Pit Viper

Certain group of snakes do what no other animal or artificial device can do.They form detailed image of extremely small heat signatures,what is most fascinating is that they do this with receptor that are microscopic in size,extraordinarily sensitive,uncooled and are able to repair themselves.

Snakes infra-red imagers are at least 10 times more sensitive than the best artificial infra-red sensor

pit organ afferent  demonstrates that receptors are sensitive to very  small  temperature  changes ( ~0.003 deg Celsius).

HOW DOES THE SNAKE See ?

The detection systems,which consist of cavities located on each side of the head called pit.

The detection system consist of cavities located on each side of head called pit organs,operated on principle similar to that of pinhole camera.Pit viper and boids the tow snake that possess this ability,have heat -sensitive membranes that can detect the difference in temperature between a moving prey and its surrounding on scale of mK.IF the radiation intensity hitting the membrane itself,membrane heats up that location.The picture of such cavities is presented in fig below.

Fi

Figure 1.: Snake heat vision : a)Head of pit viper with nostril,pit hole and eye,left to right

.b) A pit vipers infra-red sensitive pit organ works like a pinhole camera.

According to the Planck radiation law as an approximation of the emitted heat intensity,99% of the radiation is emitted at wavelengths under 75 micrometers and the radiation intensity is maximal at 9.5 micrometers which is within the 8-12 micrometers IR atmospheric transmittance window.

Because the pit hole is very large compared to the membrane size,the radiation strikes many points.Optical quality of the infra-res vision is much too blurry to allow snakes to strike prey with the observed accuracy of about 5 degrees.The most fascinating is an amount of heat-sensitive sensors and their precision.

In Pit vipers,which have only two pit holes ( One in front of each eye ), a block of about 1600 sensory cells lie on membrane which has field of view of about 100 degree.This means the snake's brain would receive an image resolution of about 2.5 degrees for point -like objects,such as eyes,which are one of the hottest points on mammals.

If the aperture was very small,the amount of energy per unit time (second) reaching the membrane would also be small.The need together a reasonable amount  of thermal energy per second necessitates the " Pin Hole " of the pit organ to be very large,thus greatly reducing its optical performance.If on the other to be very large,thus greatly reducing its optical performance .If on the other hand the aperture of the organ is large,the image of a point source of heat is disc-shaped rather than point-like.

Since ,however ,the size of disc-shaped image may be determined by the detectors on the membrane,it is still  possible to tell from which direction the radiation comes ,ensuring directional sensitivity of the system. The aperture size was probably  an evolutionary trade off between image sharpness and radiant flux.Although image that us formed of the pit membrane ha very low quality the information that is needed to reconstruct the original temperature  distribution in space is still available.

So how a snake could possible use such poorly focused IR input to find its prey in darkness with a surprising angular precision of 5 degrees ?How the snake may be able to extract information on the location of the prey from the blurred image that is formed on the Pit-membrane.

WHAT DOES THE SNAKE SEE ?

Without the ability of real time imaging the IR organ would be of little use for the snake.so Dr.Van Hemmen proved that it is possible to reconstruct the original heat distribution using the blurred image on the membrane.

The image on the membrane resulting from the total heat distribution in space will be  some complicated shape that consist of the superposition of the contribution of all heat sources.A superposition of edge detector in the brain can now reconstruct the heat distribution by using the whole image on the membrane for each point in space to be reconstructed so reconstruction is possible because the information is still available in th blurred image on the pit membrane,where the receptor are. As a demonstration of the model image was used

Figure -2: The Famous hare by Durer ( left ) was coverted into 8-bit gray at a resolution of 32X32 (right).
Since a snake has limited computational resources ( all " Calculations"must be realizable in neuronal ' 'Hardware ' ') the reconstruction model must be simple.Our Model thus uses only one computational step ( it is non iterative) to estimate the input image from the measured response on the pit membrane.It resembles a wiener filter and is akin to,but different from,some of the algorithms used in image reconstruction.
So it is highly remarkable that snakes can perform some kind of an image processing like our artificial devices based on " wave front coding" and ' ' Pupil engineering techniques.

IMAGE PROCESSING IN NATURE
There was developed a neuronal algorithm that accurately reconstructed the heat image from the membrane.The Most vital requirements is accurate detectors and the ability to detect edges in the images produced on the pit membrane,.That is similar to the situation   with " wave front coding " device :The dynamic range and accuracy of the ADC is much more important that it is much more important than an amount of elements.

