Oldfield Mouse
Encyclopedia
The oldfield mouse or beach mouse (Peromyscus polionotus) is a nocturnal species of rodent
in the family Cricetidae
. It is found in the southeastern United States
on sandy beaches, in corn and cotton fields, and in hedge rows and open timber tracts. Coloration varies with geographic location: inland populations are generally fawn-colored while coastal populations are lighter or white. The mouse eats seeds, fruits, and occasionally insects, and lives and raises its three to four young in a simple burrow. Weaning occurs at 20–25 days, and females may mate at 30 days of age. Predators are those that prey on small mammals. One individual lived in captivity for about five years. The mouse is of least concern to conservationists because it is abundant and widespread, and no major threats exist for the species as a whole, but several subspecies
with small distributions are endangered or even extinct.
from central Alabama
, south-central Tennessee
, western South Carolina
, northeastern Mississippi
, and Georgia
to the Gulf Coast and through western and most of peninsular Florida
.
The mice prefer sandy fields and beaches but will choose corn and cotton fields
and occasionally hedgerows and open timber tracts. Land and beachfront development threaten habitat
. Populations of up to six per acre have been recorded.
The pinkish newborn may be washed by the mother following the last delivery and weigh between 1.1 gram. The pinnae elevate in 3–5 days, the lower incisors erupt in 6–7 days, and the eyes open in 10–16 days. Weaning is gradual and occurs over 20–25 days. First estrus may occur as early as one month and first litter at 53 days of age. The juvenile pelage is gray. At one week, the young weigh 4 g (0.141095848420448 oz), at three weeks 6 gram, and at five weeks 8 gram. The young in one study dispersed 430 m (1,410.8 ft) before establishing their homes.
because it is widespread and abundant, and there are no major threats to the species at this time (2010). It is found in many protected areas.
Of the 16 subspecies, eight coastal forms are of conservation concern. All eight subspecies have restricted distributions and are threatened by habitat loss and associated pressures due to tourism and land development.
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
in the family Cricetidae
Cricetidae
The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, and New World rats and mice...
. It is found in the southeastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
on sandy beaches, in corn and cotton fields, and in hedge rows and open timber tracts. Coloration varies with geographic location: inland populations are generally fawn-colored while coastal populations are lighter or white. The mouse eats seeds, fruits, and occasionally insects, and lives and raises its three to four young in a simple burrow. Weaning occurs at 20–25 days, and females may mate at 30 days of age. Predators are those that prey on small mammals. One individual lived in captivity for about five years. The mouse is of least concern to conservationists because it is abundant and widespread, and no major threats exist for the species as a whole, but several subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
with small distributions are endangered or even extinct.
Distribution and habitat
Peromyscus polionotus occurs only in the southeastern United StatesSoutheastern United States
The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....
from central Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, south-central 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...
, western South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
, northeastern Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...
, and Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
to the Gulf Coast and through western and most of peninsular Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
.
The mice prefer sandy fields and beaches but will choose corn and cotton fields
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
and occasionally hedgerows and open timber tracts. Land and beachfront development threaten habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
. Populations of up to six per acre have been recorded.
