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The Twin-barred Tree Snake (Chrysopelea pelias) is one of five species of tropical lowland tree snakes of southern and southeast Asia that together comprise the genus Chrysopelea, the "flying snakes". Chrysopelea snakes are on the order of 0.6–1.2 m in length, with a body mass ranging from tens to a few hundred grams. (Socha 2011) Chrysopelea pelias inhabits lowland forests habitats and has been recorded in southern Thailand, Peninsular Malaysia and offshore islands, Singapore, Sumatra, Java, Borneo and adjacent islands at altitudes up to 600 m. It is diurnal and displays terrestrial and arboreal behavior. It is oviparous and feeds on small vertebrates such as lizards and frogs. Maximum total length is recorded at 74 cm, although mature adults are usually less than 65 cm. (Ismail et al. 2010 and references therein)
Chrysopelea snakes are best known for their remarkable gliding abilities. At least four of the five species are known to be capable of gliding (according to Socha , gliding has been studied under experimental conditions in C. ornata, C. paradisi, and C. pelias; C. rhodopleuron, which occurs in Sulawesi and the Moluccas, has also been observed to glide, but the gliding abilities of the Sri Lankan endemic C. taprobanica are unknown).
Chrysopelea “flying” snakes are the only limbless animals that glide through air. These snakes can actively launch by jumping, maintain a stable glide path, maneuver, and safely land without injury. As the snake becomes airborne, the body flattens sequentially from head to vent, forming a cross-sectional shape that is roughly triangular, with a flat surface and lateral ‘‘lips’’ that protrude ventrally on each side of the body; these may diminish toward the vent. A glide trajectory is initiated with the snake falling at a steep angle. As the snake rotates in the pitch axis, it forms a wide ‘‘S’’ shape and begins undulating in a complex three dimensional pattern, with the body angled upward relative to the glide path. The head moves side-to-side, sending traveling waves posteriorly toward the tail, while the body (most prominently, the posterior end) oscillates in the vertical axis. These active movements while gliding are substantially different and more dynamic than those used by any other animal glider. As the snake gains forward speed, the glide path becomes less steep, reaching minimally recorded glide angles of 138. In general, smaller snakes appear to be more proficient gliders. Morphologically, Chrysopelea appear to be typical snakes, with no special appendages, skin flaps, or other features such as are used by other flying animals. Instead, the snake undergoes aerial locomotion by using its entire body as a flattened, moving wing, constantly reconfiguring it throughout flight.
(Socha 2011 and references therein)
Ismail et al. (2010) report on the medical consequences of a snakebite believed to be attributable to C. pelias (symptoms were serious but not life threatening). Snakebites by rear-fanged species, such as Chrysopelea snakes, are relatively uncommon so the consequences of bites by rear-fanged species are generally less well known. However, some rear-fanged species can be dangerous to humans, so reports of bites by rear-fanged species can be of particular interest.