Geographic range: Nearctic, Neotropical: T. scaliger is native to Central Mexican Plateau. It is found in provinces of Guanajuato, Jalisco, Mexico, Michoacan, Puebla, San Luis Potosi, Tlaxcala and Federal District.

Physical characteristics: A medium sized snake (40 to 50 cm). Females are bigger than males. Body color ranges from clove brown to gray. Distinctive are paired brownish spots distributed on both sides of light gray central vertebral line. Dorsal scales of the body are keeled. The head is of the same color as the dorsal part of the body, ventral side is lighter - cream color.

Food habits: Principal food items are amphibians and reptiles, especially members of sympatric species of Pseudoeurycea, Hyla and Sceloporus.

Reproduction: There is very little evidence on this subject. The species is considered viviparous. Females collected during the moth of June held around 7 embryos (110 mm long) ready to be born.

Behavior: T. scaliger is a terrestrial diurnal species that prefers habitats with scattered rocks, fallen tree trunks, fallen leaves and other objects that can serve as shelters. Frequently occupies empty burrows.

Habitat: Inhabits principally pine and pine - oak forests in higher altitudes (2700 - 3500 m).

Biomes: temperate forest