SNAKE VENOM AND THEIR EFFECTS
The venom of the snakes is a complex mixture of generally two types of proteins, each distinguishable by its activity. Antivenin is available which can neutralize the effects of snake venom. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
One category of venom is the neurotoxins. These venoms affect the nervous system, causing destruction or paralysis of the nerves that regulate heartbeat and respiration. Victims may die from asphyxiation or heart failure.
The other major group is the hemotoxic venoms with proteins that attack blood cells and also destroy both muscular and vascular tissue. Hemotoxic venoms allow blood to escape into the surrounding tissue, causing severe swelling, pain and discoloration at the site of the snakebite. Victims may die from shock.
All snake venom has both neurotoxins and hemotoxins. The venom of vipers and pit vipers is primarily hemotoxic with only a small neurotoxic component and causes pain, blistering, hemorrhaging and digestion of tissue around the bite wound. The venom of cobras, kraits and sea snakes contains a higher percentage of neurotoxins. Their venom produces much less obvious symptoms but can affect nerves far removed from the site of the bite.
Venomous snakes are found throughout Pakistan. Assume that any snake you encounter is venomous: Leave it alone and unmolested! As tactical situations permit, avoid high risk habits. Locate bivuacs away from piles of brush, rocks or other debris. Avoid swimming in coastal areas where sea snakes abound. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
1) Practice “snake smart” behavior. Shake out bedding and clothes before use. Sleep off the ground, if possible. Know that thick leather boots offer the best foot protection. 2) Avoid walking alone, especially during the period from dusk to complete daylight. Keep to clear paths. 3) Be alert in areas where snakes may be hiding or sunning. Don’t reach or place parts of body into uninspected places, especially in high grass or among rocks.
4) Remove woodpiles, rock piles, construction debris, dumps, dense undergrowth and similar shelter for snakes. Store supplies elevated off the ground. Practice good sanitation. Control rodents. 5) Keep hands off of rock ledges. Never sit on or step over large rocks or logs without first checking to see what is on the other side. 6)In the unit compound, keep doors, windows and vents closed whenever possible. Block holes in foundations, crawl spaces, ceilings and roofs.
What to Do If Bitten By a Snake: 1) Avoid panic! Move victim out of danger and place at rest. 2) Reassure and calm the patient. 3) Remove rings and constrictive items. 4) Lightly immobilize injured part in functional position. 5) Transport victim to medical facility as soon as possible. 6) Retain snake for identification if possible. 6) Remediate conditions which attract snakes.
Cobras are recognized by the hoods that they flare when angry or disturbed; the hoods are created by the extension of the ribs behind the cobras’ heads. The Indian cobra has a wide black band on the underside of the neck, and a hood marking design which shows half-rings on either side of the hood; the Oxus cobra lacks this distinctive hood marking. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
Cobras in the Afghanistan/Pakistan region are more active during the early evening and early morning. Cobras can be very aggressive when they are protecting their nest and eggs. Oxus and Indian cobras do not “spit” venom but when biting they hold on and chew savagely. Common kraits are smooth, glossy bluish-black snakes with narrow white cross bands and the rounded head slightly distinct from the neck. The body color varies from a dark steely blue-black in a specimen which has freshly shed its skin to a pale faded bluish gray in one just about to shed.
Cobras are at home in many types of terrain. Flat country with high grass and scattered groves of trees is an optimum habitat for Indian cobras. Rice fields and other sorts of agricultural land may support many Indian cobras, and they are often common around villages and cities. Here they may be found in crumbling walls, old buildings, and gardens. Oxus cobras occur in the stony, rocky, shrubcovered foothills along the northern frontier of Pakistan across Afghanistan and into eastern Iran and southern parts of Russian Asia. In some areas, they are found at elevations above 3,000 meters. Oxus cobras are commonly encountered in empty buildings and overgrown fields, especially in areas with abundant rodent populations.
