Snakes - Mysterious and Misunderstood
Rock Python
Snakes are elongate, legless, carnivorous reptiles that can be distinguished from legless lizards by their lack of eyelids and external ears.Many species of snakes have skulls with many more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung.
Most species are nonvenomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause painful injury or death to humans. Nonvenomous snakes either swallow prey alive or kill by constriction.
Living snakes are found on every continent except Antarctica and on most islands. They range in size from the tiny, 10 cm-long thread snake to pythons and anacondas of up to 7.6 metres (25 ft) in length. Snakes are thought to have evolved from either burrowing or aquatic lizards during the mid-Cretaceous period, and the earliest known fossils date to around 112 Million years ago.
Russel's Viper
Adding grain to this theory, Some species (Eg. Python) retain a pelvic girdle with a pair of spurs on either side of the cloaca. These Pelvic spurs are the externally visible portion of the vestigial remnants of legs found on each side of the vent in primitive snakes, such as boas and pythons and though not connected to the spine, they are used for clasping and tickling during courtship and mating, as well as combat with other males in some species.
They are are ectothermic or cold-blooded creatures that control body temperatures through external means. In the cold weather, they soak up sunlight. When it is hot they leave their nests in search of cool spots, which could often be within human dwellings or farms.
Certain Snakes have really good vision especially King Cobra and the tree snakes, but most of them are near-sighted like borrowing snakes and the others. Of course, all are colour-blind. They do not have eye-lids to cover their eye.
Snakes can smell pretty well mainly by their sensitive tongue,but not much by their nostrils. The tongue picks up the odours/molecules in the air and the Jacobson's organ above the mouth will make out what the odour is.
Snakes like Pythons & Pit Vipers have heat sensing pits, which helps in detect warm-blooded animals like rodents & birds in absolute darkness.
Snakes in India
Wolf Snake
Snakes are possibly the most misunderstood creature on earth and more so in India. With our amazing diversity in religion and tradition, its no surprise that the snake plays a major fear-factor role in most people's lives.
There are over 270 species of snakes out of which only about 60 are venomous. 4 of those are found in India
Perhaps the most infamous of all venomous snakes are the "Big Four" which are so named because they are responsible for the most human bites in the country. They are:
Spectacled Cobra (Naja naja)
Common Krait (Bungarus caeruleus)
Russel's Viper (Daboia Russeli)
Saw Scaled Viper (Echis Carnatus)
Types of snakes
Terrestrial / arboreal Snakes
These are snakes that live on land or in the trees and are the most common type of snake that come in contact with humans.
Rat snake
Python
Cobras
Vine Snakes
Vine Snake
Water Snakes
Watersnakes spend most of their time in water. They eat frogs, fish and sometimes birds if they can catch them. None of the freshwater snakes in India are venomous, however sea snakes are highly venomous and in some cases more so than even the cobra. Some fresh water snakes have mild venom to help them catch their prey, but it isn't harmful to man.
Olive Keelback
Checkered Keelback
Burrowing Snakes
Burrowing snakes live underground. Of course, there are also other snakes that go underground to escape the heat of the sun and to hide from predators. But burrower’s are the only ones that can dig their own holes. The burrowing snake’s skull is as powerful as the point of a crowbar. Its stocky body and strong neck muscles make it easy for the snake to bulldoze its way through soft soil. There are three groups of burrowing snakes in India:
Small Worm Snakes
Sheildtails
Sand boas
Common Sand Boa
Venom is modified saliva in snakes that is used primarily to aid in immobilizing prey quickly and easily and secondarily as an advanced defense system. Venom is not a single substance, but rather consists of a complex mixture of chemicals called enzymes. Almost all venoms are made up of approximately 90% proteins. Contrary to popular belief and teachings, snakes do not have one type of venom such as a hemotoxin or a neurotoxin, rather, its a combination of different types that causes death.
Snake venom can be broadly classified into two broad categories:
Cytotoxic - Venom that attacks cells.
Neurotoxic - Venom that attacks the nervous system.
Hemotoxin (blood and tissue toxin):
Russel's Viper
Cytotoxic venom functions by breaking down tissues and destroying red blood cells. it can cause excessive scarring and tissue damage and sometimes leads to amputation of the affected area. This cytotoxin combined with hemotoxins are what cause death.
Vipers have a combination of Hemotoxic and Cytotoxic venom.