I would like to introduce an analogy here: such imaging like drawing a picture on a sand.The more fine the sand ,the more accurate and delicate pictures one can draw.That is the case of high dynamic range of the detector.And vice cersa: on a coarse and stony sand it is difficult to draw a fine tracery that is the case of low dynamic ranges detector.

But let us get back to the model of snake vision:
The model has a fairly high noise tolerance.For input noise levels up to 50%,the hare is recognizable  Sensitivity  to measurement errors corresponds to about 3 degrees.For detector noise levels up to about 1% of the membrane heat intensity,a good reconstruction is about one pixel accuracy.At detector noise levels beyond about 1% of the membrane heat intensity, a good reconstruction is about one pixel accuracy .At detector noise levels beyond about 1% the image is not so easily recognizable,but the presence of an object is still evident.
The assumptions that went into the calculations are a "worst case scenario".For instance,we assumed that the input to the pit organ is totally uncorrelated, meaning that the snake has no idea what heat distribution to expect.In reality,important information about the environment is always available.For example,typical temperature and size of aprey animal may be encoded in th neuronal processing structure.If the snake " know"what kind of images to expect,the reconstruction process can be enhanced considerably.

How does the reconstruction matrix become imprinted on the snake's neural circuitry in the first place? ``It can't be genetic coding,'' says van Hemmen. ``The snake would need a suitcase full of genes to encode such detail. Besides we know that snakes ...need a season of actual learning, not just anatomical maturation, to acquire their extraordinary skills.''... [11]

On the Fig. 3 it is shown a deconvolution results that give us a concept of the snakes vision capabilities.

Figure 3: On the left, this figure displays the membrane heat intensity as captured by the ``pithole camera''. On the right are reconstructions for four different membrane noise levels. The pit membrane was taken as a flat square containing41x41 receptors. The model works equally well if applied to other membrane shapes. The membrane noise term was taken to be Gaussian with SIGMA= 25, 100, 200, and 500 from left to right and top to bottom, corresponding to 0.25%, 1%, 2%, and 5% of the maximal membrane intensity. The image from the paper [2]

Ultimately, a snake's ability to utilize information from the pit organs depends on its capability to detect edges in the image produced on the pit membrane. If the snake performed no reconstruction, but instead simply targeted bloblike ``hot spots'' on the membrane, it would still have to be able to discern the edge of the blob. The present model performs edge detection for all spatial positions and hence automatically creates a full reconstruction. A level of neuronal processing beyond what is represented in our model is unlikely to be beneficial since the quality of the system is fundamentally limited by the relatively small number of heat receptors.[5]

Conclusion

Snakes' heat vision presents such a clear image when reconstructed that it surpasses even many human devices - it is far better than any technical uncooled infra-red camera with a similar number of detector cells [2].

Russel Viper

Common Name :- Russel Viper

Venom/Non Venom :- Highly Venomous Snake.Third most common venomous species.

Local Name/Marathi Name: -घोनस
Distribution : - All over India ,Not found in North east and Kashmir.
Status :- Common, Most Common Viper in India. 
Average Length:- 100 cm ( 3 feet 3 inch)
Maximum Length:- 180 cm ( 5 feet 11 inch )
Breeding Season:- In Between May to July or Mid August Female give birth to 6-63 live young ( Generally not more than 60 ).
Venom type :- Hemotoxic Venom.

Description


Habitat.
Its not restricted to any particular habitat,but does tend to avoid dense forests.The snake is mostly found in open,grassy or bushy areas,but may also be found in second growth forest( scrub jungles) ,on forested plantations and farmlands. They are most common in plains,coastal lowlands and hills of suitable habitat. Genrally not found at altitude,but has been reported as far up as 2300-3000m. Humid envornment ,such as marches,swamps, and rain forests are avoided.
This species is often found in highly urbanized areas and settlements in the countryside,the attraction being the rodents comensal with man.As a result,those working outside in these areas are most at risk of being bitten.


Behavior
Russell Viper is a nocturnal Species like other Vipers;but can be sighted in scrubs and bushes during day time for basking,during winter it can stay at single place for more than one day for mating and basking.Lives in bushes,scrubs,rocks,dense vegetation,agricultural lands,dry leaves,grass lands,wood piles etc.

