Daboia
Encyclopedia : D : DA : DAB : Daboia
Common names: Russell's viper,Species [Daboia russelii] at the [EMBL Reptile Database] daboia, tic polonga,Ditmars RL. 1937. Reptiles of the World: The Crocodilians, Lizards, Snakes, Turtles and Tortoises of the Eastern and Western Hemispheres. The McMillan Company. 321 pp. tith polonga, kannadi viriyan.Sri Lanka Wildlife Conservation Society - [Checklists of the Snakes of Sri Lanka]
Daboia is a monotypic genus created for of highly venomous viper species, D. russelii, which is found in Asia throughout the Indian subcontinent, much of Southeast Asia, southern China and Taiwan. Within much of its range, this species is easily the most dangerous viperid snake and a major cause of snakebite injury and mortality.Wüster W. 1992. Cobras and other herps in south-east Asia. British Herpetological Society Bulletin 39:19-24.Jena I, Sarangi A. 1993. Snakes of Medical Importance and Snake-bite Treatment. New Delhi: SB Nangia, Ashish Publishing House. 293 pp. It is a member of the big four venomous snakes in India, which are together responsible for nearly all Indian snakebite fatalities.Whitaker Z. 1990. Snakeman. Penguin Books Ltd. 192 pp. ISBN 0140143084. Only two subspecies are currently recognized, including the typical form described here.
Description
D. russelii grows to a maximum length of 166 cm. The average length is about 120 cm on the mainland, although island populations do not attain this size.Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company. ISBN 0-89464-877-2. However, it is more slenderly built than most vipers.Stidworthy J. 1974. Snakes of the world. Grosset & Dunlap Inc. ISBN 0-448-11856-4.
The head is flattened, triangular and distinct from the neck. The snout is blunt, rounded and raised. The nostrils are large, in the middle of a large, single nasal scale. The lower edge of the nasal touches the nasorostral. The supranasal has a strong crescent shape and separates the nasal from the nasorostral anteriorly. The rostral is as broad as it is high. The crown is covered with irregular, strongly fragmented scales. The supraocular scales are narrow, single, and separated by 6-9 scales across the head. The eyes are large, flecked with yellow or gold, and each is surrounded by 10-15 scales. There are 10-12 supralabials, the 4th and 5th of which are significantly larger. The eye is separated from the supralabials by 3-4 rows of suboculars. There are two pairs of chin shields, the front pair of which are notably enlarged. Two to six sets of fangs are present at any one time: the first are active and the rest replacements.
The body is stout, the cross-section of which is rounded to cylindrical. The Dorsal scales are strongly keeled; only the lower row is smooth. Mid-body, the dorsal scales number 27-33. The ventral scales number 153-180. The anal plate is not divided. The tail is short -- about 14% of the total body length -- with the subcaudals numbering 41-68. Subcaudals divided. Ditmars (1937) reported the following dimensions for a "fair sized adult specimen":
| Total length | 4 ft., 1 inch | 124 cm |
| Length of tail | 7 inches | 18 cm |
| Girth | 6 inches | 15 cm |
| Width of head | 2 inches | 5 cm |
| Length of head | 2 inches | 5 cm |
The color pattern consists of a deep yellow, tan or brown ground color, with three series of dark brown spots that run the length of its body. Each of these spots has a black ring around it, the outer border of which is intensified with a rim of white or yellow. The dorsal spots, which usually number 23-30, may grow together, while the side spots may break apart. The head has a pair of distinct dark patches, one on each temple, together with a pinkish, salmon or brownish V or X pattern that forms an apex towards the snout. Behind the eye, there is a dark streak, outlined in white, pink or buff. The venter is white, whitish, yellowish or pinkish, often with an irregular scattering of dark spots.U.S. Navy. 1991. Poisonous Snakes of the World. New York: Dover Books. (Reprint of US Govt. Printing Office, Washington D.C.) 133 pp. ISBN 048626629X.
