 1992). In southern Florida, activity peaked May-August (Douglass and Layne 1978). In southwestern Georgia, activity was severely restricted in winter (McRae et al. 1981). For juveniles, Wilson and coworkers (1994) found that 80% of observed activity in fall, winter and spring consisted of basking on the burrow mound; juveniles moved away from their burrows significantly more during the summer months. During the winter months, tortoises have been observed basking at the mouths of their burrows on warm days throughout their range (Douglas and Layne 1978, McRae et al. 1981b, Wilson et al. 1994). Thus, the activities of gopher tortoises away from their burrows are limited in the winter months and increase as seasonal temperatures increase.

Daily activity has been reported as unimodal in the spring and bimodal in the summer in a Georgia population (McRae et al. 1981b). These investigators suggested that adult tortoises may be active in the late morning and late afternoon in summer to avoid the hottest part of the day. In contrast, Douglass and Layne (1978) and Wilson et al. (1994) found that juvenile tortoises were more active in mid-afternoon and did not display a bimodal activity pattern in the summer. Activity patterns of juvenile tortoises may be influenced by the risk of predation and thermoregulatory behavior (see Wilson et al. 1994 and Wilson 1991). No evidence of nocturnal activity has been reported for the gopher tortoise.

Adult gopher tortoises require 16-21 years to mature, and can live 40 years or longer.

Average lifespan

Status: captivity: 8.5 years.

Observations: Their longevity in the wild likely exceeds 25 years (http://www.fs.fed.us/database/feis/). Anecdotal evidence suggests these animals may live over 100 years.

The mating behavior of the gopher tortoise is not well documented because of its secretive nature. Male gopher tortoises have been known to utter short rasping calls, to attract females. Fights between male and female gopher tortoises are also sometime seen, which could be related to courtship and mating. Males have a pair of glands under their chin that may function to attract females. The eggs of the gopher tortoise are laid in late April to July. They are deposited, five or six eggs at a time, in holes dug in the ground so that they are protected from the blazing sun. Once in the nest cavity the eggs incubate for approximately 100 days.

Breeding interval: Gopher tortoises breed once per year.

Breeding season: April through July

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous

Average gestation period: 90 days.

Average number of offspring: 8.

Average age at sexual or reproductive maturity (male)

Sex: male: 3650 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 3650 days.

Male tortoises seek females for mating from May to July. There is some evidence that dominant males breed with several females (Douglass 1990). When seeking a female, a male moves to the mouth of a burrow occupied by a female and displays a head bobbing behavior (Auffenberg 1966, Wright 1982). If the female exits her burrow the courting male walks in a circle around the female, periodically stopping and performing the head bobbing behavior. When the female approaches the courting male, he bobs his head violently, and bites her on the forelegs, head, anterior edge of the carapace, and gular projection. The female then backs in a semicircle, stops, and extends her hindlimbs. Thereafter, she rotates her body about 180 degrees, so that her posterior end is near the male's head. The courting male then attempts to mount the female; if unsuccessful, he repeats the courting behavior (Auffenberg 1966, Ernst and Barbour 1972).

Nesting occurs from late April to mid-July (mainly mid-May to mid-June) (Iverson 1980, Landers et al. 1980, Wright 1982, Epperson and Heise 2003)). Clutch size usually is 5-9, averages 3.8 in South Carolina, 5-6 in Florida (e.g., Butler and Hull 1996), 7 in Georgia (see Diemer and Moore 1994), 4.8 in Mississippi (Epperson and Heise 2003). A large female from central Florida produced an unusually large clutch of 25 eggs (Godley 1989). Clutch size increases with increasing female size (Landers et al. 1980, Diemer and Moore 1994). Adult females produce one clutch/year (but some adults do not nest every year). The ovarian cycle was described by Iverson (1980) and Palmer and Guillette (1988). Incubation lasts about 110 days in South Carolina, 80-90 days in northern Florida (Iverson 1980, Landers et al. 1980), mean of 105 days in northeastern Florida (Butler and Hull 1996), mean of 88 dyas in Mississippi (Epperson and Heise 2003). Hatching occurs from August through September. In northeastern Florida, hatchlings emerged from the nest from late August through early October (Butler and Hull 1996). At hatching, and about 24-48 hours prior to emergence, hatchlings exhibit a large external yolk sac (Linley and Mushinsky 1994). The external yolk sac is absorbed as the hatchlings remain in the nest cavity prior to emergence. Just after emergence a deep transverse groove across the plastron is visible; it disappears two to three days after emergence as the anterior- posterior axis of the body becomes straight and the plastron flattens (Ernst and Barbour 1972). This species exhibits temperature-dependent sex determination (Burke et al. 1996, Chelonian Conservation and Biology 2:86-88).