Behavior very agile and uncertain on provocation;
First Produce whistle sound ( Like pressure cooker ) as warning sign,will coil its body with head at center of the coil and may attack anytime on further disturbance.Can bite even when its body is elongated while creeping.
Not a very good climber and like to remain on ground for better adjustment with its surroundings.Vary rarely ,if conditions and adverse,it may climb up to a certain height.Once a sub adult was found on hut in the month of December in MP
Feeds on rodents,birds,lizards adn small mammals,No genuine record of cannibalism from this species.
This snake is terrestrial and active primarily as nocturnal forager.However,during cool weather it will alter its behavior and become more active the day.
Adults are reported to persistently slow and sluggish unless pushed beyond a certain limit,after which they become aggressive.Juveniles,on the other hand,are generaaly more nervous.
When threatened they form series of S-loop,raise the first third of the body and produce a hiss that is supposedly louder that that of any other snake.
When striking from this position,they can exert so much force that even a large individual can lift most of its body off the ground in the process.These snakes are strong and may react violently to being picked up.The bite may be snap or they may hang on for many seconds.
Although this genus doesn't have the heat-sensitive pit organs common to the ceotalinae,it is one of a number of viperines that are apparently able to react to thermal cues,further supporting the notion that they too possess a heat-sensitive organ.The identity of this sensor is not certain,but the nerve ending in the supranasal sac of these snakes resemble those found in other heat-sensitive organs

Territory

Feeding Habits ( Food )

Distinctive Feature

Breeding,Housing and Nesting

General Size and Shape

Breeding Season ( Reproduction )

Egg

Importance of Snake

Survival,threats and Danger

Mimicry

Prey

Venom

Symptoms after Bite

Snakes Find In India

As you know Snakes are divided into two types poisonous and non poisonous. By family snakes, fishes, lizards, crododiles, dinosars and birds belong to same group.

Of the over 2000 species of snakes in the world, about 200 are found in India. These range from the worm snakes having a length of about 10 cms. to those more than 6 mts. long. They live in almost all habitats from the warm seas to semi-deserts, swamps, lakes and even in the Himalayan glaciers up to an elevation of about 5000 mts. Thirty main species of Indian snakes have been discribed here. 

Common Worm Snake
( Typhlina bramina): A small worm-like snake found all over India. In the hills, it lives up to an elevation of 1000 mts. 

Perrotet's Shield-tail Snake
(Plectrurus perroteti): A small snake found in the hills along the west coast of India, i.e., The Western Ghats, Nilgiri and Annamalai hills. 

Indian Rock Python
(Python molurus): A large thick-bodied snake found in many parts of India. It ranges from the mangrove forest to arid scrublands and dense rain forest of the eastern Himalayas up to an elevation of about 2000 mts. 

Common Sand Boa
(Eryx conicus): A short thick-bodied snake found in the plains and low hills of India. They are nocturnal and hunt after dark. 

Red Sand Boa
(Eryx johnii): A medium-sized snake with a very blunt tail. It is found in the drier tracts of the country. 

Common Wolf Snake
(Lycodon aulicus): A small slender snake found throughout India. In the hills, it occurs at an elevation of about 2000 mts. 

Banded Kukri 
(Oligodon arnesis): A small snake with prominent cross bands on its body. Found all over India and up to an elevation of 200 mts. in the eastern Himalayan. 

Stripped Keelback 
(Amaphiesma stalata): A small to medium-sized snake that is closely related to and resembles the water snake. Found all over India and up to an elevation of 2000 mts. in the hill. 

Green Keelback 
(Macropisthodon plumbicolor): A medium-sized keelscaled snake found in the forested region of India up to an elevation of 1500 mts. 

Checkered Keelback Watersnake
(Xenochropis piscator): A medium-sized keeled snake found all over India up to an elevation of about 3000 mts. 

Olive Keelback Watersnake
(Altritium schistosum): A small to medium-sized snake found in central and peninsular India up to an elevation about 1000 mts. 

Trinket Snake 
(Elaphe halena): A medium-sized, slender snake found all over India up to an elevation of about 4000 mts. in the Himalayas. 

Rat Snake 
(Ptyas muscosus): A large-scaled snake found all over India up to an elevation of about 4000 mts. It is capable of adapting to almost any environment. They are prodigal rat-eaters. 

Banded Racer
(Argyrogena fasicolatus): A small to medium-sized snake found in the plains of India. It prefers to live amongst tall grass and bushes. 

Royal Snake 
(Spalerosophis diadema): A medium to large-sized snake found in the drier tracts of Rajasthan, Punjab, Haryana, Uttar Pradesh, Jammu hills and Himachal Pradesh up to an elevation of 2000 mts. 