Geographic range
D. russelii: Pakistan, India, Sri Lanka, Bangladesh, Nepal, Myanmar, Thailand, Cambodia, China (Kwangsi, Kwangtung), Taiwan and Indonesia (Endeh, Flores, east Java, Komodo, Lomblen Islands).Ditmars (1937) also mentions receiving a specimen from the Indonesian island of Sumatra. However, the distribution of D. r. siamensis in the Indonesian archipelago is still being elucidated.Belt P, Warrell DA, Malhotra A, Wüster W, Thorpe RS. 1997. Russell's viper in Indonesia: snakebite and systematics. In R.S. Thorpe, W. Wüster & A. Malhotra (Eds.), Venomous Snakes: Ecology, Evolution and Snakebite. Clarendon Press, Oxford. Symposia of the Zoological Society of London, No. 70:219-234.
Within its range it can be very common in some areas, but scarce in others.
Habitat
Not restricted to any particular habitat, but does tend to avoid dense forests.Gharpurey K. 1962. Snakes of India and Pakistan. Bombay, India: Popular Prakishan. 79pp. Mostly found in open, grassy or bushy areas, Mahendra BC. 1984. Handbook of the snakes of India, Ceylon, Burma, Bangladesh and Pakistan. Annals of Zoology. Agra, India, 22. but may also be found in second growth forests (scrub jungles), on forested plantations and farmland.de Silva A. 1990. Colour Guide to the Snakes of Sri Lanka. Avon (Eng): R&A Publishing Ltd. 88 pp. ISBN 1-872688-00-4. They are most common in plains, coastal lowlands and hills of suitable habitat. Generally not found at altitude, but has been reported as far up as 2300-3000 m. Humid environments, such as marshes, swamps and rain forests, are avoided.Tweedie MWF. 1983. The Snakes of Malaya. Singapore: Singapore National Printers Ltd., 105 pp. ASIN B0007B41IO.This species is often found in highly urbanized areas and settlements in the countryside. As a result, those working outside in these areas are most at risk of being bitten. It should be noted, however, that D. russelii does not associate as closely with human habitation as Naja and Bungarus (cobras and kraits).Whitaker R. 1978. Common Indian Snakes. New Delhi (India): MacMillan. 85 pp.
Behavior
D. russelii is terrestrial and is active primarily as a nocturnal forager. However, during cool weather it will alter its behavior and become more active during the day.
Adults are reported to be persistently slow and sluggish unless pushed beyond a certain limit, after which they becomes fierce and aggressive. Juveniles, on the other hand, are generally more active and will bite with minimal provocation.
When threatened, they will then form a series of S-loops, raise the first third of the body and produce a hiss that is supposedly louder than that of any other snake. When striking from this position, they can exert so much force that even a large individual can lift most of its body off the ground in the process.Daniel JC. 1983. The book of Indian reptiles. Bombay Natural History Society. 119 pp. Among professionals, these snakes have a reputation for being very difficult, and therefore dangerous to handle: they often continue to struggle vigorously even after being grasped firmly behind the head.[[Citing sources citation needed]]
Although this genus does not have the heat-sensitive pit organs common to the Crotalinae, it is one of a number of viperines that are apparently able to react to thermal queues, further supporting the notion that they too possess a heat-sensitive organ.Breidenbach CH. 1990. Thermal cues influence strikes in pitless vipers. Journal of Herpetology, Society for the Study of Reptiles and Amphibians, Vol. 24(4):448-450.
