Sigmodon hispidus
Hispid Cotton Rat
(Sigmodon hispidus) | |
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Range | |
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Taxonomic classification | |
Order: | Rodentia |
Suborder: | Supramyomorpha |
Infraorder: | Myomorphi |
Superfamily: | Muroidea |
Family: | Cricetidae |
Subfamily: | Sigmodontinae |
Tribe: | Sigmodontini |
Genus: | Sigmodon |
Subgenus: | Sigmodon (subgenus) |
Binomial details | |
Sigmodon hispidus Say & Ord, 1825 |
Description
From Hoffmeister (1986): "A Sigmodon of medium size; hind foot usually less than 32 mm; tail usually less than 110 mm; pelage similar to that in S. arizonae; skull medium to large size; distance between parietal and squamosal crests less than 3.2 mm; length of squamosal crest usually less than 7.0 mm; occipital "shield" angled dorsally; anterior spine on infraorbital plate blunt and broad; presphenoid narrow; palatine foramina rounded posteriorly; antero-venral border of foramen magnum rounded."
From Best & Hunt (2020): "A medium-sized rat with a dorsum that is grayish-brown to dark brown to blackish and that is interspersed with paler hairs giving a grizzled appearance. Ventral pelage is usually grayish. Eyes are dark, and ears are dark and partially hidden in pelage. The tail is shorter than the length of head and body combined, indistinctly bicolored, scaly, and sparsely haired."
From Armstrong et al. (2010): "Hispid cotton rats have harsh, dark-colored pelage. Dorsal color is blackish brown interspersed with yellowish to buffy hairs. The underparts are paler in color, tending toward gray. The tail is sparsely haired, revealing the scales underneath. Length of the tail is less than that of the head and body. The ears are small but well haired."
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 |
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Alabama | Best & Dusi (2014) | 233 (135–300) (n=40) | 97 (82–114) (n=40) | 30 (26–35) (n=40) | 18 (15–21) (n=18) | 95.9 (70.8–145.0) (n=16) |
Arizona (southeastern) | Hoffmeister (1986) | males: 225–266 (n=5); females:228–269 (n=5) | males: 102–109 (n=5); females: 88–119 (n=5) | males: 29–32 (n=5); females: 27–30 (n=5) | males: 17–20 (n=5); females: 18–20 (n=5) | |
Arizona (vicinity of Yuma) | Hoffmeister (1986) | males: 226–311(n=14); females: 210–319 (n=8) | males: 99–132 (n=14); females: 94–130 (n=8) | males: 31–34 (n=14); females: 29–32 (n=8) | males: 18–20 (n=14); females: 17–21 (n=8) | |
California | Jameson & Peeters (2004) | 224–365 | 81–166 | 28–41 | 16–24 | 100–225 |
Carolinas, Virginia, Maryland | Webster et al. (1985) | 230–320 | 80–140 | 112–245 | ||
Colorado | Armstrong et al. (2010) | 224–265 | 81–166 | 28–35 | 16–24 | 100–225 |
Texas | Schmidly & Bradley (2016) | 270 | 110 | 31 | 80–150 | |
Virginia | Linzey (1998) | 225–325 | 80–135 | 112–225 |
Similar species
From Hoffmeister (1986): "S. hispidus differs from S. fulviventer as follows: underparts silvery or grayish rather than buffy or fulvous; tail bicolored, lighter below than above; tops of hind feet silvery or grayish rather than buffy; hind feet and ears averaging longer; preoptic foramen usually absent; nasals usually truncate or notched rather than tapered posteriorly. S. hispidus differs from S. ochrognathus as follows: no orangeish or ochraceous nose ring and eye ring but color in these areas nearly same as that of sides and back; hind foot longer, usually 29 mm or more, but may be slightly smaller in some females; ears and tail longer; skull larger, especially for comparable ages and sexes; posterior border of interparietal without a median notch formed by supraoccipital; base of baculum gradually curved and broad."
Skull characters
From Armstrong et al. (2010): "Molars are rooted and high-crowned. Their occlusal surface has large, flattened cusps (sometimes described as "lozenge-shaped") arranged in a sigma-shaped pattern (hence the generic name). The skull is long, narrow, and stout with well-developed supraorbital (temporal) ridges. The infraorbital foramen is prominent, and the infraorbital plate of the zygomatic arch has a pronounced, blunt, spinelike, anterior projection."
References
Armstrong DM, Fitzgerald JP, Meaney CA. 2010. Mammals of Colorado, Second Edition. Denver (CO, USA): University Press of Colorado.
Best, T.L., & Hunt, J.L., 2020. Mammals of the southeastern United States. University Alabama Press.
Ceballos G, editor. 2014. Mammals of Mexico. Baltimore (MD, USA): Johns Hopkins University Press.
Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.
Jameson EW, Peeters HJ. 2004. Mammals of California (No. 66). Berkeley (CA, USA): University of California Press.
Linzey DW. 1998. The mammals of Virginia. McDonald & Woodward Publishing.
Say T, Ord G. 1825. Description of a new species of Mammalia, whereon a genus is proposed to be founded. Journal of the Academy of Natural Sciences of Philadelphia 4:352-356.
Schmidly DJ, Bradley RD. 2016. The mammals of Texas. Austin (TX, USA): University of Texas Press.
Webster WD, Parnell JF, Biggs WC. 1985. Mammals of the Carolinas, Virginia, and Maryland. Chapel Hill (NC, USA): University of North Carolina Press.