Bronze-back Tree Snake
(Dendrelaphis tristis): A medium-sized slender snake found all over India up to an elevation of 2000 mts. in the Himalayas. They prefer low bushes and thorny trees. 

Flying Snake
(Chrysopelea ornata): A small to medium-sized snake found in the forest of southwest India and northeastern parts of the country north of Bihar and Orissa. They prefer to live on large trees and appear to glide for some distance. 

Vine Snake
(Ahaetulla nasutus): A medium to large-sized snake found all over India, except in the northwest and parts of the Ganga plain. They may occur at elevation of about 2500 mts. preferring low bushes and trees. 

Common Cat Snake
(Boiga trigonata): A small to medium-sized snake found all over India up to an elevation of 3000 mts. in the Himalayas. They are nocturnal in habit and prefer to spend the daylight hours in a cool place. 

Dog-faced Watersnake
(Cerberus rhynchops): A medium-sized snake found in the coastal tracts. They live in muddy and rocky areas in estuaries, mangrove swamps, salt pans and deserted creeks. 

Common Krait
(Bungarus caeruleus): A medium-sized snake with thin white bands on its body. Found almost all over India up to elevation of about 1700 mts. They are nocturnal in habit. 

Banded Krait
(Bungarus caeruleus): A medium to large-sized snake with prominent yellow and black bands on its body. Found in northeast India, Bihar, Orissa, Madhya Pradesh, Andhra Pradesh and Uttar Pradesh up to an elevation of 1500 mts. 

Sleder Coral Snake
(Callophis melanurus): A small slender snake found in most parts of the country except parts of central and northeast India, Bihar, Orissa, Madhya pradesh, Andhra Pradesh and Uttar Pradseh up to an Elevation of 1500 mts. 

Indian Spectacled Cobra
(Naja naja naja): A medium to large-sized snake found all over India up to an elevation of about 4000 mts. in the Himalayas. They feed on frogs, toads, rodents, birds and small snakes. 

Indian Monocled Cobra
(Naja naja kaouthia): A medium-sized snake found in northeast India, parts of Uttar Pradesh , Bihar, Orissa and West Bengal. They are mainly nocturnal in habit. 

King Cobra
(Ophiophagus hannah): A large-sized snake that may be up to 5 mts. in length . It has distinct cross bands on its forebody. Found in dense forests of South India, Himalayan foothills up to an elevation of 2000 mts., Orissa , Bihar, West Bengal and North east India. 

Hook-nosed Sea Snake
(Enhydrina schistosa): A medium-sized snake with a flattened body and tail. Found along the coast and coastal islands. They are seasonally found in the deep sea though they prefer coastal areas. 

Russell's Viper
(Vipera russellii) : A medium to large-sized snake with a characteristic bright pattern on its body. Found all over India, both in the plains and hills up to an elevation of about 3000 mts. 

Saw-scaled Viper
(Echis carinatus): A small-sized snake found all over India, usually in the plains. They may occur in areas as high as 2000 mts. in the northwestern Himalayas. 

Bamboo Pit Viper
(Trmeresurus gramineus): A small-sized snake with a triangular head. Found in the hills of central and eastern India. It prefers cold, thick vegetation along watercourses and bamboos and other dense foliage. 

Some Other Common Snakes Of India
1. Slender Worm Snake (Typhilina porrectus) 2. Pied-belly Shield-tail Snake (Melanophidium punctatum) 3. Nilgiri Shield-tail Snake(Uropeltis ocellatus) 4.Regal Python (Python reticulatus) 5. Khasi Earth Snake (Stoliczkaia khasiensis) 6. Olive Forest Snake (Rhabdops olivaceus) 7. Glossy Marsh Snake (Gerarda prevostiana). 

POISONOUS SNAKES OF INDIA:

Indian (Spectacled) Cobra - Naja naja naja

Distinctive Features: Medium-sized to large; smooth, shiny scales; wide head and neck; wide black band on underside of neck; distinctive hood marking on top of neck.

Description: The Spectacled Cobra is a smooth-scaled snake with black eyes, wide neck and head and medium body. Colouring varies form black or dark brown to yellowish white. The underside is usually white or yellowish with a wide dark neck band. The body is generally covered with a speckled white or yellow pattern, sometimes forming ragged bands. The famous hood marking of the classic design, shows a connected pair of rings. Occasionally, it may not even resemble spectacles, or may be altogether absent. The cobras of northwest India are blackish and have a barely distinguishable hood marking. Cobras are often confused with the Indian rat snakes, which have a much thinner neck and head, and become 3 metres long, a metre more than do the biggest Indian cobras.

