Peromyscus polionotus
| Oldfield Deermouse
(Peromyscus polionotus) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Myomorphi |
| Superfamily: | Muroidea |
| Family: | Cricetidae |
| Subfamily: | Neotominae |
| Tribe: | Peromyscini |
| Genus: | Peromyscus |
| Binomial details | |
| Peromyscus polionotus (J. A. Wagner, 1843) | |
| Other resources | |
| Full taxonomic details at MDD | |
Description
From Best & Hunt (2020): "This is a small deermouse with a relatively short tail that is usually 55–65% of the length of head and body combined. Color is variable and is usually similar to that of the substrate. Individuals in fields or woods are pale brown or brownish-gray with a slightly darker mid-dorsal band and individiuals from populations near the coast (often referred to as beach mice) are paler and may be nearly white. Underparts and feet are white. The tail is bicolored (or white in some beach mice)."
Museum type specimens
Holotype: MCZ:Mamm:BANGS-5925. Peromyscus polionotus. Male. Hursman's Lake, Screven County, Georgia. Doral view. 
Holotype: MCZ:Mamm:BANGS-5925. Peromyscus polionotus. Male. Hursman's Lake, Screven County, Georgia. Ventral view.
External measurements
Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.
| Part of range | Reference | Total length | Tail length | Hindfoot length | Ear length | Mass |
|---|---|---|---|---|---|---|
| Alabama | Best & Dusi (2014) | 118 (109–132) (n=25) | 45 (32–54) (n=25) | 17 (15–20) (n=25) | 14 (10–15) (n=25) | 13.0 (10.1–17.6) (n=12) |
| Carolinas, Virginia, Maryland | Webster et al. (1985) | 122–134 | 40–52 | 14–18 |
Color variation
Peromyscus polionotus shows wide variation in color of pelage across its geographic range.
From Kaufman (1974): "Dark brown forms and paler brown forms are characteristic of northern-inland populations and southern-mainland populations, respectively, whereas beach forms exhibit the palest pelage colors. An exception to this pattern of distribution is the presence of a light brown phenotype (an autosomal recessive trait; Dawson et al., 1969) as well as the normal dark brown phenotype of P. polionotus found on the Atomic Energy Commission's Savannah River Plant in South Carolina."
NEON06RXQ. Oldfield Deermouse (Peromyscus polionotus). The Jones Center At Ichauway, Baker County, Georgia. Collected 23 August 2022. Individual is a scrotal male and transitioning from juvenile pelage (juvenile gray on head) to adult pelage. 
NEON0E1EI. Oldfield Deermouse (Peromyscus polionotus). Adult female. The Jones Center At Ichauway, Baker County, Georgia. Collected 23 September 2025. 
Holotype: MCZ:Mamm:BANGS-5925. Peromyscus polionotus. Male. Hursman's Lake, Screven County, Georgia. Doral view. 
Holotype: MCZ:Mamm:BANGS-5925. Peromyscus polionotus. Male. Hursman's Lake, Screven County, Georgia. Ventral view. 
NEON06RXQ. Peromyscus polionotus. Dorsal view of the skull of Peromyscus polionotus. Adult male. The Jones Center At Ichauway, Baker County, Georgia. 
NEON06RXQ. Peromyscus polionotus. Ventral view of the skull of Peromyscus polionotus. Adult male. The Jones Center At Ichauway, Baker County, Georgia. 
NEON06RXQ. Peromyscus polionotus. Lateral view of the skull of Peromyscus polionotus. Adult male. The Jones Center At Ichauway, Baker County, Georgia. 
NEON06RXQ. Peromyscus polionotus. Dorsal view of the lower jaw of Peromyscus polionotus. Adult male. The Jones Center At Ichauway, Baker County, Georgia. 
NEON06RXQ. Peromyscus polionotus. Upper incisors of Peromyscus polionotus. Adult male. The Jones Center At Ichauway, Baker County, Georgia. As in all Peromyscus, the upper incisors lack grooves. -
Adult Oldfield Deermouse (Peromyscus polionotus) -
Adult Cotton Deermouse (Peromyscus gossypinus) -
Adult White-footed Deermouse (Peromyscus leucopus) -
Oldfield Deermouse (Peromyscus polionotus) -
Eastern Harvest Mouse (Reithrodontomys humulis) -
The upper incisors of the Oldfield Deermouse (Peromyscus polionotus) are smooth and lack grooves. -
Skull of the Fulvous Harvest Mouse (Reithrodontomys fulvescens) showing grooved upper incisors, which is characteristic of the genus.
Skull
Similar species
Comparison with other Peromyscus species
Peromyscus polionotus is small member of the genus Peromyscus and is generally not easily confused with the Cotton Deermouse (Peromyscus gossypinus) and the White-footed Deermouse (Peromyscus leucopus), which are sympatric, but much larger species.
Comparison with Reithrodontomys humilis
Peromyscus polionotus is small mouse that may be confused with the small Eastern Harvest Mouse (Reithrodontomys humulis). However, members of the genus Reithrodontomys have grooved upper incisors, whereas members of the genus Peromyscus do not not have grooved upper incisors.
References
Best TL, Dusi JL. 2014. Mammals of Alabama (Vol. 4). Tuscaloosa (AL, USA): University Alabama Press.
Best TL, Hunt JL. 2020. Mammals of the southeastern United States. Tuscaloosa (AL, USA): University Alabama Press.
Dawson WD, Smith MH, Carmon JL. 1969. A third independent occurrence of the brown mutant in Peromyscus. Journal of Heredity 60:286-28.
Kaufman DW. 1974. Adaptive coloration in Peromyscus polionotus: experimental selection by owls. Journal of Mammalogy 55(2): 271-283.
Wagner JA. 1843. Bericht über die Leistungen in der Naturgeschichte der Säugthiere während des Jahres 1842. Archiv für Naturgeschichte 9(2):1-67.
Webster WD, Parnell JF, Biggs WC. 1985. Mammals of the Carolinas, Virginia, and Maryland. Chapel Hill (NC, USA): University of North Carolina Press.