In Georgia, Landers and coworkers (1982) found that pronounced growth occurred through the age of 11 years, after which growth rate gradually decreased. In central Florida, Mushinsky and coworkers (1994) reported an average increase of 18.9 mm/year for ages 1-11, after which time growth slowed to approximately 3%/year until age 20.

Females become sexually mature at a carapace length of 23-24 cm. Body size, rather than age, seems to determine sexual maturity in gopher tortoises. In southern Georgia, it may take from 19-21 years for females to become sexually mature (Landers et al. 1982), while in central Florida females may mature in 9-11 years (Mushinsky et al. 1994). In part, this variation reflects the long activity season available to tortoises in central Florida. In addition to geographic location, however, local conditions also influence the number of years required to achieve sexual maturity. For example, one study of gopher tortoises in central Florida (Godley 1989) found that females attain sexual maturity in 14-16 years, while another study in the same county found that females attain sexual maturity in 9-11 years (Mushinsky et al. 1994). The study area occupied by the faster maturing females was a frequently burned sandhill habitat, whereas the other study area was a mosaic of habitats including pine flatwoods and mixed mesic forests. Males likely mature at a smaller size than females. In north Florida, Diemer and Moore (1994) reported males that were apparently mature at a carapace length of about 18 cm. Potential longevity is several decades.

The level of predation on eggs and young is high. For example, over a two- year period in South Carolina, 17 of 24 (74%) nests were destroyed (Wright 1982). In Georgia, an average female is estimated to produce a successful clutch of eggs (eggs are not destroyed prior to hatching) once a decade (Landers et al. 1980), because about 90% of their nests are destroyed annually. Common predators of eggs are armadillos (Dasypus novemcinctus), raccoons (Procyon lotor), grey foxes (Urocyon cinereoargenteus), striped skunks (Mephitis mephitis), and opossums (DIDELPHIS VIRGINIANUS) (Hallinan 1923, Ernst and Barbour 1972, Douglass and Winegarner 1977, Landers et al. 1980). Hatchling gopher tortoises (individuals in their first year of life) also are subjected to high levels of predation. From egg laying to one year of age, gopher tortoises in northern Florida were estimated to have a mortality rate of 94.2% (Alford 1980). Results from another study in central Florida, which also combined mortality of eggs and hatchlings, suggested an annual mortality rate of 92.3% (Witz et al. 1992). Estimated rates of survivorship of juvenile gopher tortoises (age 1 to 4 years) have been reported from one location in central Florida (Wilson 1991). Wilson (1991) found that predation of juvenile tortoises was higher in October-November and April-May than any other two month interval of the year. Juvenile tortoises are known to bask at the mouths of their burrows more often in the spring and fall of the year than during the summer or winter months (Wilson et al. 1994). It appears that a juvenile tortoise, when positioned at the mouth of the burrow to thermoregulate during the cool months of the year may be quite vulnerable to predation by avian and mammalian predators (Wilson 1991, see also Fitzpatrick and Woolfenden 1978).

Maturity is reached at 19 - 21 years of age in Georgia, 10 - 15 years in Florida. The reproductive season extends from February through September, with a peak throughout May and June (Diemer 1986). Females excavate nests in open, sandy areas. One clutch of eggs is laid per year, with an average of 6 eggs laid each season. However, clutch size varies depending on body size, and ranges anywhere between 3 - 14 eggs. Females may have only one successful brood every ten years, as most eggs do not survive to hatching. Mammalian predators such as foxes, raccoons, feral cats, and armadillos prey upon eggs. Landers et al. (1980) estimated that only 1 - 3 eggs of every 100 eggs survives to maturity.

