Golden Liophis

Characterized by a robust and cylindrical body, this medium-to-large-sized reptile typically measures between 90 and 130 centimeters in total length, though exceptional adult specimens may exceed 150 centimeters. The head is moderately distinct from the neck, featuring medium-sized eyes with circular pupils. Its dorsal coloration is generally olive-green, grayish-green, or brownish, occasionally adorned with faint dark transverse bands or spots that are more prominent in juveniles than in adults. Its most diagnostic feature is the ventral surface, which displays a striking bright golden-yellow coloration on the mid and posterior sections of the body, interspersed with irregular dark square markings resembling a checkerboard pattern. The dorsal scales are completely smooth, arranged in 19 rows at midbody.

Geographical distribution: This species is native to the temperate and subtropical regions of southern South America. Its geographic range encompasses southern Brazil (specifically the state of Rio Grande do Sul), the entirety of Uruguay, eastern Paraguay, and northeastern Argentina, where it is widely distributed across the provinces of Misiones, Corrientes, Entre Ríos, Santa Fe, Chaco, Formosa, and Buenos Aires, reaching its southernmost limit along the wetlands of the Río de la Plata estuary.

Habitat: Primarily associated with freshwater ecosystems and humid transitional zones, this semi-aquatic snake occupies a variety of wetlands. It is frequently encountered in marshes, swamps, permanent and temporary lagoons, flooded grasslands, and slow-moving riverbanks. It has also adapted successfully to human-modified landscapes, commonly inhabiting flooded rice fields and drainage ditches, where it finds refuge within dense mats of floating and emergent aquatic vegetation.

Feeding: This carnivorous predator exhibits a highly specialized diet focused primarily on aquatic and semi-aquatic prey. Its main food sources are amphibians, particularly adult frogs and toads of the genera Leptodactylus and Rhinella, as well as their tadpoles in shallow waters. It also acts as an opportunistic hunter, preying upon small fish trapped in ephemeral pools, and occasionally consuming small lizards, frogs´ eggs, or newborn rodents found near water bodies.

Behavior: Exhibiting mainly diurnal and crepuscular activity patterns, this snake is most active during the warmest hours of the day. It is frequently seen basking on floating vegetation or muddy banks to thermoregulate. It is an exceptional swimmer, navigating aquatic environments with ease and speed. When threatened, its primary defense is to escape into deep water; however, if cornered, it performs an impressive defensive display by flattening its body and head dorsoventrally to mimic venomous pit vipers, and it may discharge a foul-smelling musk from its cloacal glands to deter predators.

Reproduction: This is an oviparous species whose reproductive cycle is closely tied to the warm and rainy seasons of late spring and summer. Mating occurs after the winter dormancy period. Females, which are typically larger than males, lay clutches containing between 8 and 22 leathery eggs. These clutches are carefully deposited in warm, humid microhabitats, such as rotting logs, subterranean cavities, or decaying leaf litter, which provide stable incubation conditions. The incubation period lasts between 60 and 75 days, after which the independent neonates emerge.

Conservation status: Classified as a species of Least Concern (LC) on both global and national red lists due to its wide distribution and relatively stable populations. Nevertheless, local populations face severe threats from habitat destruction and fragmentation, particularly the draining of wetlands for agricultural development, the intensive use of pesticides in rice cultivation, and direct mortality caused by humans who mistakenly identify it as a venomous snake.