Description
The mouse has fawn-colored upperparts and gray to white underparts through most of its range but on white sandy beaches the mouse is light or even white. Inland populations are darker and smaller with shorter tails that are dusky above and white below. General body and tail color may vary slightly depending upon geographical location.| Measurements (20 adults from Alabama, Florida, and Georgia) | |
|---|---|
| Length | 127 mm (5 in) 122 millimetre |
| Tail | 47 mm (1.9 in) 40 millimetre |
| Hind foot | 16.5 mm (0.649606299212598 in) 15 millimetre |
| Weight | 8 gram |
| Diploid number | 48 |
| Tooth formula | = 16 |
Diet
P. polionotus are omnivores and the principal diet is seasonal seeds of wild grasses and forbs but blackberries, acorns, and wild pea may be consumed. Insects consumed include beetles, leaf hoppers, true bugs, and ants. Vertebrates are consumed. Beach populations will consume the fruits and wind-deposited seeds of sea oats and sea rocket and will feed on invertebrates when seeds are scarce.Shelter
The beach mouse burrows and leaves mounds of earth around the burrow entrance. The burrow slopes down from the entrance for a space then levels off with a nest at its end. A branch of the burrow may extend above the nest to just a few centimeters below the surface as an emergency exit. Should the burrow be disturbed, the mouse will "explode" through the sand via the exit and dash off. The mice will close any burrows in heavy rains should flood threaten. Spiders, snakes, and other species may move into a burrow.Reproduction
The mice are monogamous. Gestation is 23–24 days, possibly 25–31 if the mother is still lactating from a previous litter. Mean litter size is 3–4. When birth is imminent, the female assumes a crouching position and may rise to a more erect position as each juvenile is born. She may aid the birth by gently pulling on the young with her forefeet, as one mouse has been observed doing. The placenta may be removed in the same manner. She then eats it. The umbilical cord is broken by pulling or chewing or when the placenta is consumed. She may stretch and groom between deliveries. Births usually occur in the daytime and usually over several minutes or even an hour.The pinkish newborn may be washed by the mother following the last delivery and weigh between 1.1 gram. The pinnae elevate in 3–5 days, the lower incisors erupt in 6–7 days, and the eyes open in 10–16 days. Weaning is gradual and occurs over 20–25 days. First estrus may occur as early as one month and first litter at 53 days of age. The juvenile pelage is gray. At one week, the young weigh 4 g (0.141095848420448 oz), at three weeks 6 gram, and at five weeks 8 gram. The young in one study dispersed 430 m (1,410.8 ft) before establishing their homes.
| Reproduction | |
|---|---|
| Sexual maturity (female) | 30 days |
| Gestation | 23–24 days |
| Litter size | 3–4 (viviparous) |
| Weight at birth | 1.1 gram |
| Weaning | 20–25 days |
| Adult weight | 8 gram |
Survival
Presumed predators are those that prey upon small mammals including house cats. Parasites found in mice from Florida were six species of nematodes, one each of trematodes and acanthocephalans, and two of fleas. One mouse survived in captivity 5.5 years.Conservation
The IUCN lists the species as 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...
because it is widespread and abundant, and there are no major threats to the species at this time (2010). It is found in many protected areas.
Of the 16 subspecies, eight coastal forms are of conservation concern. All eight subspecies have restricted distributions and are threatened by habitat loss and associated pressures due to tourism and land development.
- P. p. decoloratus is Extinct;
- P. p. trissyllepsis (Perdido Key beach mousePerdido Key Beach MouseThe Perdido Key beach mouse is an endangered subspecies of the oldfield mouse. It is found on Perdido Key, Florida. The small white and gray mouse, weighing only , blends in well with the white quartz sand of northern Gulf coast beaches.-Diet:Dune plants are the primary source of food for the...
) is Critically Endangered; - P. p. allophrys (Choctawatchee beach mouse), P. p. ammobates (Alabama beach mouseAlabama Beach MouseThe Alabama Beach Mouse is a federally endangered species which lives along the Alabama coast.The range of the Alabama beach mouse historically included much of the Fort Morgan Peninsula on the Alabama Gulf coast and extends from Ono Island to Fort Morgan.Coastal residential and commercial...
), P. p. peninsularis (St. Andrews beach mouse), and P. p. phasma (Anastasia Island beach mouseAnastasia Island Beach MouseThe Anastasia Island beach mouse is a subspecies of the oldfield mouse of the southeastern United States. It occurs in the sand dunes of Florida and Alabama beaches...
) are considered Endangered; - P. p. leucocephalus (Santa Rosa beach mouse), and P. p. niveiventris (Southeastern beach mouse) are Near Threatened.