Incubation time is approximately 100 days in Georgia, and 80 - 90 days in Florida. Sex of hatchlings is dependent on the temperature of the sand where the nest is sited. In gopher tortoises, average sand temperatures above 30? C (approximately 85? F) produce females, while those below 30? C produce males.Hatchlings measure approximately 3 - 5 cm (1.5 - 2 in.) long and are vulnerable to predation due to their soft shells. Growth rates in gopher tortoises are extremely slow, estimated to be less than 2.5 cm (1 in.) per year.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 1
Species With Barcodes: 1

Year Assessed

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The gopher tortoise has a vital community role and is known as a keystone species because of the wide use of their burrows by other animals (such as burrowing owls, raccoons, opossums, gopher frogs, snakes, etc.). Because they are a keystone species, the protection of the gopher tortoise is crucial for the whole ecosystem in which it lives. In some states the gopher tortoise is being protected by state agencies that are enforcing conservation laws and controlling illegal harvest. Besides protecting the tortoise against poaching other methods of conservation are being used. Relocation of gopher tortoises has been used, with success, to protect tortoises on land that is being developed. Reintroduction into areas from which the tortoises were driven has also been used. Protection of gopher tortoise habitat, such as sand dunes and longleaf pine forests, is also an alternative that can help keep populations high.

IUCN Red List of Threatened Species: vulnerable

Rounded Global Status Rank: G3 - Vulnerable

Reasons: Occurs in the southeastern U.S. from South Carolina to Louisiana; still common in some parts of range though rare in others; population has undergone 80% decline in last 100 years; decline is expected to continue with ongoing habitat loss; multiple threats to habitat plus direct human exploitation.

Other Considerations: Federally and/or state-listed throughout range; burrows are used by hundreds of other vertebrates and invertebrates, including many rare to threatened species such as the indigo snake, Florida mouse, and Florida gopher frog.

United States

Rounded National Status Rank: N3 - Vulnerable

Current Listing Status Summary

Status: Threatened
Date Listed: 07/07/1987
Lead Region:   Southeast Region (Region 4)   
Where Listed: W of of Mobile/Tombigbee Rs.

Status: Candidate
Date Listed:
Lead Region:   Southeast Region (Region 4)   
Where Listed: eastern


Population detail:

Population location: Wherever found west of Mobile and Tombigbee Rivers in AL, MS, and LA
Listing status: T

For most current information and documents related to the conservation status and management of Gopherus polyphemus , see its USFWS Species Profile

The gopher tortoise is classified as Vulnerable (VU) on the IUCN Red List (1), and is listed on Appendix II of CITES (3).

Global Short Term Trend: Decline of 10-30%

Comments: Formerly common in upland ecosystems throughout the southeastern United States; now threatened with extirpation in many areas and in serious decline in others. There has been an approximately 80% decline in the number of gopher tortoises in the last 100 years (Auffenberg and Franz 1982). Decline is predicted to continue to at least the year 2000.

Comments: Urban development and agricultural conversion (including commercial forestry) are the primary threats; also mining in some areas. Though illegal, hunting for human consumption still exists. Road kills are a minor problem.

Area reduction (habitat loss and fragmentation) and habitat degradation are two of the greatest threats. As either increases, the probability of local extirpation also increases. In combination, the effects of area reduction and habitat degradation likely increase the probability of extirpation in a synergistic fashion. Any development that fragments a population and/or creates a barrier to the natural movement of gopher tortoises likely will negatively impact that population.

Negative impacts also include predation on eggs and young by raccoons (e.g., Butler and Sowell 1996) and other predators and predation by humans. Intensive and/or sustained harvest by humans has seriously impacted some local populations (Diemer 1989). Fortunately, because of prohibition or regulation of harvest throughout most of the range, collecting for food has declined.

Exposure to and/or active signs of Upper Respiratory Tract Disease (URTD) have been recorded in Florida and Mississippi; the significance of this is not yet known, but the situation warrants monitoring (Smith et al. 1998). Diemer Berish et al. (2000) documented the presence of URTD in several locations in Florida. Seigel et al. (2003) reviewed available data on the disease and recent tortoise mortality and concluded that URTD may have a substantial negative impact on tortoise populations. Thomas and Blankenship (2002) sampled a Mississippi population and found no evidence of URTD.

In Florida, major causes of the decline include increased urbanization, incompatible silvicultural practices (chiefly conversion to densely planted sand pine or slash pine; the dense canopy of closely packed pine trees shades the understory, preventing the growth of grasses and herbaceous plants that provide food for gopher tortoises; Landers and Buckner 1981), phosphate mining, unmanaged habitats, and citrus production. Widespread development and destruction of upland habitats have fragmented large tortoise populations and pushed individuals into unsuitable habitats and onto highways (Diemer 1989). In the Florida panhandle, human predation on tortoises has drastically reduced populations (Auffenberg and Franz 1982, Taylor 1982, Diemer 1986); this was most severe during the Depression (Hutt 1967). Poor habitat management also is a serious threat. As the habitat becomes increasingly overgrown, large sexually mature adults leave the population in search of better forage with the result of a decrease in the recruitment of young into the population.

