|Ornate flying snake, Chrysopelia ornata|
Chrysopelea, more commonly known as the flying snake or gliding snake is a genus that belongs to the family Colubridae. Flying snakes are mildly venomous, though the venom is dangerous only to their small prey. Their range is in Southeast Asia (the mainland (Vietnam, Cambodia, and Laos), Greater and Lesser Sundas, Maluku, and the Philippines), southernmost China, India, and Sri Lanka.
Chrysopelea is also known by its common name "flying snake". It climbs using ridge scales along its belly, pushing against rough bark surface of tree trunks, allowing it to move vertically up a tree. Upon reaching the end of a branch, the snake continues moving until its tail dangles from the end of the branch. It then makes a J-shape bend, leans forward to select the level of inclination it wishes to use to control its glide path, as well as selecting a desired landing area. Once it decides on a destination, it propels itself by thrusting its body up and away from the tree, sucking in its abdomen and flaring out its ribs to turn its body into a "pseudo concave wing", all the while making a continual serpentine motion of lateral undulation parallel to the ground to stabilise its direction in midair in order to land safely.
The combination of forming a C-shape, flattening its abdomen and making a motion of lateral undulation in the air makes it possible for the snake to glide in the air, where it also manages to save energy compared to travel on the ground and dodge earth-bound predators. The concave wing that the snake creates in flattening itself, flattens its body to up to twice its width from the back of the head to the anal vent, which is close to the end of the snake's tail, causes the cross section of the snake's body to resemble the cross section of a frisbee or flying disc. When a flying disc spins in the air, the designed cross sectional concavity causes increased air pressure under the centre of the disc, causing lift for the disc to fly. The snake continuously moves in lateral undulation to create the same effect of increased air pressure underneath its arched body to glide. Flying snakes are able to glide better than flying squirrels and other gliding animals, despite the lack of limbs, wings, or any other wing-like projections, gliding through the forest and jungle it inhabits with the distance being as great as 100 m. Their destination is mostly predicted by ballistics; however, they can exercise some in-flight attitude control by "slithering" in the air.
Their ability to glide has been an object of interest for physicists and the United States Department of Defense in recent years, and studies continue to be made on what other, more subtle, factors contribute to their gliding. According to recent research conducted by the University of Chicago, scientists discovered a negative correlation between size and gliding ability, in which smaller flying snakes were able to glide longer distances horizontally.
According to research performed by Professor Jake Socha at Virginia Tech, these snakes can change the shape of their body in order to produce aerodynamic forces so they can glide in the air. Scientists are hopeful that this research will lead to the design of robots that can glide in the air from one place to another.
The species is considered mildly venomous, with a few confirmed cases of medically significant envenomation. Chrysopelea species are not included in lists of snakes considered venomous to people.
There are five recognized species of flying snake, found from western India to the Indonesian archipelago. Knowledge of their behavior in the wild is limited, but they are thought to be highly arboreal, rarely descending from the canopy. The smallest species reach about 2 feet (0.6 m) in length and the largest grow to 4 feet (1.2 m).
Their diets are variable depending on their range, but they are known to eat rodents, lizards, frogs, birds, and bats. They are mildly venomous snakes, but their tiny, fixed rear fangs make them harmless to humans.
Golden tree snake or ornate flying snake, Chrysopelea ornata (Shaw, 1802): This is the largest species of flying snake, reaching up to four feet in length. Though it is called the golden tree snake, there are other colour variations; for example, some phases tend to lean towards lime green in colour rather than pure yellow, while in India, it has orange to red markings and small black bars on the dorsum, almost as rich in colouration as the paradise tree snake. Due to their size, their gliding ability is considered weak.
Paradise tree snake, Chrysopelea paradisi (Boie & Boie, 1827): This flying snake species reaches up to three feet in length and is popular in the European pet trade. Their bodies are black, but covered in rich green scales. Clusters of red, orange, and yellow-coloured scales in the shape of flower petals line the dorsal area from the base of the neck to the tail. This is the most well known colouration, but some specimens may exhibit fully green colouration without any bright dorsal markings. Their gliding ability is considered one of the best among the flying snakes.
Twin-barred tree snake or banded flying snake, Chrysopelea pelias (Linnaeus, 1758): This is the smallest flying snake species, reaching up to two feet in length. Its base colour is black or dark grey, and the entire body is covered with thick red and thin yellow with black bands. They also have cream-coloured ventrolateral lines, while the ventrals are pale green. While it is tiny, it is undoubtedly one of the rarest flying snake species within its range. Although it is able to move horizontally through the air when gliding, it does not glide as well as C. paradisi.
Lesser-studied species are:
- Moluccan flying snake, Chrysopelea rhodopleuron (Boie, 1827): From Ambon and Sulawesi in Indonesia.
- Sri Lankan flying snake, Chrysopelea taprobanica (Smith, 1943): From Sri Lanka.
- "Researchers reveal secrets of snake flight". 2005-05-12. Retrieved 2007-11-27.
