Agkistrodon bilineatus Günther, 1863

Taxonomic Identification

This species, Agkistrodon bilineatus Günther, 1863, consists of heavy-bodied snakes that share the same general body structure as copperheads.

Adult Size & Head Morphology

Adults average around 60 cm (24 in) in length, with a broad, triangular head, small eyes, and vertical pupils.

General Body Coloration

Overall coloration is variable, but most individuals are brown or black with darker brown or black banding, sometimes marked with white or cream-colored accents.

Related Species Patterning

A closely related form, A. taylori, is known for more elaborate patterning, often with distinct tan-colored banding that sometimes includes orange or yellow accents that can appear almost gold in color.

Head Markings

This species has characteristic yellow and/or white lines on the head: a vertical line on the rostral and mental scales, a fine line on the canthus that continues above and beyond the eye to the neck, and a broader line on the upper lip running from the anterior nasal scale to the last labial scale.

Juvenile Appearance

Juveniles are almost always distinctly banded, with bright green or yellow tail tips that they use to lure prey.

Ontogenetic Color Change

As individuals age, their pattern and coloration fade and darken.

Geographic Distribution

This species is found across Mexico and Central America, along the Pacific side from southern Sonora in Mexico, south through Guatemala, El Salvador, and Honduras.

Type Locality

The species’ type locality is given as "Pacific coast of Guatemala."

Breeding Period

Breeding takes place in the spring.

Reproduction

Like most other viper species, cantils are ovoviviparous, and give birth to between 5 and 20 young at a time.