The Spectacled Cobra is the most widely distributed of the generally accepted 3 sub -species of cobras in Indian and is one of the big four dangerous snakes, 6 species of cobras occur in Asia and 9 in Africa. The jet black cobras occur in Asia and 9 in Africa. The jet black cobra of northwest India and Pakistan is another sub-species or geographic race. Except for its colour and absence of hood marking, it is very similar to the spectacled Cobra.

Distribution: Throughout India, sea level upto 4000 m (in the Himalayas)


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King Cobra - Ophiophagus Hannah

Distinctive Features: Large; smooth, shiny scales; distinct light cross bands mainly on the forebody; large head scales edges with black.

Description: The large head of the giant King Cobra is little wider than the neck. The head scales are edged with black and the overall colour varies from yellowish to deep olive-green but the tail if often jet-black. The underside is a lighter shade of the body colour. The yellow bands on the snake's back are more obvious in the light coloured specimens from Orissa and Uttar Pradesh. King Cobras are the largest venomous snakes in the world.

Distribution: Rare in India, King Cobras are confined mostly to the dense forests of the Western Ghats and the northern hill forests. Nilgiris, Plains and Western Ghats upto Goa, the Himalayan foot hills (upto 2000 m) starting near Lahore in Pakistan through North Indian to Assam. Forests of Orissa, Bihar, West Bengal and the Andamans.


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Banded Krait - Bungarus fasciatus

Distinctive Features: Medium-sized to large; smooth, shiny scales: wide bright yellow and black bands on back.

Description: The Banded Krait is a large, conspicuous yellow and black banded snake with a prominent backbone, blunt tail and rounded head slightly distinct from the body. The bands are faded on the underside.

Distribution: Assam, Bengal, Bihar, Orissa and reported in parts of Madhya Pradesh, Andhra Pradesh and Uttar Pradesh. Found upto 1500 m above sea level.


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Slender Coral Snake - Callophis melanurus

Distinctive Features: small, slender; smooth, shiny scales: blunt, black head; tail black, scarlet and blue.

Description: The Slender Coral Snake is light brown and family speckled. The head and neck are black with two conspicuous yellow spots on the top of the head. There is a ragged black ring at the tail-base and at the tail-up. The underside is uniform pinkish-red (coral), bright scarlet at vent, and the underside of the tail is bluish. The head is blunt and has the same width as the neck; the scales are smooth and slightly glossy. Slender Coral Snakes are one of the 5 Indian coral snakes. The other 4 are hill forest species of the Western Ghats and eastern Himalayas.

Distribution: Reported from the most parts of India on the plains, except central and northwestern India. MacClelland's Coral Snake is found up to 4000 m in the Himalayas.


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The Indian (Monocled) Cobra - Naja naja kaouthia

Distinctive Features: Medium-sized; smooth, shiny scales; wide head and neck; distinctive hood marking different from that of the spectacled cobra.

Description: The skin of the Monocled Cobra is shinier, the hood rounder and smaller and the head smaller than is that of the spectacled cobra. The colour varies widely, from yellowish to greenish brown to black, with ragged bands. There is a conspicuous white monocle on the hood. The underside is yellowish white Monocled Cobras superficially resemble Spectacled Cobras, but there are many small differences.

Distribution: Monocled Cobras are a sub-species most commonly found in northwest India, parts of Uttar Pradesh, Bihar, Orissa and the Andamans, all of Bengal and Assam.


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Russells Viper - Vipera russellii

Distinctive Features: Medium-sized to large; strongly keeled scales; distinctive bright chain pattern; large triangular head.

Description: Russells Vipers are heavy, rough-scaled snakes with vertical eye pupils and generally a very bright pattern. The body colour is usually brown or yellowish and the pattern is composed of dark, round spots edged with white and black. The underside is white in the western, partly speckled in the southeastern and heavily speckled in the northeastern race. Colour variation is common, and the best recognition characters are the short, fat body, the triangular-shaped head and very regular chain like pattern. Russells vipers resemble the fat, harmless common sand boas which however have shorter and blunter tails and irregular body patterns. The bright symmetrical spots on Russells Viper's backs make them easy to differentiate. Russells Vipers are one of the big Four dangerous snakes of India. The other large Indian viper is the Levantine Viper, a heavy brown snake found in parts of Kashmir which grows to 11/2 m.

