Geomys bursariusplains pocket gopher

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Geographic Range

Geomys bursarius is found west of the Mississippi River to the Rocky Mountains, and north from Texas and northeastern Mexico, through the Great Plains and to the Canadian border. (Paradiso, 1975)

Habitat

Geomys bursarius is found in open to sparsely wooded areas. It prefers deep, sandy, crumbly soils, and its distribution tends to be limited by soil type. Because of this preference, the distribution of Geomys is often patchy, closely tracking the local soils (Heaney and Timm 1985; Paradiso 1975).

Physical Description

Geomys bursarius has short fur, which can vary from a pale brown to black, and is usually paler on the underside (Paradiso 1975). As in other members of the family Geomyidae, the skull of G. bursarius is heavily reinforced, and it has strong jaw muscles. The tail is long, with little hair (MacDonald 1984). Foreclaws are large and grow rapidly. The body is 187-357 mm long, and the tail is 51-107 mm long (Whitaker 1997). (MacDonald, 1984; Whitaker, 1997)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    300 to 450 g
    10.57 to 15.86 oz
  • Range length
    187 to 357 mm
    7.36 to 14.06 in
  • Average basal metabolic rate
    0.769 W
    AnAge

Reproduction

The sex ratio of pocket gophers is often skewed, with 3-4 times as many females as males. Male reproductive success is highly variable, with a small number of the males mating with a majority of the females (MacDonald 1984). Females can reach sexual maturity in the year of their birth, but males do not until the following year (MacDonald 1984). Mating begins in very early spring, depending on local climatic conditions. Young are born in early spring through the end of summer in the southern U.S., with the majority of offspring born April-July. There are one to three offspring in a litter. The gestation period is 18-19 days, and the young will stay with the mother for about 2 months (Paradiso 1975).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring
    4
    AnAge
  • Average gestation period
    51 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    91 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    91 days
    AnAge

Lifespan/Longevity

Behavior

These animals are solitary and territorial. Males leave their burrows in early spring to mate, but then return to their territory. Territories of males are generally larger than those of females, and boundaries may be contiguous (MacDonald 1984). Pocket gophers fight other pocket gophers unknown to them, and there is male-male aggression during the breeding season (MacDonald 1984; Paradiso 1975). Burrows are relatively shallow in the summer (20-30 cm - Whitaker 1997), and somewhat deeper in the winter. Pocket gopher burrows can be found by piles of earth which are left nearby as the burrow is excavated.

Communication and Perception

Food Habits

Geomys bursarius is herbivorous and feeds mainly on underground roots or tubers (Paradiso 1975). It also occasionally forages for vegetation above ground (MacDonald 1984). These animals rarely drink water, as they apparently obtain sufficient water from their food (Paradiso 1975).

Economic Importance for Humans: Positive

The burrows of pocket gophers can help to aerate soil, and also provide some flood control by improving drainage (Paradiso 1975).

Economic Importance for Humans: Negative

Pocket gophers are considered pests to agriculture, as well as in suburban lawns (Paradiso 1975).

Conservation Status

Geomys bursarius is common within its range.

Contributors

Kate Teeter (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

Heaney, L., R. Timm. 1985. Morphology, genetics, and ecology of pocket gophers (genus Geomys) in a narrow hybrid zone. Biological Journal of the Linnean Society, 25: 301-317.

MacDonald, D. 1984. The Encyclopedia of Mammals. New York: Facts on File Publications.

Paradiso, J. 1975. Walker's Mammals of the World, 3rd edition. Baltimore: Johns Hopkins University Press.

Whitaker, J. 1997. National Audubon Society Field Guide to North American Mammals. New York: Alfred A. Knopf.