Russell's viper

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Russell's viper
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Genus: Daboia
Species:
D. russelii
Binomial name
Daboia russelii
(Shaw & Nodder, 1797)
Daboia russelii distribution
Synonyms
  • Coluber russelii Shaw & Nodder, 1797
  • Coluber daboie
    Latreille In Sonnini & Latreille, 1801
  • Coluber trinoculus
    Schneider In Bechstein, 1802
  • Vipera daboya Daudin, 1803
  • Vipera elegans Daudin, 1803
  • Coluber triseriatus Hermann, 1804
  • Vipera russelii — Gray, 1831
  • Daboia elegans — Gray, 1842
  • Daboia russelii — Gray, 1842
  • Daboia pulchella Gray, 1842
  • Echidna russellii Steindachner, 1869
Russell's viper (Daboia russelli) in a sensing moment

Russell's viper (Daboia russelii) is a

highly venomous snake in the family Viperidae native to the Indian subcontinent and one of the big four snakes in India. It was described in 1797 by George Shaw and Frederick Polydore Nodder, and named after Patrick Russell
, who wrote about it in his 1796 work An account of Indian serpents, collected on the coast of Coromandel.

Taxonomy

English naturalist George Shaw—with illustrator Frederick Polydore Nodder—in The Naturalist's Miscellany: Or, Coloured Figures Of Natural Objects; Drawn and Described Immediately From Nature formally described the species in 1797 as Coluber russelii, from a specimen presented to the British Museum by Scottish herpetologist Patrick Russell.[1] Russell had written of the species in his 1796 work An account of Indian serpents, collected on the coast of Coromandel, confirming its highly venomous nature by experimenting on chickens and dogs. He added the native people called it katuka retula poda.[2]

Analysis of morphological and mitochondrial DNA data shows that the eastern subspecies of D. russelii should be considered a separate species, Daboia siamensis.[3]

A number of other subspecies may be encountered in literature,[4] including:

  • D. s. formosensis (Maki, 1931) – found in Thailand (considered a synonym of D. siamensis).
  • D. s. limitis (Mertens, 1927) – found in Indonesia (considered a synonym of D. siamensis).
  • D. r. pulchella (Gray, 1842) – found in Sri Lanka (considered a synonym of D. russelii).
  • D. r. nordicus (
    Deraniyagala
    , 1945)     – found in northern India (considered a synonym of D. russelii).

The correct spelling of the species, D. russelii, has been, and still is, a matter of debate. Shaw and Nodder (1797), in their account of the species Coluber russelii, named it after 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 et al. (1999) are among those who favor the original misspelling, citing Article 32c (ii) of the International Code of Zoological Nomenclature. Others, such as Zhao and Adler (1993) favor russellii.[5]

Etymology

The species is named after

herpetologist who first described many of India's snakes, and the name of the genus is from the Hindi word[specify] meaning "that lies hid", or "the lurker".[7]

In English, common names of D. russelii include Russell's viper,[4][8][9][10] chain viper,[8][10] Indian Russell's viper,[11][12] common Russell's viper,[13] seven pacer,[14] chain snake, and scissors snake.[15]

Description

Head of the Russell's viper
Large fangs
Russell's viper in Pune Zoo

The head is flattened, triangular, and distinct from the neck. The snout is blunt, rounded, and raised. The nostrils are large, each in the middle of a large, single

nasorostral scale. The supranasal scale has a strong crescent shape and separates the nasal from the nasorostral scale anteriorly. The rostral scale is as broad as it is high.[4]

The crown of the head is covered with irregular, strongly fragmented scales. The

suboculars. Of the two pairs of chin shields, the front pair is notably enlarged. The two maxillary bones support at least two, and at the most five or six, pairs of fangs at a time: the first are active and the rest replacements.[4] The fangs attain a length of 16.5 mm (0.65 in) in the average specimen.[16]

The body is stout, the cross-section of which is rounded to circular. The

subcaudals numbering 41–68.[4]

Dorsally, 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 the 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 marking that forms an apex towards the snout. Behind the eye 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.[4]

Russell's viper grows to a maximum body and tail length of 166 cm (65 in) and averages about 120 cm (47 in) in mainland Asia. On islands, it is slightly shorter on average.[4] It is more slender than most vipers.[17] The following dimensions for a "fair-sized adult specimen" were reported in 1937:[18]

  • Total length 1.24 m (4 ft 1 in)
  • Length of tail 430 mm (17 in)
  • Girth 150 mm (6 in)
  • Width of head 51 mm (2 in)
  • Length of head 51 mm (2 in)

Distribution and habitat

Russell's viper from India

Russell's viper is found in India, Sri Lanka, Bangladesh, Nepal, and Pakistan. Populations from South-East Asia previously assigned to this species are now considered to be part of a different species,

type locality is listed as "India". More specifically, this would be the Coromandel Coast, by inference of Russell (1796).[5]

Within its range, it can be common in some areas, but scarce in others.