Cytotoxic venom is sometimes mistakenly referred to as Hemotoxic venom (a sub- category of cytotoxic venom) which only affects the blood and causes no tissue damage.
Hemotoxins destroy red blood cells and cause hemolysis. hemolysis on its own is too slow to cause death and that's where the mixture that makes up the cytotoxins comes in and causes the death of the victim.
Eg. Russel's Vipers, Saw scaled Viper, Malabar Pit Viper
Neurotoxin (nerve toxin):
Spectacled Cobra
Neurotoxic venom attacks the victim's central nervous system and stops the firing of the nerve synapses by blocking the nerve receptors. This can lead to uncontrollable muscle spasms, numbness, breathing difficulties or even total respiratory paralysis.
Cobra venom contains a small part of cytotoxin which is what is responsible for the tissue damage at the area of the bite.
Eg. Cobras, Kraits, Coral snakes.
Snake Bite
Snakebite often results in puncture wounds caused by the animal's fangs and sometimes, envenomation. Most snakes are non-venomous and kill their prey with constriction, however, venomous snakes often bite their prey as a method of hunting and sometimes as a defence mechanism when they are attacked or disturbed.
First Aid in the case of snake bite
According the the World Health Organization (WHO), the recommended procedure for snake bite first aid is the R.I.G.H.T. method.
Reassure the victim
Keep the victim calm. If the victim panics, their heart rate and blood pressure will increase and make the venom spread faster. It may also lead to anaphylactic shock which could kill the victim faster than the venom. Assure the victim that almost 70% of all snakebites are from non-venomous snakes and of the remaining 30%, only half will actually have injected venom, the rest being ‘Dry Bites”. Assure them that they are going to be OK.
Immobilize the affected limb. Do not use compression.
If a bite is on the hand or arm, use a sling (Cloth / strap / towel, etc) to support and keep it from moving. Use a splint in the case of a leg bite and wrap it with cloth / strap etc to keep it immobile. Do not tie the bandages tightly, At least two fingers should pass under the tied bandages. Remember, we only need to immobilize the area and not add too much pressure.
Get the patient to Hospital as fast as safely possible.
TRADITIONAL REMEDIES / DRUGS DON’T WORK. So do not waste time trying to give them to the patient. Keep the patient immobile and calm and rush them to the hospital as soon as possible.
Tell the Doctor any of the following signs appearing on the way to the hospital.
Check for any difficulty in breathing. If the victim stops breathing, give them artificial respiration. In Cobra and Krait bites this may save the victims life.
Check for drooping eyelids.
Check for bleeding gums or any strange bruises / discoloration that may appear.
Check for increases in swelling. Use a pen to mark the limit of the swelling around every ten minutes so that you can estimate the extent.
Check for drowsiness.
Check for any difficulty in speaking or incoherent speech.
Check for any bleeding from the wound that does not seem to stop.
World Health Organisation - Antivenom Database
The World Health Organisation has launched an online snake guide in a bid to overcome anti-venom shortages for poisonous snake bites all over the world. It depicts around 263 venomous snakes by picture from all over the world.
According to them, most anti-venom, when it is available, is often untested or used for the wrong snakebite. This itself can cause serious problems.
The illustrated Internet database is designed to guide the use of anti-venoms and locate possible stocks in the impacted areas, It also helps member of the public to identify the poisonous snakes in their areas.
Database: http://tinyurl.com/WHOsnake
You can filter this for India with the following navigation:
Click on the world map image
Select Asia and Australasia from the 'Region' list
Select South Asia from the 'Sub-region' dropdown list
Click on "India" fom the breadcrumb links on the top of the page.
Snakebite Dont's
Dont cut the wound.
Cutting the snakebite to let blood and venom flow out is a common incorrect misconception and serves no purpose because by the time the cut is made the venom is already mixed with the blood. Apart from the possible risk of infection, Viper bites are an anti-coagulant and hence will not allow blood to cloth. If the victim is cut, there is a possibility that they could die from bleeding to death rather than the venom itself
Dont try to suck the venom out.
Do not attempt to suck out the venom as by the time, the venom is already missed with the blood and won’t do any good. Also, if you have something as small as a mouth ulcer or infected tooth, you risk the possibility of poisoning yourself.
Dont try to capture / harm the snake.
You may endanger yourself and others with you. Stay well out of its way and tend to the victim. Remember, it was only trying to protect itself.
