Black-tailed Cribo
Drymarchon melanurus • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Colubrinae, Genus: Drymarchon, Species: melanurus
Distributed from the extreme Rio Grande Valley in Texas, USA, southward through the Gulf Coast and Pacific lowlands of Mexico, across Central America, and into northwestern South America (Colombia, Ecuador, Venezuela).
Look up Black-tailed Cribo in the Snake Encyclopedia →Venomous Status
Non-venomous; lacks fangs or a specialized delivery system for medically significant venom.
Danger Level
Low Risk; harmless to humans and generally avoids confrontation. Large adults may bite defensively if handled, which can cause significant mechanical trauma due to their powerful jaws, but they pose no toxicological threat.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Colubrinae, Genus: Drymarchon, Species: melanurus
Conservation
IUCN Least Concern. Threats include habitat destruction, road mortality, and persecution by humans who mistake them for venomous species.
Physical Description
A large, robust-bodied snake with smooth, glossy scales. Generally light brown or olive-tan on the anterior half of the body, transitioning to solid black toward the tail. Diagnostic features include black vertical markings on the labial (lip) scales and a dark 'smudge' or diagonal line behind the eye. Scales are large and iridescent.
Size & Dimensions
The specimen in the image appears to be an adult approximately 1.5 to 2 meters long. Species average is 1.8 to 2.4 meters (6-8 feet), with maximum lengths reaching nearly 3 meters.
Habitat
Inhabits a wide variety of environments including tropical rainforests, seasonally dry forests, coastal scrublands, and agricultural areas. It is found from sea level up to approximately 1,900 meters and is primarily terrestrial but comfortable in water.
Behavior & Temperament
Diurnal active forager. Known for being highly active and alert. When threatened, it may inflate its neck vertically (puffing) to look larger, hiss loudly, and vibrate its tail, though it typically prefers to flee.
Diet & Feeding
An opportunistic generalist predator. It feeds on rodents, birds, lizards, frogs, and other snakes (including venomous species like pit vipers). They do not constrict; they seize prey and overpower it with strong jaws, often swallowing it alive.
Reproduction
Oviparous (egg-laying). Females lay clutches of 4 to 15 large eggs, usually in the late winter or early spring. Large hatchlings emerge after an incubation period of about 60-90 days.
Venom Profile
Non-venomous - no medically significant venom.
Look-alikes
Commonly confused with the Indigo Snake (Drymarchon couperi), which is typically solid blue-black throughout. Also confused with the Brown Racer (Coluber constrictor) or tropical rat snakes, but the heavy body and black tail are diagnostic.
Conservation Status
IUCN Least Concern. Threats include habitat destruction, road mortality, and persecution by humans who mistake them for venomous species.
Cultural Significance
Ecologically vital as an apex predator that controls rodent populations and keeps other snake populations in check. In some regions, they are respected by farmers for their ability to eat venomous 'Fer-de-Lance' vipers.
Notable Features
Remarkable for their immunity or high resistance to the venom of local pit vipers. They have one of the most powerful bites among non-constricting colubrids and display high intelligence and curiosity compared to many other snakes.