Punjab, very common along the West Coast and its hills, and in southern India, especially in the state of Karnataka and north to Bengal. It is uncommon to rare in the Ganges valley, northern Bengal, and Assam
.

Russell's viper is not restricted to any particular habitat, but does tend to avoid dense forests. The snake is mostly found in open, grassy or bushy areas, but may also be found in

rain forests, are avoided.[4]

This species is often found in highly urbanized areas and settlements in the countryside, the attraction being the rodents commensal with man.[16] As a result, those working outside in these areas are most at risk of being bitten. D. russelii does not associate as closely with human habitation as Naja and Bungarus species (cobras and kraits).[4]

Behaviour and ecology

Russell's viper is

nocturnal forager. However, during cool weather, it alters its behavior and becomes more active during the day.[4]
Adults are reported to be slow and sluggish unless pushed beyond a certain limit, after which they can become very aggressive. Juveniles, though, are generally more nervous.[4] When threatened, they 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.[4] These snakes are strong and may react violently to being picked up.[19] The bite may be a snap, or they may hang on for many seconds.[16]

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 cues, further supporting the notion that they, too, possess a heat-sensitive organ.[20][21] The identity of this sensor is not certain, but the nerve endings in the supranasal sac of these snakes resemble those found in other heat-sensitive organs.[22]

Reproduction

Russell's viper is ovoviviparous.[17] Mating generally occurs early in the year, although pregnant 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,[4] although fewer offspring may occur, as few as one.[16] The reported maximum is 75[23] in a single litter. At birth, juveniles are 215–260 mm (8.5–10.2 in) in total length. The minimum total length for a gravid female is about 100 cm (39 in). It seems that sexual maturity is achieved in 2–3 years. In one case, it took a specimen nearly 4.5 hours to give birth to 11 young.[4]

Prey

Russell's viper hunting

Russell's viper feeds primarily on rodents, although it will also eat small reptiles,

crepuscular, feeding on lizards and foraging actively. As they grow and become adults, they begin to specialize in rodents. Indeed, the presence of rodents and lizards is the main reason they are attracted to human habitation.[4]
Juveniles are known to be
cannibalistic.[16]

Mimicry

The rough-scaled sand boa Eryx conicus possibly mimics the appearance of Russell's viper

Some

herpetologists believe, because D. russelii is so successful as a species and has such a fearful reputation within its natural environment, another snake has come to mimic its appearance. Superficially, the rough-scaled sand boa Eryx conicus has a color pattern that often looks like that of D. russelii, though it is completely harmless.[4][18]

Venom

Venom of this species is delivered by means of

solenoglyphous dentition.[24] The quantity of venom produced by individual specimens of D. russelii is considerable. Venom yields for adult specimens have been reported as 130–250 mg, 150–250 mg, and 21–268 mg. For 13 juveniles with an average total length of 79 cm (31 in), the venom yield ranged from 8 to 79 mg (mean 45 mg).[4]

The LD50 in mice, which is used as a possible indicator of snake venom toxicity, is: 0.133 mg/kg intravenous,[25] 0.40 mg/kg intraperitoneal,[26] about 0.75 mg/kg subcutaneous.[27] For most humans, a lethal dose is about 40–70 mg, well within the amount that can be delivered in one bite. In general, the toxicity depends on a combination of five different venom fractions, each of which is less toxic when tested separately. Venom toxicity and bite symptoms in humans vary within different populations and over time.[4] In another study, Meier and Theakston reported that the lethality of venom of Russell viper varies with change in route of injection, as their results predicts the LD50 of 0.4 mg/kg through intraperitoneal (I.P) route, 0.75 mg/kg/subcutaneous (S.C) route and 0.3 mg/kg through intravenous (I.V) route.[28]

Symptoms

Envenomation symptoms begin with pain at the site of the bite, immediately followed by swelling of the affected extremity. Bleeding is a common symptom, especially from the gums and in the urine, and

renal failure) also occurs in approximately 25–30 percent of untreated bites. Severe disseminated intravascular coagulation
also can occur in severe envenomations. Early medical treatment and early access to antivenom can prevent and drastically reduce the chance of developing the severe/potentially lethal complications.

