Microtus ochrogaster
| Prairie Vole
(Microtus ochrogaster) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Myomorphi |
| Superfamily: | Muroidea |
| Family: | Cricetidae |
| Subfamily: | Arvicolinae |
| Tribe: | Microtini |
| Genus: | Microtus |
| Subgenus: | Pitymys |
| Binomial details | |
| Microtus ochrogaster (J. A. Wagner, 1843) | |
Description
From Stalling (1990): "The pelage is usually grayish-brown above, with a mixture of black and brownish-yellow tips on longer hairs giving the dorsum a grizzled appearance (Mumford and Whitaker, 1982); however, the dorsum may be dark bister (Hall, 1981). Sides are paler than dorsum; venter is neutral gray or washed with whitish or pale cinnamon; tail is sharply bicolored."
From Armstrong et al. (2010): "This is a fairly large vole with a gray-brown to reddish brown dorsum and a pale buffy to grayish buff belly."
From Best & Hunt (2020): "The prairie vole is a medium-sized vole with a short tail. Dorsal pelage is grayish-brown with black and brownish-yellow tips, contributing to a grizzled look. Sides are somewhat paler. The ventrum is grayish or tan, sometimes with whitish or reddish coloring. The tail is bicolored. Ears are nearly concealed by fur."
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) | 142 (124–157) (n=15) | 31 (26–37) (n=15) | 19 (16–26) (n=15) | 9 (6–14) (n=10) | 41.7 (26.7–59.0) (n=15) |
| Colorado | Armstrong et al. (2010) | 150–190 | 33–45 | 20–23 | 11–15 | 50–75 |
| Minnesota | Hazard (1982) | 119–166 | 27–46 | 15.5–22 | 9–14 | 16.8–49.1 |
| Nebraska | Johnsgard (2020) | 110–188 | 33–45 | 30–70 | ||
| North Dakota | Seabloom et al. (2020) | 141 | 34 | 18 | 12 | 28 |
| Texas | Schmidly & Bradley (2016) | 146 | 34 | 20 | 30–50 |
Variation
This section shows some of the color variation present in Microtus ochrogaster. The location is provided for reference only. The individual shown does not necessarily represent the only color variant within the local population.
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Kansas, Riley County -
Kansas, Riley County -
Kansas, Riley County -
juvenile, Kansas, Riley County
Skull
From Armstrong et al. (2010): The skull is similar to others of the genus, although the third lower molar has 3 loops of dentine and no closed triangles. The last upper molar has 4 dentine lakes somewhat similar to the pattern of the sagebrush voles [Lemmiscus curtatus]. The posterior margins of the premaxillary extend beyond the margins of the nasals.
Similar species
From Stalling (1990): "Prairie voles may be distinguished from other arvicoline rodents (Hall, 1981) by their third lower molar that has three transverse loops and no closed triangles. Their third upper molar has two closed triangles. Their fur is long, coarse, and typically grayish brown. The tail usually is 26 mm in length."
For Colorado, from Armstrong et al. (2010): "The buffy venter separates it readily from other voles in Colorado, all of which have grayish or silvery gray bellies."
From Henterley et al. (2011): "Microtus ochrogaster typically have five plantar tubercles and a tail length:hind foot length ratio >2, while in M. pennsylvanicus the typical number of plantar tubercles is six with a tail length:hind foot length ratio >2... Although pelage and number of plantar tubercles are the primary phenotypic characters used for distinguishing between Microtus ochrogaster and M. pennsylvanicus in the field, we found that, in our hands, they were not completely reliable when compared to the species diagnostic avpr1a genotypes of individuals."
From Best & Hunt (2020): "Prairie voles occasionally are difficult to distinguish from meadow voles [Microtus pennsylvanicus]. Prairie voles have relatively shorter tails, and they have cusps on the third upper molar that form two closed triangles between the anterior and posterior loops, while meadow voles have three such triangles."
