Central Asian pit viper is a venomous pitviper species endemic to northern Asia. Three subspecies are currently recognized, including the nominate subspecies described here.
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| Central Asian Pit Viper |
The Central Asian pit viper, with a cadre of closely related and widely distributed subspecies and species, has raised considerable confusion about its taxonomic classification. The snake has "been the subject of considerable taxonomic instability..." as one authority said.
It varies in pattern and color within the specific species. According to some sources, it attacks aggressively, posing a serious danger. According to others, it withdraws timidly, posing little danger. Its venom composition may vary with its locality -- highly toxic according to some, mildly toxic according to others -- posing problems in designing treatment for bites. It has several different common names, for instance, Central Asian viper, Asiatic pit viper, Mongolian pit viper, mamushi and Amur viper, and it also has several different scientific names, for instance, Trigonocephalus intermedius, Ancistrodon intermedius and Haly intermedia. The snake comes with uncertainty in its characterization.
Description
Gloyd and Conant (1990) reported examining subadults and adults of G. intermedius that were 33.5–71 cm (13.2–28.0 in) in total length. Nikolsky (1916) mentioned that some individuals may reach as much as 78 cm (30.5 in) in total length. The body is relatively stout, and the snout is not upturned.
The scalation includes 7 supralabial scales, 23 rows of keeled dorsal scales at midbody, 149-165 ventral scales, and 32-48 subcaudal scales.
The color pattern is variable, but generally consists of 28-45 dark subquadrate dorsal blotches or crossbands that usually extend down the flanks as far as the first or second scale rows. Between these blotches are irregular light areas. A dark brown to black postorbital stripe is present, extending from the eye back to the angle of the jaw, outlined by a light line above, and by cream-colored supralabial scales below.
Distribution, Habitat and Diet
The Central Asian pit viper occurs across a vast range, extending from the Caspian Sea east-northeastward to the Gobi Desert and from northern Iran and Afghanistan northward to southern Russia. It favors rocky grasslands, scrublands and open woodlands, said the Armed Forces Pest Management Board's Living Hazards Database. It "Feeds primarily on rodents, lizards, frogs and large insects," according to Clinical Toxinology Resources. It also likely preys on birds.
Behavior
Given the limited research, the snake raises many questions about its behavior and life cycle. It does, however, seem reasonable that it would follow the model of close relatives within the Viperidae family.
The Central Asian pit viper would likely stay active throughout the day, except in hot weather, when it would become most active around twilight, say some sources. Conversely, it hunts mainly at night, according to Michael Allaby, "Biomes of the Earth: Grasslands." It travels with a sidewinding motion, much like that of the American Southwest's sidewinder rattlesnake. It may ambush prey from a low-lying shrub. If harassed, it may become aggressive, flattening its body against the earth and vibrating its tail in warning preparatory to striking. Otherwise, the snake would behave fairly listlessly.
The snake's courtship behavior seems to be little known, but the female, ovoviviparous, hatches her eggs inside her body, producing, once a year, a litter of some three to twelve, several-inch-long live young. The young Central Asian pit viper, able to feed and defend itself from the start, would mature sexually within a few years. It would breed in the spring or fall. It might live for ten to twenty years.
Venom
According to a study by Shaanxi Normal University graduate students in 2007, the Central Asian pit viper is "the most toxic pit-viper species usually seen in northwest China and part of north China, and it is responsible for the most snakebite accidents in these area[s]." By comparison, said the Armed Forces Pest Management Board, "Not much is known," about the snake's venom, and the snake has inflicted no "confirmed fatalities."
In all likelihood, the snake's venom comprises a cocktail of dozens of proteins and enzymes, a few of them toxic. Likely, said the AFPMB, the venom is both neurotoxic, attacking the nervous system swiftly, and hemotoxic, attacking the cardiovascular system more slowly.
The snake's victims will experience pain, swelling and, possibly, rapid or irregular heartbeat. They may also, said Adrienne B. Ari, Military Medicine, exhibit "the following symptoms: difficulty seeing, seeing double, difficulty in opening the mouth, speaking, and swallowing, and difficulty getting out of bed the morning after the bite," all an indication of the beginning of muscle paralysis. Additionally, suggests Sean P. Bush, MD, Loma Linda University School of Medicine, the victim may experience bleeding into the tissues surrounding the bite. Unfortunately, as the AFPMB said, there is "no known specific antivenom currently available."
Interesting Facts
According to the New World Encyclopedia, there are more than 150 species of pit vipers, which occur in North, South and Central America and in Central and East Asia and Eastern Europe.
A pit viper's heat-sensing pits may be so sensitive that they can detect temperature differences of no more than a few hundredths of a degree Fahrenheit. It can track down and strike prey in utter darkness.
The pit viper's venom delivery system is highly evolved, ranked by many scientists as the most sophisticated in all of nature.
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