Cobras in Pakistan
Two subspecies of cobras are found in Pakistan, the Indian or spectacled cobra (naja naja naja) and the Central Asian or Oxus cobra (naja naja oxiana). Both these subspecies of cobra are about the same size. Average length is 1.9 meters, with a maximum length of 2.4 meters. N.n.naja has a spectacled marking on back of the neck (also visible from front on rare specimens). The hood appearance varies greatly. The body coloration is yellow to dark brown and black for both sexes. Males are generally heavier, shorter than females, but tails longer. N. oxiana is similar in appearence, but lacks the spectacle marking as in N.n.naja. [Source: Wildlife of Pakistan /+/]
This cobra is diurnal; mostly active during evening and early morning. It may enter human dwellings when hunting. Normaly, it is not considered aggressive and will avoid confrontation with humans. But, when threatened or cornered, will lift upper body, and will spread its hood. When bitting, it hold on and chews savagely. May strike repeatedly. This snake can be exceptionally quick-moving and agile. The fangs and venom glads of both sub-species are large. The venom is highly toxic. Snake bite symptoms begin approximately 8 minutes after bite. Victims experiences anxiety, the pulse quickens, grows weak and irregular. The victim soon falls into deep coma. /+/
The Indian Cobra is found in desert areas, but it prefers areas with some vegetation, such as damp grassland, which often occurs around villages or areas with some cultivation. N.n.naja is found in eastern Pakistan as far west as Karachi. It may be found in flat grasslands, among scattered trees, near rice fields and other cultivated areas, near settlements. Usually not found in deserts or rainforests. It occurs at sea levels and higher elevations. This cobra sub-species is found in Punjab, Balochistan and Sindh where it is quiet common. N.n.oxiana is rare in Pakistan and is found in Northern Pakistan at areas of elevations as high as 2,100 meters. It is found in N.W.F.P and Balochistan The main threat to this snake is from snake charmers who capture it each year to stage fights with moongooses in rural and urban areas.
Common kraits (Bungarus caeruleus sindanus) usually prowl on hot, humid nights and are quite agile in their movements. They have a tendency to seek shelter in sleeping bags, boots, and tents. Specimens disturbed during day rarely bite, but at night they are extremely dangerous and aggressive. This snake is of special concern to soldiers. It’s venom is about 15 times more deadly than the Indian cobra. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
Common kraits are found in a variety of habitats at low and moderate elevations, most commonly in open country, cultivated areas, and scrub jungles up to 1,700 meters elevation. They are often found near human habitations and frequently enter poorly constructed or dilapidated buildings. Kraits and cobras generally avoid very rocky or sandy terrain and desert areas.
The Indian or Sindh Krait (Bungares caeruleus sindanus, local name: sung choor (Urdu)) is found mostly in Pakistan and some part of Iran and Afghanistan. The average length of this snake is 1.0 meters with a maximum lenght of 1.8 meters. It is moderately slender. Has a smooth. glossy appearance. The color varies. It can be blue-black, pale bluish-gray, steel blue, brown, uniformly black. There are paired narrow white, yellow, or grayish crossbands. Young specimens may have white spots instead of crossbands along first one-third of body. The underside is white. The head is egg-shaped, slightly distint from neck. The eyes are small, snout short, upper lip white or yellow and teh tail is short with the tip pointed. [Source: Wildlife of Pakistan /+/]
This snake is nocturnal. It is very active and agile at night. It often hides in rodent holes, loose soil, beneath debris, so is rarely seen during day. When agitated, it will coil up with head concealed, body flattened, and make jerky movements. May also lift its tail. Reluctant to bite, but may make a quick snapping bite. Generally docile, unaggressive during day, but may become aggressive during night. This is the most dangerous of Bunguarus species. The venom is highly toxic. It bites rarely, but in one study 77 percent of victims died. /+/
The Indian Krait is found in Pakistan from coastal lowlands north and eastward to Waziristan and Quetta regions. Also found near southwestern Pakistan coast not far from Iran-Pakistan border. This snake is found in dry open plains, in termite mounds, in burrows of small rodents, beneath debris, at elevations as high as 1,700 meters. It needs ample water supply, so may be found in moist and wet areas such as wells or tanks containing water. Often found near or in human habitation.
