Characterized by an extremely slender and elongated body with a distinct head that stands out from the neck, featuring a rounded snout and remarkably large eyes with round pupils. The dorsal coloration is a uniform, vibrant bright green, which can occasionally exhibit yellowish or olive undertones, whereas the ventral surface displays a contrasting creamy white, pale yellow, or light greenish hue without dark spots. The dorsal scales are smooth or weakly keeled, typically arranged in 19 rows at midbody. Adult specimens usually attain total lengths ranging from 31 to 43 inches (80 to 110 centimeters), although exceptional individuals can reach up to 55 inches (140 centimeters), with females being notably larger and heavier than males. It possesses an opisthoglyphous dentition, with enlarged grooved fangs located at the rear of the upper jaw connected to Duvernoy’s glands.
Geographical distribution: Widely distributed throughout the central and southern regions of South America. Its geographic range encompasses vast areas of Brazil (particularly within the Cerrado, Atlantic Forest, and southern Pampa biomes), the entirety of Uruguay, most of Paraguay, eastern Bolivia, and northern to central Argentina, reaching its southernmost limit in the provinces of La Pampa and Buenos Aires.
Habitat: Shows a high degree of ecological plasticity, primarily inhabiting open and transitional environments. It is frequently observed in wet grasslands, savannas, forest edges, wetlands, xerophytic scrublands, agricultural fields, and disturbed peri-urban areas. Its semi-arboreal nature allows it to effectively utilize both the terrestrial floor and the low shrubby vegetation, adapting well to human-modified landscapes provided there is adequate cover.
Feeding: Exhibits a highly generalist and opportunistic carnivorous diet that changes with age and seasonal prey abundance. It actively preys upon amphibians (especially tree frogs and small toads), lizards, small mammals such as rodents, nestling birds and their eggs, and occasionally large invertebrates during its juvenile stages. It utilizes a combination of visual pursuit, mild constriction, and the injection of toxic secretions from Duvernoy’s gland to quickly immobilize and digest its prey.
Behavior: Strictly diurnal and remarkably agile, moving with great speed both on the ground and while climbing through the branches of low bushes and trees. During the morning hours, it is often seen basking on branches to thermoregulate. It is generally timid, preferring to flee rapidly when approached; however, if cornered, it displays defensive behaviors such as neck inflation, false strikes, and potential defensive bites, which can inoculate mild venom causing localized swelling and pain in humans but posing no severe medical danger.
Reproduction: Classified as an oviparous reptile with a seasonal reproductive cycle. Mating occurs primarily during the austral spring, triggered by rising temperatures and the onset of the rainy season. Gravid females deposit clutches of 5 to 18 elongated, flexible-shelled eggs in sheltered microhabitats with high humidity, such as decaying leaf litter, rotten logs, or beneath flat rocks. The incubation period lasts between 60 and 90 days, after which completely independent hatchlings emerge, measuring around 7 to 9.5 inches (18 to 24 centimeters) in length.
Conservation status: Currently classified as Least Concern (LC) in most regional assessments due to its extensive distribution, stable population trends, and adaptability to moderate habitat alteration. Nevertheless, local populations face localized declines resulting from habitat fragmentation, conversion of native grasslands for intensive agriculture, and direct human persecution stemming from deeply ingrained fears of snakes.
Compilation and publication: EcoRegistros – 01/08/2026