Feeding
Feeds primarily feeds on rodents, especially murid species. However, they will eat just about anything, including rats, mice shrews, squirrels, domestic cats, land crabs, scorpions and other arthropods. Juveniles are crepuscular, feeding on lizards and foraging actively.Vit Z. The Russell's Viper. 1977. Prezgl. Zool. 21:185-8. As they grow and become adults, they begin to specialize in rodents. Indeed, the presence of rodents is the main reason they are attracted to human habitation.Reproduction
D. russelii is ovoviviparous. Mating generally occurs early in the year, although gravid females may be found at any time. The gestation period is more than six months. Young are produced from May to November, but mostly in June and July. It is a prolific breeder. Litters of 20-40 are common. The reported maximum is 65 in a single litter.Wall F. 1906. The breeding of Russell's viper. Journal of the Bombay Natural History Society 16:292-312. At birth, juveniles are 215-260 mm in length. The minimum length for a gravid female is about 100 cm. It seems that sexual maturity is achieved in 2-3 years. In one case, it took a specimen nearly 4.5 hours to produce 11 young.Naulleau G, van den Brule B. 1980. Captive reproduction of Vipera russelli. Herpetological Review. Society for the Study of Amphibians and Reptiles. 11:110-2.Captivity
These snakes do extremely well in captivity, requiring only a water dish and a hide box. Juveniles feed readily on pinky mice, while the adults will take rats, mice and birds. Breeding is not a problem either. They do, however, make quite dangerous captives.Cox M. 1991. The Snakes of Thailand and Their Husbandry. Krieger Publishing Company, Malabar, Florida. 526 pp. ISBN 0894644378.Venom
The amount of venom produced by individuals specimen is considerable. Reported venom yields for adult specimens range from 130-250 mgMinton SA Jr. 1974. Venom Diseases. CC Thomas Publishing, Springfield, Illinois. 386 pp. to 150-250 mg to 21-268 mg. For 13 juveniles with an average length of 79 cm, the average venom yield was 8-79 mg (mean 45 mg).Thwin M, Than T, Hla-Pe U. 1985. Relationship of administered dose to blood venom levels in mice following experimental envenomation by Russell's viper venom. Toxicon (Great Britain) 23:43-52.Thwin M, Mee-Mee K, Kyin M, Than T. 1985. Kinetics of envenomation with Russell's viper venom and of the antivenin use in mice. Toxicon (Great Britain) 26:373-8.The LD50 in mice, which is used as a general indicator of snake venom toxicity, is as follows: 0.08-0.31 μg/g intravenous, 0.40 μg/kg intraperitoneal, 4.75 mg/kg subcutaneous. For most humans a lethal dose is 40-70 mg, which makes D. russelii venom more toxic than that of the other big four species, and even Bothrops and Dendroaspis. In general, the toxicity depends on a combination of five different venom fractions, each of which is less toxic when tested separately.Master RWP, Rao SS. 1961. Identification of enzymes and toxins in venoms of Indian cobra and Russell's viper after starch gel electrophoresis. The Journal of Biological Chemistry 236:1986-90.Dimitrov G, Kankokar R. 1968. Fractionation of Vipera russelli venom by gel filtration I. Venom composition and relative fraction function. Toxicon (Great Britain) 5:213-21. Venom toxicity also varies within populations and over time.
Envenomation symptoms begin with pain at the site of the bite, immediately followed by swelling of the affected extremity.Reid HA. 1968. Symptomatology, pathology, and treatment of land snake bite in India and southeast Asia. In: Bucherl W, Buckley E, Deulofeu V, editors. Venomous Animals and Their Venoms. Vol. 1. New York: Acedemic Press. pp 611-42.Jena I, Sarangi A. 1993. Snakes of Medical Importance and Snake-bite Treatment. New Delhi: SB Nangia, Ashish Publishing House. 293 pp. Bleeding is a common symptom, especially from the gums, and sputum may show signs of blood within 20 minutes post-bite. Sitprija V, Benyajati C, Boonpucknoaviq V. 1974. Further observations of renal insufficiency in snakebite. Nephron 13:396-403. There is a drop in blood pressure and the heart rate falls. Blistering occurs at the site of the bite, developing along the affected limb in severe cases. Necrosis is usually superficial and limited to the muscles near the bite, but may be severe in extreme cases. Vomiting and facial swelling occurs in about one-third of all cases.
According to the U.S. Navy, severe pain may last for 2-4 weeks. Locally, it may persist depending on the level of tissue damage. Often, local swelling peaks within 48-72 hours, involving both the affected limb and the trunk. If swelling up to the trunk occurs within 1-2 hours, massive envenomation is likely. Discoloration may occur throughout the swollen area as red blood cells and plasma leak into muscle tissue.