Haly’s pit viper (Agkistrodon halys) and Himalayan pit viper (Gloydius himalayanus) are small snakes, with a total length around 90-100 centimeters long. The color of the skin varies from gray, brown to red, dark green or even black. The pit vipers are generally considered to be the most advanced family of snakes since they possess a very sophisticated venom delivery system. Large tubular fangs are placed in the front of the mouth and they are hinged, allowing them to be folded back when not in use. Their heads are covered with numerous small scales and their eyes have vertically elliptical pupils. Pit vipers have a pair of heat sensing pits located between each eye and nostril. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
Their venom is primarily hemotoxic, causing pain, blistering, hemorrhaging, and digestion of tissue around the bite wound. These snakes are mainly nocturnal, resting during the day beneath stones or shrubs, and during warmer months, emerging only after sunset. Reports vary as to aggressiveness. Pit vipers usually will not strike unless continuously disturbed or hurt, but have been known to bite with only minor provocation. Pit vipers are active from the end of March until October.
Pit vipers live in a variety of habitats from desert shrub to short grass or wooded steppes, coniferous forests, and mountainous areas at elevations of 1,500 to 5,000 meters. Favored habitats include dry, rocky areas, and they are often abundant around rocky bluffs that serve as hibernating dens. Often seen close to hiding places where they retreat when disturbed. Pit vipers take refuge under fallen timber, crevices in or under rocks, beneath boulders, ledges, stones, and fallen leaves.
Vipers typically have broad, triangular heads with narrow neck and wide body. Most species are also heavy-bodied with relatively short, slender tails and have numerous and heavily keeled body scales, vertically elliptical eye pupils and a heat sensing organ between eye and nostril. Their long fangs permit deep penetration and envenomation of prey. Their venom is primarily hemotoxic, some with a neurotoxic component, and cause pain, blistering, hemorrhaging, and digestion of tissue around the bite wound. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
Asian sand vipers are active during twilight and at night.These snakes resort to a side winding movement when hurried or alarmed. When agitated, sand vipers hiss loudly, raise their head and a loop of their body well above ground, and strike with great vigor. Persian horned vipers have a typical bulky viper-like body, with a very broad head with short horns above the eyes. Generally nocturnal, they are sluggish, placid, and less likely to bite during day, but dangerously active and aggressive at night.
Persian horned vipers have a characteristic side winding locomotion method. They frequently hide in rodent tunnels and underneath rocks. The Levantine viper has a generally dusty appearance, and is light gray in color with small, rectangular brown, reddish, or dark gray blotches. These snakes are primarily nocturnal, but are quite alert and will strike quickly during the day. Their temperaments are unpredictable, and they may strike quickly and savagely at any time.
ASIAN SAND VIPER Eristocophis macmahonii PERSIAN HORNED VIPER Pseudocerastes persicus RUSSELL’S VIPER Daboia russelii SAW-SCALED VIPER Echis carinatus SAW-SCALED VIPER Echis carinatus sochureki LEVANTINE VIPER Vipera lebetina VIPERS/PIT VIPERS Long, hinged fangs that tuck into roof of mouth when not in use.
Saw Scaled Viper (Carpet Viper)
The saw scaled viper (Echis Carinatus, carpet viper, local name: lundi (Urdu)) is considered to be the world's most dangerous snake because of its highly toxic venom, its abundance near cultivated areas, and its aggressive, easily excitable temperament. This snake is an inhabitant of desert areas. It is found in large numbers in deserts and dry areas and is also found in sandy areas, rocky areas, and scrub forests from sea level to about 1,800 meters. In Pakistan it is found in Thar and Cholistan deserts in Sindh and Punjab and also Astola island off Markan cosat in Balochistan.
