Black-tailed Horned Pitviper

A small to medium-sized pit viper typically measuring 16–24 inches (41–61 cm) in total length. Body is moderately robust with a broad, distinctly flattened head set off from the neck. A characteristic pair of horn-like modified scales projects upward from the head between and slightly anterior to the eyes, giving the species its common name. Dorsal coloration is highly variable, ranging from gray, tan, olive, or yellowish-brown to reddish-brown or nearly black, usually overlaid with a series of darker brown to blackish crossbands or blotches that may be more or less distinct depending on individual and population. The distinctive tail is uniformly dark brown to black, lacking banding or patterning, which provides a reliable diagnostic feature. Scales are strongly keeled, contributing to a somewhat rough texture. Vertical pupils and prominent loreal pits are present. Ventral surface is pale tan to cream, often spotted or mottled with darker pigmentation. Primarily inhabits montane cloud forests, pine-oak forests, and forested ravines at moderate to high elevations in central Mexico, typically associated with vegetation near the ground. Diet consists primarily of small vertebrates including lizards, small snakes, and occasionally small mammals and amphibians, subdued via envenomation.