Distribution: Hills and plains throughout India upto 3,000 m.


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Saw-Scaled Viper - Echis carinatus

Distinctive Features: small; strongly keeled scales; head wider than neck; dull colour; cross mark on top f head distinctive.

Description: A rough scaled snake with large eyes, wider head than neck and stocky body. The 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. The underside is white with brown speckles. The tail is short and stubby. Saw-scaled Vipers are the smallest of the Big Four venomous snakes and are less of the threat to man in South India because of the small size of the southern type. The northern for, however, grows large enough to be a potentially dangerous member of the Big four.

Distribution: Throughout India, mostly on the plains. In northwest India, Saw-scaled Vipers are reported from upto 2000m ion the hills. They are plentiful in certain area such as Ratnagiri District in Maharashtra, parts of Punjab, Rajasthan, Tamil Nadir and Andhra Pradesh.


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Common Krait - Bungarus caeruleus

Distinctive Features: Medium-sized; smooth, glossy scales; head slightly wider than neck: jet-black, usually with distinct white cross lines.

Description: Common Kraits are smooth, glossy bluish-black snakes with the rounded head slightly distinct from the neck. The body colour varies from a dark steely blue-black in a specimen which has freshly shed its skin to a pale faded bluish grey in one just about to shed. There are normally about 40 thin white cross bands. The young and some adults may have white spots along the first third of the backbone in place of the cross lines. This variation as well as uniform black variants appear in certain geographic races. The underside is white. Common Kraits are often confused with wolf snakes (Lycodon sp.) which are much smaller, with flat, somewhat pointed heads. The Common Krait is the best known of the 6 Krait species found in India and one of the big Four dangerous snakes. Besides the Common and Banded Krait, the other krait are rare and confined to the eastern Himalayas and Assam.

Distribution: Most of India including the Andaman and Nicobar Islands: sea level up to 1700 m. uncommon in Bengal, Assam and Orissa, where the Banded Krait is found 

In India there is no spitting cobras found luckily

Venom Symptoms and Impact

Snake venom is the cause of many injuries and deaths to humans each year. The affect that snake venom has on the human body varies based on the species of snake and the type and amount of venom that is injected. Each species of snake injects a different venom and knowing the type of snake involved in a snakebite incident can be vital in saving a person’s life.

How does snake venom affect the human body?
Snake venom falls into four categories, Hemotoxic venom, Cytotoxic venom, Proteolytic venom and Neurotoxic venom. Each of these venom types target different systems within the body and cause different symptoms. All of these types of venom will need treatment to deactivate the affects.

Hemotoxic venom attacks and damages red blood cells. This disrupts the body’s ability to clot blood and causes widespread damage to organs and tissue. The most obvious damage is done to the heart and cardiovascular system which pumps the venom around the body. Hemotoxic venom causes intense pain and will eventually result in death if not treated. In some cases the bitten limb is lost or needs to be amputated due to damage caused by the venom. Pit vipers are an example of the snakes that employ this type of venom. Hemotoxic venom does not cause instant onset of symptoms in humans. It may take up to a couple of hours before a human begins to experience nausea, disorientation and headache.

Cytotoxic venom attacks the cells of the body. There are a number of reactions that cells may undergo when injected with cytotixic venom. The cells may begin to suffer necrosis where the cell membranes fail and the cells die quickly. The cells may stop growing and multiplying or they can activate a genetic process in which the cells simply die. The symptoms in humans tend to be extreme swelling at the site of the bite. In extreme cases the area may bleed and blister causing death of the surrounding tissue.

Proteolytic venom causes the molecular structure of the cells in the surrounding area to breakdown. It disintegrates proteins which are the building blocks of cells. Proteolytic venoms break down the muscle tissue in the area surrounding the bite.

Neurotoxic Venom attacks the nervous system and the brain. The venom disrupts the normal function of the nervous system causing the death of neutrons. The most common symptoms in humans include limb weakness or numbness, loss of memory, vision, headache and paralysis.

Did you know?
The venom of proteroglyphous snakes such as the sea snake, mambas, king cobra, red-bellied black snake, tiger snake and death adders usually affect the nervous system. They cause respiratory paralysis and are deadly to humans.

The venom of vipers causes the blood to coagulate and clot in the main artery to the heart. Once bitten the area surrounding the bite swells, becomes discolored and is extremely painful. Within a few hours the victim will begin to vomit. The blood pressure drops and the pulse becomes weak and erratic. If a person survives through these stages including the severe drop in blood pressure they may survive the snake bite. Very toxic vipers require immediate attention or death will occur.

