Green snakes, with their striking coloration, blend seamlessly into diverse environments, from lush forests to suburban gardens. This article explores the natural reasons behind their green appearance, introduces several common green snake species, provides guidance on identifying them, and offers advice for safe encounters.
Why Snakes Appear Green
The vibrant green coloration observed in many snake species serves a primary function as camouflage within their leafy habitats. This hue results from a complex interplay of pigments and structural elements within their skin. Specialized cells called chromatophores contain various pigments that absorb and reflect light. For instance, yellow pigments, such as pteridines and carotenoids, are often present.
Beyond pigments, structural colors contribute to the green appearance through light scattering and interference. Iridophores, another type of chromatophore, contain light-reflecting platelets composed of crystalline purines. When these structural components interact with incident light, they can reflect specific wavelengths, such as green and yellow. The combination of yellow pigments with the blue light reflected by iridophores creates the perception of green. This evolutionary adaptation allows these snakes to remain hidden among foliage, trees, and grass.
Meet Some Green Snakes
The Rough Green Snake, Opheodrys aestivus, is a non-venomous colubrid native to North America, ranging across the southeastern United States and into northeastern Mexico. It is a slender snake, typically growing up to 1.16 meters (45 inches) in total length, with keeled dorsal scales that give it a slightly rough texture. Rough Green Snakes are highly arboreal, often found climbing in low vegetation near water, and primarily consume insects and other arthropods.
The Green Tree Python, Morelia viridis, comes from the tropical rainforests of New Guinea, parts of Indonesia, and northern Australia. This non-venomous constrictor can reach an average length of 1.5 meters (5 feet), with some individuals exceeding 2 meters (6.6 feet), and has a distinctive prehensile tail used for gripping branches. Its body is bright green with a visible spine, and adults may have a yellowish belly or white markings along their back. Green Tree Pythons are nocturnal and arboreal, hunting small mammals and reptiles.
The Ornate Flying Snake, Chrysopelea ornata, is a mildly venomous, rear-fanged colubrid found across South and Southeast Asia. This slender species, typically reaching about 1.2 meters (4 feet) in length, is known for its ability to glide between trees by flattening its body. Its coloration is usually green with black cross-hatching and yellow or gold accents, sometimes featuring flower-shaped reddish or orange vertebral spots. Ornate Flying Snakes are diurnal and primarily prey on lizards, frogs, birds, and small mammals; their venom is not considered dangerous to humans.
The Bush Viper, Atheris squamigera, is a highly venomous viper species found in the rainforests of West and Central Africa. This arboreal snake is characterized by a stout body, a broad, flat head distinct from its neck, and heavily keeled, imbricate scales that give it a somewhat bristly appearance. While often green, its coloration can be quite variable, including yellow, blue, or even red. Bush Vipers are nocturnal ambush predators that feed on small mammals, birds, and lizards, and their hemotoxic venom can cause severe complications in humans.
Identifying Green Snakes
Distinguishing between different green snake species involves observing several physical and behavioral characteristics beyond their color alone. Body shape and size can provide initial clues; some species are long and slender, like the Rough Green Snake, while others are stout-bodied, such as the Bush Viper. Head shape is another indicator; some snakes have heads that are distinctly wider than their necks, whereas others have heads that blend more continuously with their bodies.
Pupil shape can also offer insights, with some snakes possessing round pupils and others having elliptical or cat-like pupils. The texture of their scales, whether smooth or keeled (ridged), provides further differentiation, as seen with the keeled scales of the Rough Green Snake and Bush Viper versus the smoother scales of some other species. Behavioral cues are also helpful; observing whether a snake is primarily arboreal (tree-dwelling) or terrestrial (ground-dwelling), or if it exhibits specific defensive displays, can aid in identification. Accurate identification often relies on combining these multiple characteristics.
Encountering Green Snakes Safely
Encountering a snake in its natural habitat can be a fascinating experience, and maintaining a respectful distance is always advised. If you see a green snake, observe it from afar and avoid any attempts to approach, handle, or provoke it. Most snakes are not aggressive and will only strike if they feel directly threatened or cornered. Sudden movements can startle a snake, prompting a defensive reaction.
If a snake is in an undesirable location, such as a yard or home, the safest approach is to leave it alone if it is moving away. In situations where the snake poses a perceived risk or is in an enclosed space, it is best to contact local animal control or wildlife experts for assistance. While many green snakes are harmless, misidentification can occur, so caution is always a sensible approach to ensure the safety of both humans and the snake.