The venom of this species is widely used in hospital laboratories, specifically in the dilute Russell's viper venom time (dRVVT) test, the results of which can indicate whether a patient suffers from lupus anticoagulant (an autoimmune disorder).
Subspecies
| Subspecies | Authority | Geographic range |
|---|---|---|
| D. r. russelii | Shaw, 1797 | "Across the Indian subcontinent through Pakistan and Bangladesh to Sri Lanka." |
| D. r. siamensis | Smith, 1917 | China (Kwantung), Myanmar, Indonesia (east Java, Komodo, Flores, Lomblen, Endeh), Thailand, Cambodia, Taiwan |
Alternative taxonomies recognize additional subspecies, including:
- D. r. formosensis, found in Taiwan.
- D. r. limitis, found in Indonesia.
- D. r. pulchella, found in Sri Lanka.
- D. r. nordicus, found in northern India.
Taxonomy
The correct spelling of the species, D. russelii has been, and still is, a matter of debate. Shaw & Nodder (1797)Shaw G, Nodder F. 1797. The Naturalist's Miscellany. Volume 8. London: Nodder and Co. 65 pp., in their account of the species Coluber russelii, named it after Dr. Patrick Russell, but apparently misspelled his name, using only one "L" instead of two. Russell (1727-1805) was the author of An Account of Indian Serpents (1796) and A Continuation of an Account of Indian Serpents (1801). McDiarmid (1999) is among those who favor the original misspelled spelling, citing Article 32c (ii) of the International Code of Zoological Nomenclature. Others, such as Zhao and Adler (1993)Zhao EM, Adler K. 1993. Herpetology of China. Society for the Study of Amphibians & Reptiles. 522 pp. ISBN 0916984281. favor russellii.In the future, we may see several other species added to Daboia. Obst (1983)Obst F. 1983. Zur Kenntnis der Schlangengattung Vipera. Zoologische Abhandlungen. Staatliches Museums für Tierkunde in Dresden. 38:229-35. reviewed the genus and suggested that it be extended to include lebetina, palaestinae and xanthina. Groombridge (1980, 1986) united palaestinae and Daboia as a clade based on a number of shared apomorphies, including snout shape and head color pattern. Lenk et al. (2001) found support for this idea based on molecular evidence, suggesting that Daboia not only include palaestinae, but also mauritanica and deserti.
Mimicry
Some herpetologists believe that, because D. russelii is so successful as a species and has such a fearful reputation within its natural environment, another snake has even come to mimic its appearance. Superficially, the rough-scaled sand boa, Gongylophis conicus, has a color pattern that often looks a lot like that of the Russell's viper, even though it is completely harmless.See also
Cited references
Other references
- Adler K, Smith HM, Prince SH, David P, Chiszar D. 2000. Russell's Viper: Daboia russelii not Daboia russellii, due to Classical Latin rules. Hamadryad, 25(2): 83-85.
- Dowling HG. 1993. The name of Russel's viper. Amphibia-Reptilia 14: 320.
- Groombridge B. 1980. A phyletic analysis of viperine snakes. Ph-D thesis. City of London: Polytechnic College. 250 pp.
- Groombridge B. 1986. Phyletic relationships among viperine snakes. In: Proceedings of the third European herpetological meeting; 1985 July 5-11; Charles University, Prague. pp 11-17.
- Lenk P, Kalyabina S, Wink M, Joger U. 2001. Evolutionary relationships among the true vipers (Reptilia: Viperidae) inferred from mitochondrial DNA sequences. Molecular Phylogenics and Evolution 19(1):94-104.
- Shaw G, Nodder FP, 1797. Naturalists miscellany 9: plate 291.
- Shortt. 1863. A short account of the viper Daboia elegans (Vipera Russellii). Annals and Magazine of Natural History, London. (3) 11: 384-385.
- Wolfgang W, Otsuka S, Malhotra A, Thorpe RS. 1992. Population Systematics of Russell's Viper: A Multivariate Study. Biological Journal of the Linnean Society 47 (1):97-113.
External links
- [DRVVT test information]
- Integrated Taxonomic Information System - [Daboia]
- Genus [Daboia] at the [EMBL Reptile Database]
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