In Georgia, large populations of tortoises have been fragmented by extensive agricultural and urban development, the construction of dams (inundating upland habitat), and sand extraction (Landers and Garner 1981, Diemer 1989). Many populations in Georgia have been depleted because of overharvesting (Landers and Garner 1981, Auffenberg and Franz 1982). Large-scale rattlesnake roundups are a threat to many tortoise populations throughout the Georgia Coastal Plain.

In Mississippi, habitat loss to crops and pasturage is the primary reason for the decline; most remaining populations are on protected lands (Lohoefener and Lohmeier 1984). Alabama populations are reported to be recovering from past exploitation, but these populations are threatened by habitat degradation as a result of fire exclusion (Lohoefener and Lohmeier 1984). The few tortoise populations in South Carolina are threatened by human predation and slash pine monocultures (Auffenberg and Franz 1982). In Louisiana, most of the tortoise habitat has been converted into pine plantations (Lohoefener and Lohmeier 1984, Auffenberg and Franz 1982).

The gopher tortoise's habitat is created by a fine balance of natural processes such as wildfire, which due to habitat loss and fragmentation can no longer occur. Controlled burning is practised, but this is less effective than wildfire (5). Gopher tortoises have suffered from poaching for meat in the past, but now more commonly for pets. Whilst not harmed, pet gopher tortoises are not able to reproduce and this can therefore lead to serious population declines (5). At the current time, mortality on roads is thought to be the most common cause of human-induced death in gopher tortoises (5).

Conservation Actions

Restoration Potential: At Camp Shelby in Mississippi, low hatching success and high hatchling mortality may limit recruitment and inhibit recovery of the population from previous declines (Epperson and Heise 2003).

Preserve Selection and Design Considerations: Landers and Speake (1980) recognized that gopher tortoises can be maintained on small management units, but they proposed that larger units (up to several hundred hectares) would lessen the impact of emigration and mortality. Similarly, Cox et al. (1987) suggested that areas of 10-25 ha (25- 70 acres) of favorable, managed habitat should be set aside for populations occupying lands slated for development. Perhaps the most extensive study of gopher tortoise populations was that conducted by McCoy and Mushinsky (1988). They surveyed a wide variety of sites for tortoises, including some of the largest federal lands in Florida as well as numerous, relatively-small, largely unprotected populations of tortoises. They recognized the importance of protecting, if possible, large areas (tens to hundreds of hectares) of gopher tortoise habitat, but emphasized the value of the numerous small isolated populations that exist throughout the range of the tortoise. McCoy and Mushinsky (1988) pointed out that gopher tortoises function as "keystone species" (Campbell and Christman 1982, Jackson and Milstrey 1989), and therefore merit special consideration in ranking conservation priorities.

Conservation of large areas of land has the potential side-effect of creating false security about the future of resident tortoises. Continuous management is critical to these populations; but tortoises occupying extant large conservation areas typically have not been so managed (McCoy and Mushinsky 1992b). Development patterns throughout peninsular Florida are such that it is not practical to set aside even 10 ha of land in many places. McCoy and Mushinsky (1988) believed it unwise to place full emphasis upon the single large area notion of conservation. Rather they proposed that greater emphasis be placed upon alternate conservation strategies for the gopher tortoise in Florida. They proposed a two-pronged approach. Whenever feasible, large areas of land should be secured, with the stipulation that rigorous management practices are to be employed to monitor continuously the demographic health of the resident population. In parallel with the securing of large areas, they recognized a need to secure large numbers of small areas. Such small areas allow "banking" of genetic diversity, as well as of individuals, for decades or perhaps longer. Management practices tailored to these small areas might even be able to perpetuate a metapopulation for tens of decades or longer.

Dichotomies created between apparently suitable and less-than-suitable gopher tortoise habitats may be misleading, and cause some small sites to be dismissed too quickly as unworthy of conservation effort. It seems imperative to view tortoise habitat quality as a dynamic gradient. Area reduction and habitat degradation are two of the greatest threats to the future of tortoise populations: as either increases, the probability of extinction also increases. In combination, the effects of area reduction and habitat degradation likely increase the probability in a synergistic fashion. Hence, while tortoises on large areas of land are in need of continuous monitoring, tortoises on small areas are likely in need of continuous management as well. Each state in which the gopher tortoise resides should serve as steward over these small areas of land, to coordinate research efforts designed to address critical questions regarding tortoise management on them, and to serve as a clearing house for all translocations of individuals among them. Research priorities concerning management of small areas should include delineation of the potential consequences of tortoise translocation and derivation of methods of increasing site tenacity.

