Plains Pocket Gopher
Encyclopedia
The plains pocket gopher (Geomys bursarius) is one of thirty-five species of pocket gopher, so named in reference to their externally located, fur-lined cheek pouches. They are burrowing animals, found in grasslands and agricultural land across the Great Plains
of North America, from Manitoba to Texas. Pocket gophers are the most highly fossorial
rodents found in North America.
of North America ranging from southern Manitoba
(Canada
), and eastern North Dakota
south to New Mexico
and Texas
in the United States
, and as far east as the extreme western parts of Indiana
. Eight subspecies are currently recognised, although some former subspecies have since been considered to be species in their own right, and are no longer included:
Fossil remains have been found as far south as Tennessee
, indicating a late Pleistocene
, early Holocene
population. This would support the hypothesis that drier environmental conditions with extensive prairies extended further south during the Late Wisconsinan glacial period, supporting populations of Geomys and other prairie species such as thirteen-lined ground squirrel
s and prairie chicken
s.
adaptations include small eyes, short, naked ears, large forefeet with heavy claws. Zygomatic
arches are widely flared, providing ample room for muscle attachment, although, unlike other pocket gophers, this species does not use the curved incisors to assist the feet in digging. The external cheek pouches, which distinguish this family from other mammals, can be turned inside-out for grooming purposes. They are used for carrying food up to 7 centimetres (2.8 in) in length and have a forward opening.
Other adaptations to a fossorial lifestyle include a low resting metabolic rate of 0.946 ml O2/g/h, and high conductance, a tolerance for low oxygen levels and high carbon dioxide levels, and a decreased water intake.
Males are significantly larger than females, with a total body length of 25 to 35 cm (9.8 to 13.8 ), compared with 21 to 32 cm (8.3 to 12.6 ) in females. The tail is short and hairless, reaching 5 to 11 cm (2 to 4.3 ) in length, and only marginally longer in males. Adults males weigh from 230 to 473 g (8.1 to 16.7 ) and females 128 to 380 g (4.5 to 13.4 ).
A long-term controlled study of tunnel excavation by plains pocket gophers found that the rate of tunnel construction ranges from a high of 2,059 cm/week of new tunnels to a low of zero over several weeks during the summer. 30 to 50 m (98.4 to 164 ) of tunnels were open at any one time. Factors affecting the size of the tunnel system appeared to be influenced more by the amount of energy needed to maintain and patrol it rather than the amount of vegetation present. Tunnels include nests, located about 50 centimetres (19.7 in) underground, and lined with grass and other plant material, as well as food caches containing grasses, roots, and tubers.
The gophers share their tunnels with numerous species of insect, including flies, scarab
and carrion beetle
s, and cave crickets. Known predators include rattlesnake
s, prairie kingsnake
s, gopher snake
s, feral cats, coyotes, foxes, badger
s, hawks, and owls.
creatures), planning daily activity around burrow temperature, where lack of air flow and high humidity lead to a decrease in evaporative and convective cooling, is likely to be important.
The gophers 72% of their time in their nests, coming above ground to search for food or mates, and for young animals to establish new burrows. Territorial and aggressive, especially in male-to-male interaction, these rodents appear to use their greatly increased sensitivity to soil vibration to maintain their solitary lifestyle. They will rarely explore burrows inhabited by other gophers, although they will sometimes investigate those that have been previously abandoned.
development.
The young are born hairless and blind, and initially weigh about 5 gram (0.17636981052556 oz). They begin to develop fur at ten days, open their eyes at three weeks, and are weaned
by five weeks of age. Although they initially move around in their mother's burrow, after weaning they quickly leave to establish burrows of their own, and reach the full adult size after about three months.
. Though pocket gophers are considered to be no more than pests by farmers and suburban lawn owners, they play active roles in soil aeration, flood control via improved drainage, and soil and plant diversity.
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
of North America, from Manitoba to Texas. Pocket gophers are the most highly fossorial
Fossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...
rodents found in North America.