Rear fanged snakes such as boomslangs and vine snakes have venom that destroys blood cells and thins the blood. The early symptoms of a bite from a rear fanged snake include headaches, nausea, diarrhea, lethargy, mental disorientation, bruising and bleeding at the site and from all body openings. Most commonly death is caused by internal bleeding and hemorrhage.

When talking about venomous snakes and other animals with similar stings, there are two main types of venoms these animals use in order to attack its pray or in acts of defense to save itself. One of these venoms acts on the nervous system while the other acts directly on tissues or else on the components of the blood. Due to its effect on the blood components and its function, the latter type of toxin is given the name ‘

Effect of Venom.

hemotoxic venom’ and it is the topic of this article which will discuss its mechanism of action after it enters the body through bite wounds or through any other means.

Description of hemotoxic venom

Although the term hemotoxic suggest that the particular type of toxin only acts on the blood components and its functionality, the same toxin can also act directly on the tissues that lies in its path. Thus, the term hemotoxic venom is a misnomer to a certain extent, although the most notable and the earliest effects of the said toxin may indeed be associated with the blood and its functionality.

Hemolytic effect of hemotoxic venom

When discussing how hemotoxic venom affects various body tissues and blood, destruction of the red blood cells could be highlighted as one of the main mechanisms. Thus, within a few minutes to a few hours of its entry to the blood circulation, the hemotoxic venom can cause ‘hemolysis’ of red blood cells which can eventually lead to a depletion of red blood cells in the circulation. When there aren’t enough red blood cells, the oxygen carrying capacity of the blood would also deplete and many body organs including the brain, heart, liver and the kidneys will suffer as a result. At the same time, the lungs may have to exert an extra effort in order to maintain the oxygen supply, which would manifest as breathlessness and sometimes as chest discomfort due to an overworking heart.

Disseminated intravascular coagulation

Another mechanism that the hemotoxic venom affects within the animal body is the clotting mechanism. A derailment of the clotting mechanism would eventually lead to uncontrollable bleeding within body tissues and to a process known as ‘disseminated intravascular coagulation’ in which the blood clots abruptly within the blood vessels. Such clots can travel to various organs in the body and lead to fatal outcomes such as strokes, pulmonary embolism, heart attack…etc.

Cellular destruction

Although hemotoxic venom is known to act mainly on the blood, it can also act on the tissues that are lying in its path both directly as well as indirectly. However, when a toxin acts directly on the tissues or body cells it is known as ‘cytotoxic’ while it is believed that hemotoxic venom has both properties to a certain extent.

Other characteristics of hemotoxic venom

While these are the main methods in which hemotoxic venom acts on the body, it takes relatively long time before it reaches its full potential compared to other types of venoms such as neurotoxic venom. However, the hemotoxic venom is said to be rather painful as it exerts its actions, although neurotoxins are relatively swift and pain-free in its interference with the nerve activity.

Neroutoxic Venom

The term neurotoxic venom refers to any biogenic molecule that interferes with the normal function of a neuron, sometimes culminating in cell death. The animals most often associated with neurotoxic venom are snakes and spiders. As we shall see, however, many aquatic species also produce neurotoxins, including puffer fish, jellyfish, sea anemones, scorpion fish, cone shells, and octopods. This article will focus on the different mechanisms of action of neurotoxins and briefly discuss the treatments available for people bitten or stung by these creatures.    

Cobra toxin

Cobras are one of the most well known venomous snakes. The neurotoxic component of cobra venom paralyzes skeletal muscles by blocking the nicotinic acetylcholine receptor, much like curare and certain anesthetic drugs. The diaphragm is a skeletal muscle, meaning it contains nicotinic acetylcholine receptors activated in response to acetylcholine released by the phrenic nerves. Death can occur up to several hours after a bite from respiratory muscle paralysis.  

The treatment for a cobra bite is elapid antivenin purified from horse serum. This preparation contains equine antibodies to the toxins present in cobra venom. Since these are not human derived antibodies, however, repeated injections of antivenin will trigger an immunological response called an Arthus reaction or serum sickness. For patients suffering from respiratory muscle paralysis, mechanical ventilation is necessary.