Saw-scaled vipers are rough-scaled snakes with large eyes, a head wider than the neck and a stocky body. Their scales are heavily keeled. The body is brown, grayish or sandy with a darker zigzag pattern on the back and a distinct cross or lance mark on the head. Most species are generally nocturnal during hot dry weather; during the day they are found under rocks, in mounds of dead plant stalks, or in bushes up to height of 2 meters or more. Saw-scaled vipers assume a defensive figure eight coil when encountered, rubbing body scales together to produce a distinctive rasping sound. These snakes are involved in many snakebite incidents and numerous fatalities almost everywhere throughout their range, and are considered to be some of the most dangerous snakes in world because of their venom toxicity and high population densities. Saw-scaled vipers are extremely short-tempered, aggressive, and will strike without provocation. They usually try to escape when encountered, but they have been reported to chase victims aggressively. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
There are several sub-species of the saw scaled viper in Central Asia. Echis carinatus sochureki is found in Pakistan, Iran and Afghanistan. The average length is 0.4 to 0.6 meters. the body is slender to moderately stout and slightly flattened vertically. The head is short, distinctly wider than neck and has alight-colored trident, cruciform or arrow-shaped mark on the head. There is a pale stripe from each eye to angle of mouth. The throat and chin are white. The topside of E.carinatus is buff or tan, to olive brown or chestnut with dark-edged whitish spots along backbone, narrow, undulating white line alongs sides (upper portions of loops more conspicuous than lower portions). The underside is white, grayish-white, yellowish-white, pale pinkish-brown, stippled with dark gray. The tail is short, tapers abruptly and is about 10 percent of total body length. [Source: Wildlife of Pakistan /+/]
This snake is primarily nocturnal in hot weather (may be active at dusk) and is sometimes diurnal in cool weather. It may be found basking during early morning in bushes more than 2 meters above ground. It basks in open during cooler weather, but is found more frequently under rocks or in mounds of dead plant stalks. This snake can bury itself in sand with only the head exposed. It is fairly active and can move rapidly in a side winding motion. In dry weather it hunts prey almost entirely at night, but may hunt by day in cool weather. Always alert this snake can become easily excited. It can be really aggressive and is likely to flee when encountered, but has been reported to chase victims aggressively. When threatened is assumes a defensive figure as a C-Coil, rubbing inflated loops of body together to make a distinctive hiss-like rasping sound. Strikes quickly and repeatedly with considerable reach for a small snake.
Russell’s vipers (Vipera Russelli, local name: koriwala (Urdu)) are one of the most dangerous snakes of the Afghanistan/ Pakistan region. These snakes are shorttempered and very aggressive. When disturbed, they strike with great force and speed. Russell’s vipers are medium-sized to large snakes with strongly keeled scales, a distinctive bright chain pattern, and a large triangular head. They are predominately nocturnal but active by day during cool weather. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
Russell's viper have an average length of 0.7 to 1.3 meters and a maximum length of 1.7 meters. The head is rather long, triangular, slightly distinct from neck, with large, conspicuous nostrils on side of snout. The Fangs are large and the tail short. The ground color may be dark brown, brownish-yellow,, or brownish-gray. Immature specimens are usually clear orange to brownish-orange. Dorsal pattern consists of black or brown oval spots edged with black, white, or both. Spots in middle row may fuse together to form zig-zag pattern. Two rows of oval spots run along each side of body. The tail is striped. Belly pinkish-brown or whitish with black spots; becoming darker towards tail. Three seperate semi triangular spots on top of head are situated to form triangle with vertex between eyes. A dark band runs diagonally from eye to corner of mouth. [Source: Wildlife of Pakistan /+/]
This snake is primarily nocturnal (especially during hot weather). Lethargic during day, but can be quiet active at night. It shelters in rodents burrows, old termite mounds, rock crevices, piles of leaves, or other debris. Also found near human dwellings searching for prey. May be active during day in cool weather. Can be very excitable. Coils and will hiss when disturbed. When excited, body will vibrate and emit a low rasping sound resulting from scales of one part of coiled body rubbing upon another. It generally strikes only at objects within its effective striking range, but may strike quickly without provocation. The venom of this snake can deliver 2 to 3 times the lethal venom dose and causes most of the snakebite fatalities in the areas where it occurs. The places Russell’s viper inhabits varies. It is not found in dense forest or permanent marsh. It occurs in plains, savannahs, foothills, montane areas (moist, cool upland slopes below timberline) to elevations of 2,200 meters. /+/
Russell’s vipers occur throughout eastern Pakistan, living in rice paddy fields and other agricultural land, as well as open, rocky, bushy, or grassy terrain up to elevations of 3,000 meters. Saw-scaled vipers are very abundant and inhabit most of the desert and dry areas of Afghanistan and Pakistan. They can live far from any water source and are found in barren, rocky, and sandy deserts, and dry scrub forests, from the sea level to an elevation of about 2,000 meters. They may enter human dwellings in search of prey. Asian sand vipers are found almost exclusively on sand dunes or desert regions at elevations below 1,200 meters. Persian horned vipers inhabit flat, sandy regions and rocky areas up to elevations of 2,000 meters. Levantine vipers live in a wide variety of habitats from marshes and plains at sea level to mountainous areas at elevations up to 2,000 meters and are often encountered near farms and grazing areas. They also inhabit semi-desert areas and rocky, hilly country at moderate elevations, with scattered bushes and adequate water supply.