Distribution
Plains pocket gophers are found throughout the Great PlainsGreat Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
of North America ranging from southern Manitoba
Manitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...
(Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
), and eastern North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
south to New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
and Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and as far east as the extreme western parts of Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...
. Eight subspecies are currently recognised, although some former subspecies have since been considered to be species in their own right, and are no longer included:
- Geomys bursarius bursarius - Canada, the Dakotas, MinnesotaMinnesotaMinnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
- Geomys bursarius illinoensis - IllinoisIllinoisIllinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
- Geomys bursarius industrius - southwestern KansasKansasKansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
- Geomys bursarius major - Texas, Oklahoma, eastern New MexicoNew MexicoNew Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
- Geomys bursarius majusculus - IowaIowaIowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
, eastern NebraskaNebraskaNebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....
and Kansas, northern MissouriMissouriMissouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It... - Geomys bursarius missouriensis - eastern Missouri
- Geomys bursarius ozarkensis - ArkansasArkansasArkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...
- Geomys bursarius wisconsinensis - western WisconsinWisconsinWisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
Fossil remains have been found as far south as Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
, indicating a late Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, early Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
population. This would support the hypothesis that drier environmental conditions with extensive prairies extended further south during the Late Wisconsinan glacial period, supporting populations of Geomys and other prairie species such as thirteen-lined ground squirrel
Thirteen-lined ground squirrel
The thirteen-lined ground squirrel , also known as the striped gopher, leopard ground squirrel, squinney, and as the leopard-spermophile in Audubon’s day, is a ground squirrel....
s and prairie chicken
Prairie Chicken
Prairie Chicken refers to several birds in the genus Tympanuchus:*Greater Prairie Chicken **Attwater's Prairie Chicken **Heath Hen **Tympanuchus cupido pinnatus...
s.
Description
G. bursarius has short fur with brown to black coloration over the upper body and lighter brown or tan fur on the underparts. Whitish hairs cover the tops of the feet while the short, tapered tail is nearly naked. FossorialFossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...
adaptations include small eyes, short, naked ears, large forefeet with heavy claws. Zygomatic
Zygomatic bone
The zygomatic bone is a paired bone of the human skull. It articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. The zygomatic is homologous to the jugal bone of other tetrapods...
arches are widely flared, providing ample room for muscle attachment, although, unlike other pocket gophers, this species does not use the curved incisors to assist the feet in digging. The external cheek pouches, which distinguish this family from other mammals, can be turned inside-out for grooming purposes. They are used for carrying food up to 7 centimetres (2.8 in) in length and have a forward opening.
Other adaptations to a fossorial lifestyle include a low resting metabolic rate of 0.946 ml O2/g/h, and high conductance, a tolerance for low oxygen levels and high carbon dioxide levels, and a decreased water intake.
Males are significantly larger than females, with a total body length of 25 to 35 cm (9.8 to 13.8 ), compared with 21 to 32 cm (8.3 to 12.6 ) in females. The tail is short and hairless, reaching 5 to 11 cm (2 to 4.3 ) in length, and only marginally longer in males. Adults males weigh from 230 to 473 g (8.1 to 16.7 ) and females 128 to 380 g (4.5 to 13.4 ).
Ecology
Plains pocket gophers prefer deep, sandy, crumbly soils to facilitate their burrowing lifestyle and their herbivorous diet of plant roots. The local vegetation is less significant than the nature of the soil, and the gophers are found in prairie grasslands, agricultural land, and even urban areas.A long-term controlled study of tunnel excavation by plains pocket gophers found that the rate of tunnel construction ranges from a high of 2,059 cm/week of new tunnels to a low of zero over several weeks during the summer. 30 to 50 m (98.4 to 164 ) of tunnels were open at any one time. Factors affecting the size of the tunnel system appeared to be influenced more by the amount of energy needed to maintain and patrol it rather than the amount of vegetation present. Tunnels include nests, located about 50 centimetres (19.7 in) underground, and lined with grass and other plant material, as well as food caches containing grasses, roots, and tubers.
