Types of Snake Venom


Out of the 2900 known snake species in the world (2007 figures), only 450 are venomous, making it just about 15.50 percent of their entire population. Out of the 7000-8000 Americans that are annually reported with snakebites, less than 15 die of the toxic poison. However, most people still panic on seeing a snake and try to kill it. Just like a dangerous person, for instance, a terrorist or murderer, cannot be identified by mere looks, neither can a venomous snake. Both of these are more of a threat to America, and indeed the world, than snakes ever were. Most snakes are not venomous, and even from those that are, only about 250 are capable of killing humans.

Snakes are dangerous because of their venom. Venom is essentially highly-modified saliva that is made up of 90 percent proteins and 20 percent enzymes. Most of these enzymes are harmless to humans and are generally not dangerous when ingested. Hence, technically, it is not really poison. There are about 20 toxic enzymes known to man, and unique mixtures of these zootoxins and proteins make for the lethal weapons of snakes. The venom contains phosphodiesterases (attacks the cardiac system), cholinesterase (loss of muscle control), hyaluronidase (increased tissue permeability), ATPases (disrupts energy fuel use), and various amino acid oxidates and proteases. It is stored in a large sac-like structure known as the aveoli and injected through a set of tubular fangs.

Snake venom can be broadly categorized into many types, but the most unique and interesting four are described below.

Hemotoxic Venom
This attacks the cardiovascular system, circulatory system, and muscle tissues, thus directly leading to heart failure. The crotalus atrox, notoriously known as the western diamondback rattlesnake, uses this deadly venom to make its prey more pliable. This venom leads to blood poisoning and affects the blood clotting mechanism to such a grave extent that the victim can die of internal bleeding. Usually, no pain nor any other symptoms can be observed for almost 1 – 3 hours (sometimes even 8). This makes it deadlier, as the victim is usually beyond medical help by the time the cause is even ascertained. The symptoms are lethargy, headaches, nausea, vomiting, etc. Some of the scariest symptoms of a snakebite of this kind are bruising or blood spots beneath the victim’s skin. In worst cases, blood is known to ooze out from all possible bodily openings. It is these venoms that usually cause excessive (and hideous) scarring, gangrene, and permanent or temporary loss of motor skills. It can even result in the amputation of the affected limb.

Neurotoxic Venom
This goes after the central nervous system and brain. It often results in respiratory paralysis and heart failures. Its effect can range between mild seizures to death. Cobras, mambas, sea snakes, kraits, and coral snakes are known to possess it. King cobras (ophiophagus hannah) are the most infamous carriers of this venom. This venom is essentially nerve destroying. Hence, one can see speech and swallowing difficulties, drooling, difficulty in breathing, respiratory arrests, convulsions, and sometimes even prolonged unconsciousness in the victims. The milder symptoms are dizziness, tunnel vision, blurred vision, and increased sweating. It causes a very fast degeneration of the synaptic nerves, and this is the reason for the blockage of nerve impulses sent to and from the brain to the muscles.

Cytotoxic Venom
This is a milder form that generally causes only localized symptoms (at the location of the bite). It is a cell destroying poison that eradicates everything in its path – blood vessels, cells, and tissues. The symptoms of the invasion of this venom are generally seen around 10-15 minutes after the bite. The symptoms are generally a localized pain accompanied by severe swelling and bleeding. One can easily spot the formation of red blisters near the bite area. This venom causes blue/black spotting due to limited blood circulation. The body often revolts against the invasion of this venom by causing nausea and vomiting. If not treated within four hours, it generally needs an amputation. Puff adders (bitis arietans) usually contain this venom.

Myotoxic Venom
This venom is found in the bothrops moojeni, commonly known as the Brazilian lancehead snake. It is known to cause muscular necrosis. Its symptoms are a thickened-tongue sensation, dry throat, thirst, muscular spasms, and convulsions. It also causes a stiffness of the jaw, neck, trunk, and limbs, along with severe pain in movement. The symptoms often start with drooping eyelids and then turn to more austere results like loss of breath and blackish brown urine discharge. This venom contains peptides that destroy the muscle fiber proteins and result in myonecrosis (muscle destruction). In the very later stages (when treatment is delayed), the muscle proteins enter the blood stream. The kidney overworks in trying to filter out this junk and often gives up trying. Kidney failure is the reason for the dark coloration of urine.

Snake venom is not dangerous if medical treatment is speedily provided. Where it is not possible to get medical aid quickly, it is always advisable to be aware of the first aid measures. Some important things to remember are, never make any incisions in the bite area and never try to suck out the venom orally, as these methods can do more harm than good. Also, immediately call a doctor. You can also speak to your doctor and inquire about keeping an anti snake venom at home as a precaution if you live in an area where venomous snakes are common.

Some far out places in South Africa ensure that first aid in case of snakebites is a subject tackled in schools. They know that there are many killer snakes in South Africa. These animal-loving people have devised a way to live with the snakes, by simply being aware and taking care. They try to live in harmony, where no man kills the snake and the snakes return the favor. No wonder then, that Africa is a part of the few remaining wildlife havens.