Patagonia Green Racer

Fascinating facts about the Patagonia Green Racer

• At up to 150 cm long, the Patagonia green racer is found in the Patagonian steppe where it hunts.
• Females are longer and bulkier than males, while males have a proportionally longer tail.
• Juveniles stick to ectothermic meals like lizards, but adults switch to endothermic animals such as rodents, essentially growing a hotter-blooded diet as they age. The shift highlights a dramatic change in hunting strategy within a single lifetime.
• Its venom is a protein cocktail that is 90 % protein, packed with metalloproteinases that cause swelling, bleeding, pain and tissue death. With an LD50 of 58.58 µg in mice, the toxin is almost as potent as that of the notorious Bothrops jararacussu, yet the rear-fanged delivery makes envenomation harder, reminding us that danger isn’t just about poison strength.
• Despite being called a “Patagonia” racer, this snake’s range stretches far beyond the southern plains into Brazil’s Cerrado, the Chaco, and even open patches of the Atlantic forest, proving that common names can hide a species’ true ecological versatility.

At a glance

About the Patagonia Green Racer

The Patagonia green racer, Philodryas patagoniensis, is a medium-sized, cylindrical colubrid that can reach up to 150 cm (59 in) in total length. Its smooth dorsal scales bear unique apical scores, and a rounded snout frames a medium-sized eye with a round pupil. Brownish hues cloak the snake, granting it excellent camouflage across the open landscapes it inhabits, from the windswept Patagonian steppe and the savanna-like Cerrado to the dry Chaco, the thorny Caatinga, and the sun-lit clearings of the Atlantic forest. Though fundamentally terrestrial, it becomes arboreal when hunting, moving with swift, diurnal confidence among low branches and ground litter. A versatile predator, P. patagoniensis feeds on a surprising range of prey: juveniles target ectothermic animals, while adults turn to endotherms, and even conspecifics fall victim to its opportunistic appetite. Its rear-fanged, opisthoglyphous dentition delivers toxic saliva rich in metalloproteinases, neurotoxic and myotoxic compounds that echo the potency of Bothrops species, yet the snake often struggles to inject venom effectively. Sexual dimorphism is pronounced; females grow longer, bulkier bodies and mature at about two years, whereas males develop longer tails and reach maturity in a single year. Seasonal reproduction peaks between July and October, when females undergo vitellogenesis, ensuring the next generation of these striking, adaptable racers.

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