Daboia siamensis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Viperidae

Scientific Name: Daboia siamensis (Smith, 1917)
Common Name(s):
English Eastern Russell's Viper
Daboia russelii ssp. siamensis (Smith, 1917)
Vipera russelii ssp. siamensis Smith, 1917
Taxonomic Notes: Until recently, this species was included within Daboia russelii, a species understood to have a widespread but heavily disjunct distribution within South and Southeast Asia. The number of recognized subspecies of this wide-ranging snake is variable, but six are traditionally accepted (Thorpe et al. 2007). Morphological analysis suggests, however, that only two distinct forms exist, one (D. r. russelii) restricted to the Indian subcontinent and the other (for which the name with priority is D. r. siamensis)  found in the remainder of the snake's range (Wūster et al. 1992). These authors refrained from elevating D. r. siamensis to a full species due to the lack of molecular research to support this conclusion. More recently, using both molecular and morphological data, Thorpe et al. (2007) found strong support for this division and recognized two distinct species, D. russelii (incorporating the former subspecies D. r. pulchella and D. r. nordicus as well as D. r. russelii) and D. siamensis (incorporating D. r. limitis, D. r. sublimitis and D. r. formosensis). Due to low divergence between members of each lineage, Thorpe et al. (2007) do not recognize distinct subspecies of either form.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2011-08-31
Assessor(s): Wogan, G.
Reviewer(s): Bowles, P. & Bauder, J.
Listed as Least Concern as this widespread species is highly adaptable, and can be abundant in human-modified habitats. The impact of exploitation, which is heavy in parts of this snake's range, is unclear and requires further investigation, and may warrant reevaluating this snake's status or enacting measures to protect it at local scales.

Geographic Range [top]

Range Description:D. siamensis is found in Central Myanmar, central Thailand, eastern China (Guangxi, Guangdong and Fujian Provinces, and Taiwan) and Indonesia, where it has been recorded from Surabaya in east Java in the Greater Sundas, from Komodo, Flores Solor, Andonara and Lembata in the Lesser Sundas (Thorpe et al. 2007), and recently from east Sumbawa (McKay and Lilley in review). It has an apparently very marginal occurrence in Cambodia; Thorpe et al. (2007) sampled a specimen from Poi Pet, adjacent to the Thai border, but do not include Cambodia in their distribution map for this species.
Countries occurrence:
Cambodia; China (Fujian, Guangdong, Guangxi); Indonesia; Myanmar; Taiwan, Province of China; Thailand
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This widespread species has been reported to be common in some areas. This snake is, however, subject to high levels of both exploitation and persecution in some areas, including its entire range within Myanmar's central dry zone, and so is likely to be undergoing at least localized population declines (G. Wogan pers. comm. September 2011). No quantitative information is available on rates of any declines. In Indonesia, recent records of this species exist only for the islands of Komodo, Flores and Sumbawa; the snake is known from only a single historical record in Java (R.P.H. Lilley pers. comm. October 2011).
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:Unknown

Habitat and Ecology [top]

Habitat and Ecology:This species is not restricted to any particular habitat, and while it is mostly found in open, grassy or bushy areas it may also occur in secondary forests (scrub jungles), forested plantations and farmland. It avoids dense forests and is most common in plains, coastal lowlands and hills. This species is often found in highly urbanized areas and settlements in the countryside, where it feeds on rodents commensal with humans. In Myanmar and Thailand it is commonly collected from paddy fields and other agricultural land. The species is terrestrial and active primarily as a nocturnal forager. However, during cool weather it can be found during the daytime. Adults are reported to be persistently slow and sluggish unless highly agitated, after which they become very aggressive. Juveniles are generally more active and will bite with minimal provocation. While the species feeds primarily on rodents, especially mice, shrews, squirrels, domestic cats, land crabs, scorpions and other arthropods may also be consumed. This species 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 neonates are common.

Use and Trade [top]

Use and Trade: This snake is heavily collected throughout the central area of Myanmar for the international trade, probably for use in medicine in China, and is among the species that forms the bulk of the illegal snake trade from Myanmar (G. Wogan pers. comm. September 2011). In Thailand it is also collected for the skin trade. It is illegal to export snakes from both countries. It is likely that the snake is also subject to heavy exploitation in China, where collection for food and skins is considered a threat (Wang and Xie 2009, as Vipera russellii), although any declines resulting from this exploitation have not been quantified. Dead animals been recorded in markets in Java (M. Auliya pers. comm. December 2011). According to CITES data, between 2000 and 2009, 61,798 skins were exported from wild-collected specimens from Thailand (51,778), Indonesia (10,000) and Laos (20). The same source indicates that a smaller number of leather products reportedly from captive-bred animals are exported from Thailand.

Threats [top]

Major Threat(s): This snake's range in Myanmar coincides with a regionally extensive network of illegal collection and trade in snakes, within which there is a high demand for this species. Levels of exploitation are probably high enough to represent a major threat to this snake, at least nationally (G. Wogan pers. comm. September 2011). As this snake is also heavily persecuted throughout its range, animals which are not collected and sold are typically killed on sight (G. Wogan pers. comm. September 2011). Collection for international trade may also threaten the Thai subpopulation, and while this snake occurs over wide areas in both countries, its disjunct distribution puts national subpopulations at particular risk of local extirpation if harvesting levels are not sustainable. This snake is subject to both collection (for food and skins) and persecution in China (Wang and Xie 2009), but it is not clear whether the snake is under particular pressure in this country.

Conservation Actions [top]

Conservation Actions: This snake is found in a number of protected areas, including Minsontaung Wildlife Sanctuary and Popa Mountain National Park in Myanmar. It is not protected in any country within its range, and although export from Thailand and Myanmar is illegal, this has not prevented high levels of collection in these areas. The impact of exploitation on both the global population and national subpopulations needs to be further studied, with the snake's population status being of interest in both Myanmar and Indonesia, and research is needed to establish whether harvests are unsustainable.

Citation: Wogan, G. 2012. Daboia siamensis. The IUCN Red List of Threatened Species 2012: e.T201501A2707729. . Downloaded on 25 September 2018.
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