The gophers share their tunnels with numerous species of insect, including flies, scarab
Scarabaeidae
The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...
and carrion beetle
Carrion beetle
Silphidae is a family of beetles that are known commonly as carrion or burying beetles. There are two subfamilies: Silphinae and Nicrophorinae. Both families feed on decaying organic matter such as dead animals. The families differ in which uses parental care and which types of carcasses they prefer...
s, and cave crickets. Known predators include rattlesnake
Rattlesnake
Rattlesnakes are a group of venomous snakes of the genera Crotalus and Sistrurus of the subfamily Crotalinae . There are 32 known species of rattlesnake, with between 65-70 subspecies, all native to the Americas, ranging from southern Alberta and southern British Columbia in Canada to Central...
s, prairie kingsnake
Lampropeltis calligaster
Lampropeltis calligaster is a species of kingsnake known commonly as the prairie kingsnake.-Geographic range:It is found throughout the midwestern and southeastern United States, from Nebraska to Virginia, Florida to Texas.- Description :...
s, gopher snake
Pituophis catenifer
Pituophis catenifer is a harmless colubrid species found in North America. Six subspecies are currently recognized, including the nominate subspecies described here. The specific name catenifer is Latin for 'chain bearing', referring to the dorsal color pattern.-Description:Adults specimens are...
s, feral cats, coyotes, foxes, badger
American Badger
The American badger is a North American badger, somewhat similar in appearance to the European badger. It is found in the western and central United States, northern Mexico and central Canada, as well as in certain areas of southwestern British Columbia.Their habitat is typified by open...
s, hawks, and owls.
Behavior
Plains pocket gophers show no seasonal change in activity, except for an increased level of activity during mating season. They do show a bimodal pattern of activity during the day with increased activity occurring from 1300-1700 and then again from 2200-0600. For a fossorial animal with a metabolically expensive lifestyle (360-3400 times as much as terrestrialTerrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
creatures), planning daily activity around burrow temperature, where lack of air flow and high humidity lead to a decrease in evaporative and convective cooling, is likely to be important.
The gophers 72% of their time in their nests, coming above ground to search for food or mates, and for young animals to establish new burrows. Territorial and aggressive, especially in male-to-male interaction, these rodents appear to use their greatly increased sensitivity to soil vibration to maintain their solitary lifestyle. They will rarely explore burrows inhabited by other gophers, although they will sometimes investigate those that have been previously abandoned.
Reproduction
Plains pocket gophers typically breed only once a year, although they may sometimes breed twice in good years or warmer climates. The breeding season varies with latitude, ranging from April to May in Wisconsin to as long as January to September in Texas. Females give birth to one to six young after a gestation period of around 30 days. However, pregnancies lasting up to 51 days have been recorded, and this variation may indicate some form of delayed fertilization, delayed implantation, or delayed zygoteZygote
A zygote , or zygocyte, is the initial cell formed when two gamete cells are joined by means of sexual reproduction. In multicellular organisms, it is the earliest developmental stage of the embryo...
development.
The young are born hairless and blind, and initially weigh about 5 gram (0.17636981052556 oz). They begin to develop fur at ten days, open their eyes at three weeks, and are weaned
Weaning
Weaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk.The process takes place only in mammals, as only mammals produce milk...
by five weeks of age. Although they initially move around in their mother's burrow, after weaning they quickly leave to establish burrows of their own, and reach the full adult size after about three months.
Conservation
Due to the widespread distribution of this species, its adaptability to suitable habitat, the lack of any major threats, and an apparently stable population, G. bursarius has a conservation status of Least ConcernLeast Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
. Though pocket gophers are considered to be no more than pests by farmers and suburban lawn owners, they play active roles in soil aeration, flood control via improved drainage, and soil and plant diversity.