Oldfield mouse
Species of rodent
From Wikipedia, the free encyclopedia
The oldfield mouse, oldfield deermouse[3] or beach mouse (Peromyscus polionotus) is a nocturnal species of rodent in the family Cricetidae. It is a species of the genus Peromyscus, a closely related group of New World mice often called "deermice", that primarily eats seeds. It lives in holes throughout the Southeastern United States in beaches and sandy fields. Predators to these mice include birds and mammals. In 2016, these mice were in the least concern category on the IUCN Red List with certain subspecies classified as extinct, critically endangered, endangered or near threatened.
| Oldfield mouse | |
|---|---|
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| Oldfield mouse at the beach, Alabama | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Cricetidae |
| Subfamily: | Neotominae |
| Genus: | Peromyscus |
| Species: | P. polionotus |
| Binomial name | |
| Peromyscus polionotus (Wagner, 1843) | |
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| native range | |
| Synonyms[3] | |
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List
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Distribution and habitat
The oldfield mouse occurs only in the southeastern United States, ranging from Florida to Tennessee.[1] They primarily live in beaches and sandy fields.[4]
Description
The mouse has fawn-colored upperparts and grey 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.[4]
| Measurements (20 adults from Alabama, Florida, and Georgia)[4] | ||
|---|---|---|
| Statistic | Average | Range |
| Length | 127 mm (5.0 in) | 122–138 mm (4.8–5.4 in) |
| Tail | 47 mm (1.9 in) | 40–51 mm (1.6–2.0 in) |
| Hind foot | 16.5 mm (0.65 in) | 15–18 mm (0.59–0.71 in) |
| Weight | 8–19 g (0.28–0.67 oz) | |
| Diploid number | 48 | |
| Tooth formula | 1.0.0.31.0.0.3 = 16 | |
Behavior
The mouse is primarily nocturnal.[1] Oldfield mice construct elaborate burrow systems with entrance tunnels, nest chambers, and escape routes.[5]
Diet
P. polionotus is omnivorous and the principal diet is seasonal seeds of wild grasses and forbs, but blackberries, acorns, and wild peas may be consumed.[1][6][7]
Shelter
These mice dig holes in earth to create homes. Spiders, snakes, and other animals may move into a burrow.[8]
Reproduction
| Reproduction[9] | |
|---|---|
| Sexual maturity (female) | 30 days |
| Gestation | 23–24 days |
| Litter size | 3–4 (viviparous) |
| Weight at birth | 1.1–2.2 g (0.039–0.078 oz) |
| Weaning | 20–25 days |
| Adult weight | 8–10 g (0.28–0.35 oz) |
Survival
Birds and mammals prey upon the oldfield mouse. Various types of parasites can effect oldfield mice, with nematodes being the main ones.[10] One mouse survived in captivity for 5.5 years.[11]
Conservation
In 2010, the beach mouse was in the least concern category on the IUCN Red List. For the beach mouse's subspecies, out of sixteen known, one is extinct, one was listed critically endangered, four endangered and two near threatened.[1]
Under the Endangered Species Act of 1973, the following beach mice are protected as endangered or threatened subspecies:
- Southeastern beach mouse (P. p. niveiventris) – Threatened[12][13]
- Anastasia Island beach mouse (P. p. phasma) – Endangered[13][14]
- Alabama beach mouse (P. p. ammobates) – Endangered[15][16]
- Perdido Key beach mouse (P. p. trissyllepsis) – Endangered[16][17]
- Choctawhatchee beach mouse (P. p. allophrys) – Endangered[16][18]
- St. Andrew beach mouse (P. p. peninsularis) – Endangered[19][20]
The pallid beach mouse (P. p. decoloratus) is presumed extinct.[21][22] The Santa Rosa beach mouse (P. p. leucocephalus)[23] is listed as critically imperiled by NatureServe.[24]
Predation
In Florida, beach mice may be eaten by some growth stage of invasive snakes such as Burmese pythons, reticulated pythons, Southern African rock pythons, Central African rock pythons, boa constrictors, yellow anacondas, Bolivian anacondas, dark-spotted anacondas, and green anacondas.[25]
