The hispid cotton rat (Sigmodon hispidus) is a rodent species long thought to occur in parts of South America, Central America, and southern North America. However, recent taxonomic revisions, based on mitochondrial DNA sequence data, have split this widely distributed species into three separate species (S. hispidus, S. toltecus, and S. hirsutus). The southern edge of the S. hispidus distribution is likely near the Rio Grande, where it meets the northern distribution of S. toltecus (formerly S. h. toltecus). The northern extent of S. hispidus distribution is to the Platte River in Nebraska and from Arizona to Virginia. Adult size is total length 202–340 mm (7.9-13 in); tail 87–122 mm (3.4-4.8 in), frequently broken or stubbed; hind foot 29–35 mm (1-1.3 in); ear 16–20 mm (0.6-0.9 in); mass