Management Requirements: Recommendations for specific management procedures for gopher tortoises have been made by Landers and Speak (1980) for Georgia, Wright (1982) for South Carolina, Lohoefener and Lohmeier (1984) for Louisiana, Mississippi, and Alabama, and Auffenberg and Franz (1982) and Diemer (1986, 1994) for Florida. Conservation measures include habitat management, establishment of preserves, protection from overharvest, and public education (Landers 1980, Diemer 1986, Diemer-Berish 1994).

Maintenance of gopher tortoises populations generally requires active habitat management, even on seemingly "protected" lands owned by states or the federal government (McCoy and Mushinsky 1992b). Active management of upland habitats increases food abundance and nest site availability for gopher tortoises (Landers and Speak 1980). Gopher tortoises prefer, and attain their highest densities, in grassy, open-canopied sites (Auffenberg and Franz 1982, Mushinsky and McCoy 1994). Prescribed burning is the preferred method for managing gopher tortoise habitats (Landers 1980, Mushinsky and Gibson 1991).

The details of any habitat management program aimed at maintaining or increasing the number of gopher tortoises present in an area must be site specific. However, the goal should be to produce a mosaic of vegetation density by altering the frequency and timing of controlled burns (Diemer-Berish 1994). Habitat management that reduces excessive canopy cover and promotes a lush herbaceous ground cover (burning or stand thinning) is desirable. Optimal conditions include multi-aged forest, ranging from treeless areas with high diversities and abundances of grasses and herbaceous plants to areas with tree canopies that cover about 30-50% of the area. Summer burning mimics the natural fire cycle, promotes flowering of annual herbaceous plants, and facilitates the production of seeds by many of the grasses. Sandhill habitat responds well to summer burns on a 2-7 year periodicity. Pine flatwoods also should be subjected to summer burns on a 2-5 year cycle to encourage the production of the plants used as forage by gopher tortoises. Sand pine scrub habitat should be burned less frequently, perhaps every 15-30 years. A highly overgrown site may be first burned during the winter months to reduce the risk of a very hot fire and to thin the canopy prior to implementing a cycle of summer burns which promote vegetative regrowth. Activities that involve root-raking and windrowing should be avoided.

Because predation on tortoise eggs and hatchlings is great, protection of these stages of their life history has been recommended (Wright 1982). Nests can be protected by predator-proof enclosures, and predators can be removed by hunting or trapping (Landers 1980).

Restocking of all ages of tortoises to sites they formerly occupied has been attempted. Over the years, these relocations have involved thousands of individuals, particularly in Florida. However, the fate of most relocated tortoises is unknown (Diemer 1986). In south Georgia, about 40% of the tortoises introduced into an area remained in that area three years after their introduction (Landers 1981). In north Florida, Diemer (1987b) recaptured about 30% of relocated tortoises five years after their release. These studies suggest that most tortoises quickly abandon sites to which they have been relocated (or that mortality rate is high).

See Burke (1989) and Dodd and Seigel (1991) for a discussion of, and references pertaining to, tortoise relocations.

See Kpoeny (1991) for information on Florida's proposed incidental take rule.

Management Research Needs: Three recent reports summarize topics in need of further study for North American tortoises (Burke and Cox 1988, Germano and Bury 1994, McCoy 1994). Below is a selected summary of those recommendations that are particularly pertinent to management needs.

1. Quantification of habitat use.

2. Definition of habitat requirements.

3. Determination of what constitutes "quality" habitat.

4. Improving methods to determine tortoise density.

5. Long-term studies to determine temporal variability.

6. Studies on egg and hatchling survivorship.

7. Behavioral studies to determine social interactions and hierarchies.

8. Genetic studies of parentage and selective mate assortment.

9. Genetic studies to determine gene exchange among neighboring populations.

10. Studies on homing and orientation.

11. Studies of the long-term success of relocated tortoises.

12. Studies of diseases and disease transmission among populations.

13. Studies of nutritional requirements and foraging preferences of free ranging tortoises.

14. Long-term studies designed to understand natural population trends.

15. Identification of factors that contribute to local extinctions of small populations.

16. Estimates of minimum viable population size.

17. Genetic studies to determine variation and heterozygosity of populations of tortoises throughout their range.

18. More studies concerning alternate habitat management techniques in areas where burning is not feasible.

Global Protection: Many to very many (13 to >40) occurrences appropriately protected and managed

Comments: Occurs in many state and national parks and forests, as well as on a number of TNC and university preserves (see ESRs). However, compatibility of habitat management with gopher tortoises varies greatly.

