Philodryas aestiva

Philodryas aestiva is a species of snake of the family Colubridae. It is commonly known as the Brazilian green racer and the common green racer.
The genus Philodryas, Philo which is Greek means "loving" or "fond of" and dryas also Greek means "tree" or "oak," also used for "tree nymph" in mythology. Philodryas can be interpreted as "tree-loving" or "fond of trees"- referring to its semi-arboreal habits. Many species in this genus are known for being agile climbers. The species name aestiva comes from the Latin aestīvus and means "of the summer" or "summery" which could refer to its active season or its coloration that blends well in sunny or leafy environments. If you put the name together, Philodryas aestiva roughly means "summer-loving tree snake" or "summery tree-dweller", hinting at its habitat and activity patterns.
Philodryas aestiva inhabits a wide range of environments in South America. They're especially found in Brazil, Argentia, Paraguay, Bolivia, and Uruguay. The animal prefers open forests and savannahs (e.g., the Cerrado biome in Brazil), dry forests, scrublands, grasslands and the edges of agricultural areas. They're sometimes found in semi-urban or rural areas.
Philodryas aestiva, recognized for its vibrant green coloration and remarkable speed—reaching up to 15 miles per hour—is a highly agile snake, hence the name "green racer." Its slender body and large eyes contribute not only to its swift movement but also to its climbing ability.
It is diurnal, actively foraging during the day using its keen vision and speed. Although primarily terrestrial, P. aestiva is also semi-arboreal, readily climbing low vegetation and shrubs but typically remaining close to the ground. It is territorial and solitary, generally encountered alone outside the breeding season.
When threatened, it may flatten its body and inflate its neck to appear larger, hiss loudly, and strike defensively. However, it generally prefers to flee and is not aggressive toward humans unless provoked or handled.
Philodryas, including P. aestiva, are opisthoglyphous (rear-fanged) snakes and can deliver venomous bites. P. aestiva is an opportunistic carnivore with a broad and adaptable diet. It preys on small mammals (rodents), birds and bird eggs, lizards, frogs, amphibians, other snakes and occasionally insects or invertebrates during its juvenile stage. P. aestiva uses both active foraging and ambush tactics, taking advantage of its speed and agility. P. aestiva produces mild venom from its Duvernoy’s glands (gland found in some groups of colubrid snakes, it is distinguished from the venom gland of viperids or elapids) which helps subdue small prey. While not dangerous to humans, the venom contains compounds such as snake venom metalloproteinases that contribute to prey immobilization and digestion through hemorrhagic and inflammatory effects.
P. aestiva is an oviparous (egg-laying) species. Breeding generally occurs in the warmer months, from September to December in the southern hemisphere, triggered by temperature and photoperiod changes. Females lay clutches of 4 to 14 eggs, depending on their size, age, and environmental conditions.
Eggs are deposited in moist, sheltered places, such as beneath leaf litter or inside burrows. The incubation period lasts 40–60 days, influenced by temperature and humidity. Hatchlings are fully independent and begin feeding shortly after emergence.
Notably, females can exhibit sperm storage, allowing fertilization to occur long after mating—an adaptation that helps synchronize reproduction with favorable conditions for the juveniles.
P. aestiva hatchlings typically measure around 25–30 cm (9.8–11.8 in) at birth. Adults reach lengths of 1.2–1.8 m (3.9–5.9 ft), though some individuals may exceed this in the wild. Their growth rate depends on factors such as food availability, temperature, and overall habitat quality. Juveniles grow relatively fast during their first year, with growth slowing as they approach maturity.
In the wild, the estimated lifespan of P. aestiva is around 8–10 years. In captivity they may live slightly longer, sometimes up to 12 years or more. However, factors like predation and environmental stressors can reduce their lifespan in natural habitats.
While Philodryas aestiva do not exhibit extreme visual differences between sexes, there are subtle distinctions. Males are generally smaller and more slender, while females tend to be larger and more robust, especially during the breeding season. Males have longer tails relative to their body length, whereas females have shorter tails. Additionally, the cloacal distance (from vent to tail tip) is greater in males and shorter in females. These features are most noticeable when comparing individuals side by side. In the field, determining sex typically requires gentle probing or visual inspection by trained herpetologists.
*Species Philodryas aestiva at The Reptile Database