Deinagkistrodon

Common names: sharp-nosed viper, snorkel viper, hundred pacer,^[2] Chinese moccasin.^[3] more.

Deinagkistrodon is a monotypic genus^[4] created for a venomous pitviper species, D. acutus, found in Southeast Asia.^[1] No subspecies are currently recognized.^[5]

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Description

  Adults grow to an average length of 91-121 cm,^[2] with the largest specimen on record measuring 154.5 cm.^[6] The head has a pronounced soft "horn" on the snout, the length of which varies. It is because of this rostral appendage that the species is sometimes referred to as a "snorkel viper."^[2]

The color pattern consists of a grayish or reddish brown ground color overlaid with a series of brown or reddish brown lateral triangles with grey or beige centers. These join middorsally giving the appearance of alternating triangles of different colors. The head is dark brown on top and beige or pinkish on the sides.^[2]

Common names

Sharp-nosed viper, snorkel viper, hundred pacer,^[2] Chinese moccasin.^[3] Chinese copperhead,^[7] five-pacer, hundred-pace snake, long-nosed pit viper, sharp-nosed pit viper,^[8] hundred-pace pitviper.^[9]

Geographic range

Found in southern China (Chekiang, Fukien, Hunan, Hupeh, Kwantung), Taiwan, northern Vietnam and possibly Laos. The type locality was not included in the original description. It was later given as "Wusueh [Wu-hsueh], Hupeh Province, China" by Pratt (1892) and Pope (1935). Listed as "Mountains N. of Kiu Kiang" in the catalogue of the British Museum of Natural History.^[1]

Habitat

Found on forested mountain slopes, rock-strewn hillsides and brushy valleys.^[2] Occurs at elevations between 100 m and 1,400 m.^[3]

Behavior

This species is mostly active at night or in the evening and spends the day coiled in sheltering rock ledges, among fallen leaves or bracken, in hollow logs and other places where its color pattern keeps it camouflaged.^[2] When encountered it may appear sluggish at first, but it is capable of striking vigorously when threatened.^[3]

Feeding

The diet consists of small mammals, birds and frogs.^[2]

Reproduction

  As one of the few oviparous pit vipers, D. acutus can lay up to 24 eggs, which may be retained during initial incubation -- an adaptation that shortens post-deposition incubation time. Hatchlings are lighter and more vividly patterned than the adults, but this darkens considerably with age.^[2]

Venom

Dangerous animals often have exaggerated reputations and this species is no exception. The popular name "hundred pacer" refers to a local belief that, after being bitten, the victim will only be able to walk 100 paces before expiring. In areas where the snake is regarded as even more venomous, it has been called the "fifty pacer." Nevertheless, this species is considered dangerous and fatalities are not unusual. An antivenin is produced in Taiwan.^[2]

Brown (1973) mentions a venom yield of up to 214 mg (dried) and LD₅₀ (toxicity) values of 0.04 mg/kg IV, 4.0 mg/kg IP and 9.2-10.0 mg/kg SC.^[10]

According to the US Armed Forces Pest Managent Board, the venom is a potent hemotoxin that is strongly hemorrhagic. Bite symptoms include severe local pain and bleeding that may begin almost immediately. This is followed by considerable swelling, blistering, necrosis and ulceration. Systemic symptoms, which often include heart palpitations, may occur suddenly and relatively soon after the bite.^[3]

In popular culture

The snake is also sold as a meal in some Taiwanese restaurants, served with the venom as a drink, pills floating in both the drink and in the snake. The pills are said to counteract the venom.

See also

• List of crotaline species and subspecies
• Crotalinae by common name
• Crotalinae by taxonomic synonyms
• Snakebite

References