Needs: Protect occurrences, enforce bans on hunting and collecting.

Protection by the US Fish and Wildlife Service and the Florida Fish and Wildlife Conservation Commission has made it illegal to keep gopher tortoises as pets, race them, or remove them from their natural range (5). Conservation of their natural habitat is of the highest priority, and relocation has been used to protect individuals during development of land (2). However, further habitat destruction and fragmentation will not only harm the gopher tortoise, but also the many species that depend on its burrowing habits.

There are few negative aspects of the gopher tortoise. The occasional damage of crops by hungry tortoises and the relocation costs of developers needing to relocate tortoises from areas being built are the only negative aspects.

Ancient Indians had a monetary system that used gopher tortoises in the place of money. Shells of the tortoises have served as baskets, pots and even sun helmets. Even today, they are a source of food for poorer rural people of Florida and south Georgia.

Gopher tortoises play an important role in structuring the habitats within ecosystems. They are Federally listed as threatened in Louisiana, Mississippi, and Alabama. In Florida, they are listed as a Species of Special Concern (SSC).Benefit in IRL: Gopher tortoises play an important role in ecosystem ecology for two reasons. First, by consuming grasses, herbs, and the fruits of trees, the gopher tortoise aids in seed dispersal. Second, its burrows provide important habitat for more than 80 different species of invertebrates and vertebrates, some of which are rare.

Stewardship Overview: The gopher tortoise, Gopherus polyphemus, is a large, herbivorous terrestrial turtle that is found in six states in the southeastern United States. Gopher tortoises most commonly are found in upland areas that are characterized by a deep, well-drained, sandy substrate suitable for construction of their extensive burrows. The gopher tortoise prefers relatively open-canopied habitats that provide sunlit areas for nesting and thermoregulation, and ample herbaceous ground vegetation for forage. Because the gopher tortoise is seldom found above ground outside of its burrow, it is often necessary to use tortoise burrows as a means of assessing populations. Burrows within a defined area are designated a status or condition based on time since occupancy. The width of a burrow can be measured to estimate the size of the current resident tortoise. With these survey data, population counts and size class distributions can be determined for populations under study.

Historically, gopher tortoises were considered common in upland habitats throughout their range, however, this species now faces numerous threats to its continued survival in many areas. Overharvesting by humans, as well as habitat destruction, degradation, and fragmentation have contributed to the decline of this species. Because the gopher tortoise is long-lived with delayed sexual maturity and a low reproductive potential, it is essential to develop management schemes that offer the tortoise adequate protection. Management schemes must be formulated to address the needs of the specific population under consideration. Along with current conservation measures of habitat protection and restrictions on harvesting by humans, public awareness through comprehensive public education is imperative for the continued persistence of this species.

Species Impact: Gopher tortoises compact soil and alter vegetation composition near their burrows (Boglioli et al. 2000).

Comments: Auffenberg (1976), Bramble (1982), Crumly (1987, 1994), and Lamb and Lydeard (1994) provided information on phylogenetic relationships among tortoises of the genus Gopherus, which comprises four living species and nine fossil taxa. A recent study of phylogeny based on mtDNA variation identified the four living North American tortoises as a monophyletic group consisting of two well-defined clades, the agassizii clade and the polyphemus clade (Lamb and Lydeard 1994). MtDNA and osteological data indicate that G. polyphemus is more closely related to G. flavomarginatus of Mexico than it is to the other two species of Gopherus. Gopherus polyphemus is only slightly distinct from G. flavomarginatus based on allozymes (Morafka et al. 1994).

Using mtDNA, Osentoski (1993) assessed rangewide genetic variation and found three major assemblages: (1) a western assemblage consisting of seven haplotypes (Louisiana eastward to Taylor County, Florida, and along the Chattahoochee River drainage north to Talbot County, Georgia); (2) an eastern assemblage containing the two most common haplotypes (South Carolina through peninsular Florida) and (3) a mid-Florida assemblage consisting of seven haplotypes (along the Gulf coast from southern Levy County north to Pinellas County, then east to north of the Hillsborough River, and northeast into Orange/Oseola counties).