Masticophis flagellum

Nicholson (2025) is following Myers et al. (2017) in recognizing Masticophis as a genus. Using molecular and morphological data, O’Connell and Smith (2018) recognized populations west of the Cochise Filter Barrier (the boundary between the Sonoran and Chihuahuan Deserts) as a distinct species, M. piceus, and recognized the named subspecies as evolutionary lineages within each species, though they did not evaluate the subspecies M. f. ruddocki. Myers et al. (2017, 2019) also found these two lineages meeting at the Cochise Filter Barrier using mtDNA and genome-scale data (Nicholson 2025).

Nicholson (2025) modified the English name to "Common Coachwhip" to differentiate it from other species called “Coachwhips.”

This species has a large range, many recent occurrences, and populations appear stable.

This species occurs in the southern United States from North Carolina, south to Florida and west through Kansas and southern Nebraska to Arizona, and in north-central Mexico south to Queretaro (Wilson 1973; Grismer 2002; RARECAT 2025). Recent taxonomic updates places the elevated subspecies piceus west of west of the Cochise Filter Barrier, or the boundary between the Sonoran and Chihuahuan Deserts, however there is another subspecies, ruddocki, in central California that was not examined and since it is still considered this species, California is still part of its range (Nicholson 2025; Southwestern Center for Herpetological Research 2025).

This species is known from at > 2800 occurrences using a 1 km separation distance and records from 1995-2026 (RARECAT 2025).

The scope and severity of threats to this species are unknown, but this snake occurs in semi-agricultural areas but generally not in areas with extensive, intensive cultivation (Hammerson 1999). Plastic netting such as used to exclude birds from fruit trees (and as components of erosion control blankets) is a potentially lethal entanglement hazard to this species and to other wildlife (Stuart et al. 2001).