Fig. 4.68 Daboia palaestinae

  Fig. 4.69 Daboia russelli

Distribution

See also link "Distribution" at the top of the page for detailed information.

-Daboia deserti: southern Marocco, Algeria, Tunesia, Lybia

-Daboia mauritanica: Marocco, Western Sahara, northern Algeria, Tunesia

-Daboia plaestinae: Israel, Lebanon, Jordan, Syria

-Daboia russelli russelli: eastern Pakistan, India, Bangladesh

-Daboia russelli pulchella: Sri Lanka and southern India

-Daboia siamensis siamensis: Myanmar, Thailand, Cambodia, southeastern China (Guanxi, Guangdong and southern Fujian)

-Daboia siamensis formosensis: Taiwan  
-Daboia siamensis limitis: small areas in Indonesia: eastern Java, Komodo, Flores, Lomblen, Endeh, Adonara and Solor

  Map 51

Daboia russelii:
  Daboia russelli russelii

  Daboia russelii pulchella

Daboia siamensis:

  Daboia siamensis siamensis
  Daboia siamensis formosensis
  Daboia siamensis limitis

Biology

'Russell's viper' group:

Russell's vipers have a large but not continuous distribution area with several isolated populations. The taxonomical division into several subspecies is of even greater medical significance when one considers the different venom compositions, which can cause marked differences in the symptoms of envenoming. Nevertheless the patterns of clinical manifestations show great variations which do not relate either to these conventional subspecies, or to the efficay of antivenoms (Wüster 1998, Thorpe et al. 2007).

Sturdy body, barely over 1 m in length, although some individuals may reach up to 1.5 m. Elongated, triangular head, clearly distinct from the neck, with strikingly large nostrils. Basic colouring dark yellow, fawn or light brown. Belly light with dark spots. In D. russelii (Russell's vipers west of the bay of Bengal) markings consists of three rows of dark ovals that may have a thin, white border around them. These ovals may be distinct from one another or connected to form a "chain". D. siamensis (Russell's vipers east of the bay of Bengal) also has triangular or round blotches between the rows of ovals.

Found from the lowlands to up to 3,000 m in the mountains. Prefers open areas with grass or shrubs, less so stony regions. Never seen in dense forests. As Russell's vipers do not mind wet terrain, it will also enter rice fields in the search for prey. This is where most encounters with humans take place. Also not uncommonly found in other crops, such as pineapple, coconut, sugar cane or rubber plantations. Russell's viper often live close to rural settlements and during its nocturnal phase of activity will also enter houses, although far less frequently than kraits or cobras.

Similar to puff adders in Africa, when in danger they make their presence known through intensive hissing or puffing, produced by forcing air through their nostrils after breathing in deeply. A powerful, incredibly fast strike will follow this threatening warning behaviour.

Other Daboias:

D. deserti, D. mauritanica and D. palaestinae are closely related to the genus Montivipera (asiatic and north African vipers). Large and sturdy species. D. deserti and D. palaestinae up to 1.3 m, D. mauritanica up to 1.8 m. The head is massive, with a distinctly triangular shape, very distinct from the body, tip of the snout is rounded.

Dorsal markings consist of a dark zig-zag or wavy band, in V. palaestinae with a white border. D. mauritanica in shades of brown with a zig-zag or wavy band.

D. palaestinae, the most common venomous snake in Israel, prefers damp habitats and thus often lives in close proximity to agricultural areas, frequently close to human settlements. D. deserti and D. mauritanica in semiarid climate; in stony areas with scarce vegetation, up to 2000 m.

When in danger they hiss and coil their body into a taut S-shape.

Risk

'Russell's viper' group:

Together with the krait and cobra, Russell's vipers are responsible for the vast majority of fatal snakebites in Asia. D. siamensis has great medical significance in Myanmar, where it is responsible for around 85% of all venomous snakebites and 95% of fatal cases of snake envenoming (Aye 1990). Most commonly affected are rural workers who tread on the snakes while working in the rice fields. With around 1,000 victims per year, Russell's viper is the 5th–7th most common cause of all deaths in Myanmar (Aung-Khin 1980).

In neighbouring Thailand, the mortality rate due to snake envenoming is much lower, but fatalities due to D. siamensis in the rice cultivation areas of the central regions of this country do occur. However, in Thailand more people die from envenoming caused by the elapids Bungarus candidus and Naja kaouthia and the pitviper Calloselasma rhodostoma (Looareesuwan et al. 1988).

In Sri Lanka, around 40% of fatal snakebites are caused by D. russelii (D. r. pulchella, De Silva 1976b). There, as in other Southeast Asian countries with large rural populations, the group most at risk are rural workers.

In India, Russell's viper belong to the group of "the big four" significant dangerous venomous snakes, along with cobras (Naja sp.), carpet vipers (Echis carinatus) and kraits (Bungarus sp.). In southern India D. russelii is is the main cause of fatal cases of snake envenoming (Warrell 1989).

Other Daboias:

Most information exists for D. palaestinae. This species is by far the most medically significant venomous snake in Israel. In recent times, the yearly incidence of bites caused by this species has been between 100 and 300, with 0–2 fatalities. Before a specific antivenom became available, the mortality rate was between 6 and 10% (Kochva 1990). Of 61 clinically documented viper bites from the 1940s (most likely all caused by D. palaestinae), 17 had a severe course and 4 patients died (Efrati and Reif 1953).

Allon and Kochva (1974) demonstrated that Palestine vipers possess extremely large amounts of venom. In large specimens, 500 to over 1,000 mg of venom may be contained in their venom glands. On average, a bite from these snakes delivers the considerable quantity of around 50 mg.

Literature (biological)

Aye 1990, Deoras 1978, De Silva 1990, Deuve 1970, Khan 1990, Lenk et al. 2000, Mallow et al. 2003, Minton 1966, Murthy 1990, Saint Girons 1972, Thorpe et al. 2007, Wallach 2014, Warrell 1989, Whitaker and Captain 2004, Wüster 1998, Wüster et al. 1992a/b, Zhao 1990

The Reptile Database