For Kentucky, from Everson et al. (2023): "Two other Microtus species live in the eastern United States—the woodland vole M. pinetorum and the rock vole M. chrotorrhinus—which are easily recognized by their unique habitats (deciduous forests and rocky areas, respectively) and by the short tail length of M. pinetorum and the yellow rostrum of M. chrotorrhinus. Microtus ochrogaster and M. pennsylvanicus, on the other hand, often occupy the same habitats and are exceptionally difficult to distinguish based on external characteristics (Adams et al. 2017). While mammalogists often rely on external measurements and pelage coloration to distinguish between species, our results suggest that these characteristics do not reliably distinguish the vole species M. ochrogaster and M. pennsylvanicus in our study region [Kentucky] where they occur in sympatry. Despite statistical differences between six external traits, too much measurement range overlap occurred for reliable field identification (Table 1). Ventral fur coloration was also not a reliable field trait for distinguishing these two species in our study region. While M. ochrogaster is described as having yellow or buffy ventral fur and M. pennsylvanicus as having gray or silvery ventral fur, we found most individuals in Kentucky to have intermediate buffy-gray coloration. Thus, while ventral fur color might be a useful character in other parts of the their ranges, it cannot effectively be used to identify the two species where they co-occur in Kentucky. Our results align with previous studies that demonstrated limited utility of these external morphological characteristics in distinguishing the two species (DeCoursey 1957; Henterly et al. 2011). However, we acknowledge that this study did not consider mammae count, another external trait often used in species identification; M. ochrogaster is known to have six mammae, whereas M. pennsylvanicus has eight. This character may well be useful for species identification in our study region. [Additionally] our results suggest that molar cusp pattern is the most accurate morphological character used to distinguish M. ochrogaster and M. pennsylvanicus. We found that 94% of individuals that were assigned to species based on dentition were also recovered within their respective mitochondrial clade."
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Range of Microtus ochrogaster and Microtus pennsylvanicus.
Molecular identification
Form Henterley et al. (2011): For differentiation of Microtus ochrogaster and Microtus pennsylvanicus: "Genomic DNA was extracted using DNeasy kits (Qiagen, Valencia,CA) and the avpr1a genotypes of voles were determined by polymerase chain reaction (PCR), with primers specifically designed to amplify the microsatellite region of the avpr1a gene in prairie voles (Hammock and Young, 2005). Our avpr1a genotyping procedure was identical to that followed by Solomon et al. (2009), who confirmed that these primers amplified the targeted region of the avpr1a gene by sequencing the resulting PCR product and comparing the sequence to the prairie vole avpr1a gene sequence published in GenBank. Previous studies using the same primers as in our investigation have demonstrated that PCR amplification of this microsatellite region of the avpr1a gene in known Microtus pennsylvanicus yields PCR fragments that are 200–300 bp, while in known M. ochrogaster the resultant PCR fragments are 600–800 bp (Young et al., 1999; Fink et al., 2006).
References
Adams NE, Inoue K, Solomon NG. 2017. Range-wide microsatellite analysis of the genetic population structure of prairie voles (Microtus ochrogaster). The American Midland Naturalist 177(2):183-199.
Armstrong DM, Fitzgerald JP, Meaney CA. 2010. Mammals of Colorado, Second Edition. Denver (CO, USA): University Press of Colorado.
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.
DeCoursey Jr GE. 1957. Identification, ecology and reproduction of Microtus in Ohio. Journal of Mammalogy 38(1):44-52.
Everson KM, McGinnis RC, Burdine OP, Huddleston TR, Hylick TM, Keith AL, Moore SC, O’Brien AE, Vilardo AL, Krupa JJ. 2023. Disentangling morphology and genetics in two voles (Microtus pennsylvanicus and M. ochrogaster) in a region of sympatry. Journal of Mammalogy 104(3):532-545.
Fink S, Excoffier L, Heckel G. 2006. Mammalian monogamy is not controlled by a single gene. Proceedings of the National Academy of Sciences 103(29):10956-10960.
Hall ER. 1981. The mammals of North America. Second edition. John Wiley & Sons, New York.
Hazard EB. 1982. The mammals of Minnesota. Minneapolis (MN, USA): University of Minnesota Press.
Henterly AC, Mabry KE, Solomon NG, Chesh AS, Keane B. 2011. Comparison of morphological versus molecular characters for discriminating between sympatric meadow and prairie voles. The American Midland Naturalist 165(2):412-420.
Johnsgard PA. 2020. Wildlife of Nebraska: a natural history. Lincoln (NE, USA): University of Nebraska Press.
Mumford RE, Whitaker Jr JO. 1982. Mammals of Indiana. Indiana University Press, Bloomington, 537 pp.
Naughton D. 2012. The natural history of Canadian mammals. Toronto (ON, CA): University of Toronto Press.
Schmidly DJ, Bradley RD. 2016. The mammals of Texas. Austin (TX, USA): University of Texas Press.
Seabloom R, Hoganson JW, Jensen WF. 2020. The mammals of North Dakota. Fargo (ND, USA): North Dakota State University Press.
Stalling DT. 1990. Microtus ochrogaster. Mammalian Species (355): 1-9.
Wagner JA. 1843. Heft 117, Heft 118. Pp. 473–614 in Wagner, J.A. Die Säugthiere in Abbildungen nach der Natur mit Beschreibungen. Supplementband. Dritte Mittheilung: Die Beutelthiere und Nager (erster Abschnitt). Erlangen, Die Säugthiere in Abbildungen nach der Natur, 614 pp.
Young LJ, Hammock EA. 2007. On switches and knobs, microsatellites and monogamy. Trends in Genetics 23(5):209-212.