Sea snakes differ in appearance from other snakes in that they have an oar-like tail and laterally compressed bodies to aid in swimming. A specialized lung and nostrils with valves enable them to remain submerged for periods of up to 8 hours. Most sea snakes are completely marine and lack the enlarged ventral scales that enable land snakes to grip the ground. Once ashore, these ocean-going snakes are helpless, and cannot crawl. Most species are dark above and lighter below, or ringed with black and grayish green. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
They feed on small fish and are preyed upon by sea birds, sharks, and larger fish. Because of their marine environment, sea snakes seldom come in contact with humans. The exceptions are fisherman who capture these dangerous snakes in fish nets and scuba divers who swim in waters where sea snakes are found. Serious envenomations by sea snake bite is, however, extremely dangerous and potentially fatal. Some species of sea snakes have venom several times more toxic than the cobra’s. Their venom is a potent nerve toxin that acts by blocking transmission of messages from nerves to muscles. Fatal bites result in death from respiratory, heart, or kidney failure.
The greatest numbers of sea snakes are found in the warm shallow waters, without strong surf or current, along the Arabian Sea coast. The mouths of rivers, bays, and mangrove swamps are especially favored. Many species of sea snakes enter brackish or fresh water occasionally. [Source: United States Army, Center for Health Promotion and Preventive Medicine (USACHPPM), Entomological Sciences Program, Aberdeen Proving Ground, Md 21010-5403]
Some species of sea snakes that inhabit the deeper ocean waters are only rarely found close to shore, when wind or currents cause beach strandings.
Astrotia stokesii Stoke’s Sea Snake
Enhydrina schistose Beaked Sea Snake
Hydrophis caerulescens Dwarf Sea Snake
Hydrophis cyanocinctus Annulated Sea Snake
Hydrophis lapemoides Arabian Gulf Sea Snake
Hydrophis mamillaris Broad Banded Sea Snake
Hydrophis ornatus Reef Sea Snake
Hydrophis spiralis Yellow Sea Snake
Lapemis curtus Shaw’s Sea Snake
Microcephalophis cantoris Cantor’s Sea Snake
Microcephalophis gracilis Graceful Small-Headed Sea Snake
Pelamis platurus Yellow-Bellied Sea Snake
Thalassophina viperina Schmidt’s Sea Snake
The Indian python (Python molurus, local name: azdaha (Urdu)) is mainly a jungle dweller, but in Pakistan it is found in vegetation near rivers and lakes. The major threat to the Indian python is a familiar one: loss of habitat to expanding human populations. Their favorite habitat was scrub land, considered waste land by local people. But with the introduction of modern farming methods in such areas are being converted for agricultural use. Now it is only found in Southern Sindh, where its numbers are diminishing. Only a few pythons have been reported in district Sanghar in Sindh. It is also hunted indiscriminately for its precious skin. [Source: Wildlife of Pakistan /+/]
The Indian python is one of the world's largest snakes, sometimes reaching lengths of more than 20 feet. Pythons prey on birds and other reptiles, but they prefer small mammals, such as rats. In many parts of their remaining natural range, pythons keep rodent populations in check — a valuable ecological role that is generally unappreciated by local human inhabitants. Pythons — like snakes everywhere — tend to be regarded as dangerous and are often killed on sight. The Indian Python does not wriggle like other snakes, but moves by wave-like movements of its ribs. It is not poisonous and kills its prey by constriction with its body coils, before swallowing its victim head first. It is an good swimmer as well.
Image Sources: Wikimedia Commons
Text Sources: New York Times, Washington Post, Los Angeles Times, Lonely Planet Guides, Library of Congress, Pakistan Tourism Development Corporation (tourism.gov.pk), Official Gateway to the Government of Pakistan (pakistan.gov.pk), The Guardian, National Geographic, Smithsonian magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Wikipedia and various books, websites and other publications.
Last updated February 2022