- "University of Chicago researchers reveal secrets of snake flight". The University of Chicago Medical Center. May 13, 2005. Retrieved 14 July 2009.
- Ferner, J.W.; Brown, R.W.; Sison, R.V.; Kennedy, R.S. (2000). "The Amphibians and Reptiles of Panay Island, Philippines" (PDF). Asiatic Herpetological Research. 9: 1–37. Archived from the original (PDF) on 2011-07-21. Retrieved 2009-07-14.
- Socha, J. (1999–2005). "Approximate distribution of Chrysopelea". flyingsnake.org. Retrieved 14 July 2009.
- Pawar, S. and Birand, A. "A survey of amphibians, reptiles, and birds in northeast India Archived July 6, 2010, at the Wayback Machine" CERC Technical Report No.6 . Centre for Ecological Research and Conservation, Mysore. 2001. Accessed 2009-07-14.
- De Rooij, N. (1915). "The reptiles of the Indo-Australian archipelago" Leiden: E.J. Brill. Accessed 2009-07-14.
- Dudley, R; Byrnes, G.; Yanoviak, S.P.; Borrell, B.; Brown, R.M.; McGuire, J.A. (2007). "Gliding and the Functional Origins of Flight: Biomechanical Novelty or Necessity?" (PDF). Annual Review of Ecology, Evolution, and Systematics. 38: 179–201. doi:10.1146/annurev.ecolsys.37.091305.110014. Archived from the original (PDF) on 2011-01-12. Retrieved 2009-07-14.
- Garland, T Jr.; Losos, J.B. (1994). "10. Ecological morphology of locomotor performance in squamate reptiles" (PDF). Ecological morphology: integrative organismal biology. Chicago, IL: University of Chicago Press. pp. 240–302. Retrieved 2009-07-14.
- Jayne, B.C. (December 1986). "Kinematics of Terrestrial Snake Locomotion" (PDF). Copeia. 1986 (4): 915–927. doi:10.2307/1445288. JSTOR 1445288. Archived from the original (PDF) on October 30, 2006. Retrieved 2009-07-15.
- Socha, John J. (August 2002). "Gliding flight in the paradise tree snake". Nature. 418 (6898): 603–604. doi:10.1038/418603a. ISSN 1476-4687.
- Wei, C. (May 2005). "Inside JEB - Snakes take flight". The Journal of Experimental Biology. 208 (10): i–ii. doi:10.1242/jeb.01644.
- Hummel, S.A. "Frisbee Flight Simulation and Throw Biomechanics Archived February 2, 2010, at the Wayback Machine." University of Missouri, Rolla Ph.D. Thesis. 1997. Accessed 2009-07-14.
- Ernst, C. H.; Zug, G. R. (1996). Snakes in Question: The Smithsonian Answer Book. Smithsonian Institution Press. pp. 14–15.
- Kaufman, Marc (22 November 2010). "DOD tries to uncover secret of flying snakes". The Washington Post. Retrieved 24 November 2010.
- "Flying snake gets lift from UFO cross section". New Scientist: 17. Feb 8, 2014.
- Holden, Daniel; Socha, John J.; Cardwell, Nicholas D.; Vlachos, Pavlos P. (Feb 1, 2014). "Aerodynamics of the flying snake Chrysopelea paradisi: how a bluff body cross-sectional shape contributes to gliding performance". The Journal of Experimental Biology. 217 (3): 382–394. doi:10.1242/jeb.090902. PMID 24477611.
- "The Secret of Flying Snakes is Revealed". BBC Urdu. 30 January 2014. Retrieved 31 January 2014.
- Tan, Toh Leong; Ismail, Ahmad Khaldun; Kong, Kien Woo; Ahmad, Nor Khatijah (April 2012). "Bitten by the "flying" tree snake, Chrysopelea paradisi". The Journal of Emergency Medicine. 42 (4): 420–423. doi:10.1016/j.jemermed.2011.03.038. ISSN 0736-4679. PMID 22154775.
- Silva, Anjana; Weerawansa, Prasanna; Pilapitiya, Senaka; Maduwage, Thilina; Siribaddana, Sisira (September 2013). "First authenticated case of Sri Lankan flying snake (Chrysopelea taprobanica) bite". Wilderness & Environmental Medicine. 24 (3): 273–276. doi:10.1016/j.wem.2013.01.008. ISSN 1545-1534. PMID 23590930.
- "WHO Blood Products and related Biologicals Animal sera Antivenons frames page". apps.who.int. Retrieved 2018-08-26.
- Socha, J. (1999–2005). "Flying Snake Frequently Asked Questions". flyingsnake.org. Retrieved 15 July 2009.
- Socha, J.J. & LaBarbera, M. (March 2005). "Effects of size and behavior on aerial performance of two species of flying snakes (Chrysopelea)". Journal of Experimental Biology. 208 (10): 1835–1847. doi:10.1242/jeb.01580. PMID 15879064.
- Socha, J. (1999–2005). "Chrysopelea pelias aerial images". flyingsnake.org. Archived from the original on 31 July 2009. Retrieved 14 July 2009.