Reptiles
Flying Snake
Chrysopelea · also called flying snakes, gliding snakes
A flying snake does not fly, but it does the next best thing. It climbs to a high branch, hangs its front half out in a J, then flings itself into the air, sucks in its belly, and flattens its whole body into a wide ribbon that works as a wing. As it falls forward it wriggles as if swimming, and that aerial slithering is what keeps the glide steady enough to land on a chosen tree up to 100 metres away.
Overview
Flying snakes are the genus Chrysopelea, five slender, day-active tree snakes of the rainforests, mangroves, and gardens of South and Southeast Asia, from Sri Lanka to the Philippines. They are rear-fanged colubrids with a mild venom, hunting geckos, skinks, frogs, bats, and birds among the branches. They spend almost their whole lives in the canopy.
Turning the body into a wing
Launching, the snake pulls in its belly and flares its ribs, changing its round cross-section into a flattened, concave aerofoil about twice its resting width, and holds the body in a loose horizontal S. This generates lift and slows the fall — a glide of 10 m from a low start and up to 100 m from a tall tree, with enough control to steer and pick a landing.
Swimming through the air
Throughout the glide the snake sends travelling waves down its body, head to tail — the same undulation it uses to crawl. Wind-tunnel studies show this aerial slithering stabilises the glide and stops the snake from tumbling, so it is doing real aerodynamic work, not just twitching.
Status
All five species are Least Concern — widespread, adaptable to plantations and wooded gardens, and locally common. They are collected in modest numbers for the pet trade (where they do poorly) and killed by people who fear snakes, but as canopy animals they mainly need connected tree cover, which heavy deforestation removes.
Flying Snake: common questions
Can flying snakes actually fly?
No. They cannot flap, they cannot gain height, and they cannot sustain themselves in the air, so what they do is gliding, not flying. A flying snake climbs to a high point, hangs the front of its body off the branch in a J-shape, and then springs up and out, and from that moment it is falling, but by flattening its body and adopting the right posture it converts a lot of that fall into forward travel, so it follows a shallow, curving path to a landing point that can be many metres away and much lower down. It is one of the more effective gliders among vertebrates despite having no wings, membranes, or flaps of any kind.
How does a snake with no wings glide?
By reshaping its own body into an aerofoil and controlling its posture. As it leaves the branch, the flying snake pulls in its belly and splays its ribs sideways, which turns its round body into a wide, flattened, gently concave ribbon roughly twice its normal width, a shape that generates lift as air flows over it. It holds itself in a loose S from above and keeps the body angled slightly nose-up, and it sends continuous travelling waves down its length, the same wriggling motion it uses to crawl. Aerodynamic studies show this undulation is not incidental; it keeps the glide stable and prevents the snake from pitching or rolling out of control. The snake can also make small adjustments to change direction and pick a landing spot.
Are flying snakes dangerous?
Not to people. They are rear-fanged snakes with a mild venom that works on lizards and frogs but has little effect on humans, and they would have to chew on a person for a while to deliver even that. They are also shy, fast, and far more interested in escaping than confronting anything large. A bite, which is rare, produces minor swelling and itching at most. The snakes are harmless around gardens and are, if anything, useful, eating geckos and rodents. The alarming part is purely the sight of a snake apparently launching itself out of a tree.
Can you keep a flying snake as a pet?
They are occasionally kept but are a poor choice for most keepers. Flying snakes are nervous, fast, and fully arboreal, so they need a tall, densely planted enclosure with plenty of climbing branches and secure ventilation, high humidity, and warmth, and they will stress and refuse food in a small or bare tank. They are also difficult to feed, since most individuals will only take live lizards, especially geckos, which is expensive and impractical to sustain, and they do not tolerate handling well. Wild-caught animals, which is most of what is available, often arrive dehydrated and parasitised. For nearly everyone they are best appreciated in videos rather than in a vivarium.