The northern sheep frog (Hypopachus variolosus) is native to Central America, Mexico, and extreme south Texas, United States. It occurs in the lowlands from Sonora, Mexico, to northern Costa Rica on the Pacific coast, and south Texas to Honduras on the Gulf of Mexico and Caribbean coasts. The sheep frog inhabits semiarid thornscrub, savannas, pasturelands, and open woodlands, as well as more humid, moist forest in the canyons, basins, foothills, and lower elevations of mountains slopes. It is a fossorial, burrowing frog that is seldom seen on the surface except at night after heavy rains when they emerge to breed. The sheep frog gets its name from its distinctive call that resembles a sheep's bleat. It is a diet specialist primarily feeding on termites and ants. The sheep frog is a small, stout frog with short legs, ranging about 2.5-3.8 cm, with females growing larger than the males. The dorsal color ranges from tan, to reddish-tan, to various shades of brown with irregular black flecks or spots, which may be extensive on some individuals, or absent on others. An orange, red, or yellowish mid-dorsal stripe, running from the snout to the vent is present on some specimens, but may by absent, vague, or fragmented on others. It is a common species in some areas of its range, but it is uncommon in the US and listed as a threatened species in the state of Texas. Etymology and nomenclature Hypopachus is derived from two compounded Greek words: hypo = under, beneath, lesser; and pachos = thickness, implying fat or thick. The specific epithet variolosus is derived from the Latin word vario or variola = to variegate or variegated; and osus = full of or prone to, referencing the markings on the frogs belly. The standardized common names of sheep frog (singular) for the species Hypopachus variolosus, and sheep frogs (plural) for the genus Hypopachus, have long been established and are in wide usage. However, on Wikipedia, a previously established article on the genus Hypopachus has monopolized the common name sheep frogs and does not recognize the singular and plural forms of the same name (e.g. sheep frog, sheep frogs) as two separate pages, so the name northern sheep frog, which has some limited usage, has been applied here. Some other names used early in the 20th century, before the establishment of standardized common names include, Mexican narrow-mouthed toad, Taylor's toad, and