:''Common names: Shedao island pitviper,
[Gumprecht A, Tillack F, Orlov NL, ]Captain A
Captain is a title, an appellative for the commanding officer of a military unit; the supreme leader of a navy ship, merchant ship, aeroplane, spacecraft, or other vessel; or the commander of a port, fire or police department, election precinct, e ...
, Ryabov S. 2004. ''Asian Pitvipers''. GeitjeBooks. Berlin. 1st Edition. 368 pp. . Shedao pit-viper.
[Shine R, Sun L, Kearney M, Fitzgerald M. 2002. Why do Juvenile Chinese Pit-Vipers (''Gloydius shedoaensis'') Select Arboreal Ambush Sites? Ethology 108:897-910. ISSN 0179-1613]
PDF
at University of Sydne
School of Biological Sciences
Accessed 9 August 2006.''
''Gloydius shedaoensis'' is a
venomous
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
pitviper
The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . crotaline snakes (from grc, κρόταλον ''krotalon'' castanet), or pit adders, are a subf ...
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
found only on Shedao Island in
China. Although very small, this island is home to an extraordinarily large population of these snakes. No
subspecies are currently recognized.
Description
Adults grow to an average snout-vent length (SVL) of 65–70 cm (25.6-27.6 inches).
Scalation includes 23 rows of
dorsal scales
In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales
In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down t ...
at midbody, an average of 157
ventral scales
In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...
, and an average of 41 paired
subcaudal scales. Also, the second
supralabial scale is low and does not form the anterior margin of the heat-sensing loreal
pit. The color pattern consists of a grayish brown ground color overlaid with a series of dark brown X-shaped markings. A postocular stripe is present that is very narrow and very dark in color.
[ Gloyd HK, Conant R. 1990. ''Snakes of the ''Agkistrodon'' Complex: A Monographic Review''. Society for the Study of Amphibians and Reptiles. 614 pp. 52 plates. LCCN 89-50342. .]
Geographic range
This snake is found only on Shedao Island off the coast of
Liaotung in northeastern China. The
type locality given is "Shedao (Snake Island), situated about
7.6 statute milesfrom and to the north-west of Lüshun (Port Arthur), Liaoning Province, altitude below 215 m
05 feet (China).
Shedao Island lies 7 nautical miles (about 13 km or 8.1 statute miles) from the nearest mainland and has an area of 0.63 km² (156 acres),
or 0.73 km² (180 acres).
However, despite its small size, the population density of these snakes on the island has long been known to be extremely high. Koba (1938) estimated that, on the southeastern part of the island, there was about one snake for every square meter (10.8 sq ft), while Huang (1984) calculated that there were about 9,100–11,500 snakes on the island during the spring and fall of 1982 when the snakes were active.
Feeding
The diet consists of small
passerine
A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by th ...
birds of various species.
These birds migrate to and from their breeding grounds in
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
and visit the island in May and September. The snakes prey on the birds during these months and are inactive for the rest of the year.
Prey is ambushed either on the ground or from tree branches, the snake waiting with the anterior portion of its body in a concertina shape. Researchers have found specimens in this position, already containing two or three freshly ingested birds. Larger snakes on the ground also scavenge birds that have been struck and killed by other snakes too small to eat them.
References
Further reading
*
Zhao, Er-mi. 1979. A new ''Agkistrodon'' from Shedao (Snake Island), Liaoning.
n Chinese with English summaryActa Herpetologica Sinica 1 (1): 4-6. (''Agkistrodon shedaoensis'')
External links
*
A review on the Shedao pit-viper
{{Taxonbar, from=Q1008096
shedaoensis
Endemic fauna of China
Snakes of China
Reptiles described in 1979
Taxa named by Zhao Ermi