Severe pain may last for 2–4 weeks. It may persist locally, 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, envenomation is likely to be massive. Discoloration may occur throughout the swollen area as red blood cells and plasma leak into muscle tissue.

septicaemia or kidney, respiratory, or cardiac failure may ensue 1 to 14 days after the bite, or sometimes later.[16]

A study in The Lancet showed that out of a sample of people who survived bites by D. russelii, 29% suffered severe damage to their pituitary glands, which later caused hypopituitarism.[29] Other scientific studies support the hypothesis that D. russelii bites can cause hypopituitarism.[30][31]

Antivenom treatment

In India, the Haffkine Institute prepares a polyvalent antivenom that is used to treat bites from this species.[16] In late 2016, a new antivenom had been developed by the Costa Rican Clodomiro Picado Institute, and clinical trials were started in Sri Lanka.[32]

Clinical use

Because this venom is so effective at inducing

autoimmune disorder), because it is not influenced by deficiencies in clotting factors VIII, IX or XI.[33]

References

  1. ^ Shaw, George (1797). "The Russelian Snake". The Naturalist's Miscellany. 8: 291–293.
  2. ^ Russell, Patrick (1796). An account of Indian serpents, collected on the coast of Coromandel. Vol. 1. London: W. Bulmer and Co. Shakespeare-Press. p. 10. Archived from the original on 2023-02-10. Retrieved 2020-08-15.
  3. ^ a b Thorpe RS, Pook CE, Malhotra A (2007). "Phylogeography of the Russell's viper (Daboia russelii) complex in relation to variation in the colour pattern and symptoms of envenoming". Herpetological Journal. 17: 209–18.
  4. ^
    ISBN 0-89464-877-2
    .
  5. ^
    ISBN 1-893777-01-4
    (volume).
  6. ISBN 978-1-4214-0135-5
    . (Daboia russelii, pp. 229-230).
  7. ISBN 0-19-861258-3
    .
  8. ^ a b Snakes of Thailand: Venomous snakes Archived 2016-03-30 at the Wayback Machine at Siam-Info Archived 2016-05-06 at the Wayback Machine. Retrieved 20 October 2006.
  9. ^ Daboia russelii at the Reptarium.cz Reptile Database. Accessed 2 August 2007.
  10. ^ a b . Retrieved 20 October 2006.
  11. ^ Captive Care of the Russell's viper Archived 2008-04-09 at the Wayback Machine at VenomousReptiles.org. Retrieved 14 March 2007. Archived April 9, 2008, at the Wayback Machine
  12. ^ Somaweera A (2007). Checklist of the Snakes of Sri Lanka. Peradeniya, Sri Lanka: Department of Zoology, Faculty of Science, University of Peradeniya. PDF Archived 2008-09-20 at the Wayback Machine at Sri Lanka Reptile Archived 2009-08-18 at the Wayback Machine. Retrieved 14 March 2007.
  13. ISBN 0-8069-6460-X
    .
  14. ISBN 0-398-02808-7
    .
  15. ^
    ISBN 0-486-26629-X
    .
  16. ^
    ISBN 0-19-566099-4
    .
  17. ^
    ISBN 0-448-11856-4
    .
  18. ^ a b Ditmars, R.L. (1937). Reptiles of the World: The Crocodilians, Lizards, Snakes, Turtles and Tortoises of the Eastern and Western Hemispheres. New York: The MacMillan Company.
  19. ^ Whitaker Z (1989). Snakeman: The Story of a Naturalist. Bombay: India Magazine Books. 184 pp. ASIN B0007BR65Y.
  20. PMID 12819261. Archived
    from the original on 2023-02-10. Retrieved 2009-11-29.
  21. PMID 15531644. Archived
    from the original on 2023-02-10. Retrieved 2008-02-22.
  22. PMID 9624452
    .
  23. ^ "Russell's Viper delivers 75 snakelets". Bangalore Mirror. Archived from the original on 2020-07-11. Retrieved 2020-07-11.
  24. ^ Mao, Shou-Hsian (May 19, 1967). "Bite Patterns of Taiwan Venomous and Non-Venomous Snakes" (PDF). zoolstud.sinica.edu.tw. Archived (PDF) from the original on December 23, 2021. Retrieved December 23, 2021.
  25. ^ "LD50 - intravenous". Archived from the original on 2011-07-16. Retrieved 2012-01-08.
  26. ^ "LD50 - intraperitoneal". Archived from the original on 2009-07-18. Retrieved 2012-01-08.
  27. ^ "LD50 - subcutaneous". Archived from the original on 2005-02-05. Retrieved 2012-01-08.
  28. PMID 3715904
    .
  29. ^ "The deadly Russell Viper: How the snake's venom affects humans". May 4, 2015. Archived from the original on December 13, 2020. Retrieved November 29, 2020.
  30. S2CID 41839362
    .
  31. PMID 21115460
    .
  32. ^ Rodrigo, Malaka (9 October 2016). "Trials to start for home-grown anti-venom". The Sunday Times (Sri Lanka). Archived from the original on 20 July 2021. Retrieved 20 July 2021.
  33. ^ Antiphospholipid Syndrome Archived 2006-11-17 at the Wayback Machine at SpecialtyLaboratories Archived 2019-04-02 at the Wayback Machine. Retrieved 27 September 2006.

Further reading

External links

Wikispecies has information related to Russell's viper.
Wikimedia Commons has media related to Daboia russelii.

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