Black widow spiders

After a spider bite, this toxin travels through the bloodstream where it enters cholinergic neurons and causes a massive burst of acetylcholine release. This neurotransmitter causes sustained contraction, or tetany, of respiratory and skeletal muscles followed by paralysis. Tissue necrosis also occurs at the bite site. Treatment consists of airway support (in the form of a mechanical ventilator) along with an injection of antibodies to black widow spider venom.

Puffer fish

In Japan, puffer fish, also known as fugu, is a risky delicacy. Chefs who prepare puffer fish must be specially licensed; still, approximately 50 Japanese die annually after eating puffer fish. The reason is that female puffer fish produce a chemical called tetrodotoxin (TTX) in their ovaries. Some TTX can also be found in the fish's liver and skin. TTX has no distinct taste or odor but acts as a powerful blocker of voltage gated sodium channels, stopping the propagation of action potentials along neuronal axons.

Death occurs over the course of hours due to respiratory paralysis.

Certain species of mussels produce saxitoxin, a chemical with the same mechanism of action as TTX. It is estimated that the poison from a single mussel can kill 50 people.

Blue Ringed Octopus

Found mainly in the Pacific Ocean and Australian coastal waters, the blue ringed octopus produces TTX like the puffer fish. Since there is no specific antidote for TTX, a bite can be fatal in a matter of minutes.     

Jellyfish and sea anemones

These sea creatures contain specialized stinging cells called nematocysts that inject venom in a manner similar to a harpoon. Compared to snake venom, jellyfish venom is less well characterized. From numerous reports, however, scientists know that jellyfish venom can interfere with respiratory muscle function and cardiac conduction. As far as danger to humans goes, the most notorious jellyfish include the box jelly and the Portuguese man-of-war. Anemones are relatively stationary and, unlike jellyfish, present little danger to swimmers or scuba divers.  

Cone shells

These mollusks produce a poison called omega conotoxin, which acts as a powerful calcium channel blocker. Within a few seconds of exposure to this toxin, neurons stop releasing neurotransmitters. The reason is that although the neuronal axons can still conduct action potentials, (mediated by sodium ion influx and potassium ion efflux through voltage gated ion channels), neurotransmitter release requires an influx of calcium ions into the axonal terminal. Once conotoxin reaches the phrenic nerves, they stop releasing acetylcholine; the diaphragm muscle stops contracting; and death from respiratory muscle paralysis occurs a few minutes later. 

A neurotoxin is a substance which inhibits the functions of neurons. Neurons are found throughout the brain and nervous system, and the function of these unique cells is critical for a variety of tasks, ranging from autonomic nervous system jobs like swallowing to higher-level brain function. Neurotoxins can work in a variety of ways, with the danger of exposure varying, depending on the neurotoxin involved and the dosage.

In some cases, neurotoxins simply severely damage neurons so that they cannot function. Others attack the signaling capability of neurons, by blocking releases of various chemicals or interfering with the methods of reception for such transmissions, and sometimes telling neurons to send false signals. A neurotoxin may also destroy neurons altogether.

The body actually generates some neurotoxins; many of the neurotransmitters produced to send messages across the nervous system can be dangerous in high amounts, for example, and sometimes the body produces neurotoxins as it responds to a threat to the immune system. Neurotoxins are also present in large numbers in the natural environment; some venomous animals produce neurotoxins, while heavy metals such as lead are also neurotoxins. Neurotoxins are also used by some governments for crowd control and warfare, in which case they are usually known as nerve agents.

Exposure to neurotoxins can cause dizziness, nausea, loss of motor control, paralysis, difficulty with vision, seizures, and strokes. In extreme cases, the results of exposure may include coma and eventual death as the nervous system shuts down. Especially when a neurotoxin inhibits the function of the autonomic nervous system, the body quickly starts to break down, because a number of important tasks are not being performed.

In the case of acute exposure, someone is exposed suddenly to a dose of a neurotoxin. Asnake bite is an example of acute exposure. Chronic exposure involves slow exposure over time; heavy metals poisoning often takes the form of chronic exposure, with the unwitting victim taking in a small amount each day. The problem with heavy metals is that they build up in the body, rather than being expelled, so at a certain point, the victim will become sick.

A variety of techniques can be used to treat neurotoxin exposure. Many focus on supportive care, performing tasks which the body isn't doing until the patient is stable. In these cases, the patient may recover, but he or she will often experience side-effects related to the exposure later in life. Sometimes, chemicals can be used to block the function of a neurotoxin, or to help flush it from the body. In other cases, there is no cure for exposure, and the goal is to keep the patient comfortable.