All snakes are predatory, and there are no known examples of vegetarians among them. Worms, insects, spiders, fish, amphibians, birds, mammals, and other reptiles are among the usual fare, although some snakes have developed specialized tastes for exclusive diets of snails, bird eggs, and certain insects.
Although smaller and weaker prey can be swallowed without great difficulty, larger and more active animals need to be subdued. Snakes use two methods to do so: constriction and venom.
Venomous Snakes Have Fangs
Venomous snakes have special venom glands and specialized teeth called fangs for delivering the venom into their victims. In some venomous types, such as the cobras, mambas, and coral snakes, the fangs are short, fixed, and erect at all times. In rattlesnakes and others of its kind, called vipers, the fangs are longer and fold back when the mouth is closed.
Most venomous snakes have their fangs in the front of the mouth, but in the back-fanged or rear-fanged snakes, the fangs are to the back of the mouth.
The Effects of Venom
The terms venom and poison are often used interchangeably and considered by many to be synonymous; they are not. Poisons can be absorbed through the skin or digestive system while venom must be injected into the tissues or blood stream through some mechanical means. Thus, it is possible to drink snake venom with no ill effects as long as there are no lacerations inside the mouth or digestive tract. (Do not, as they say, try this at home.)
The clear to amber venom of venomous snakes can be grouped into a limited number of categories according to its effects: (1) substances that cause the disintegration of tissues, (2) anticoagulants that destroy the clotting capacity of the victim’s blood resulting in heavy bleeding (hemotoxins), and (3) neurotoxins that act on the nervous system, especially the nerves of the respiratory system and heart.
Venom is an effective offensive weapon for securing prey and can also play a defensive role in deterring enemies. The most lethal land snake venoms are found in two Australian snakes, the inland taipan (Oxyuranus microlepidotus) and the king brown snake (Pseudechis australis). The poisons of these two species are fatal to a 20 gr (0.7 ounce) mouse at a dosage of 1 microgram (1 millionth of a gram with a gram being the amount of salt one can pinch between the thumb and forefinger).
One bite of an inland taipan carries enough venom to kill 100 people (or 250,000 mice)!
The Types of Venomous Snakes
Venomous snakes are generally classified in three taxonomic families based in part on type of fangs:
- Elapidae – cobras, kraits, mambas, sea snakes, and coral snakes with short, permanent erect fangs in the front of the mouth.
- Viperidae – vipers, rattlesnakes, copperheads, cottonmouths, adders, and bushmasters with highly developed, movable, tubular fangs at the front of the mouth.
- Colubridae – boomslangs, tree and vine snakes, and many others, though not all colubrids are venomous. This very large family is not a natural group and has classically served as a dumping ground for snakes that don’t fit neatly anywhere else. The venomous members of this group have short permanently erect fangs in the rear of the mouth.
Only four types of venomous snakes are found in North America – 2 genera (Micrurus and Micruoides) and three species of coral snake, copperheads (Agkistrodon contortrix), cottonmouths (Agkistrodon piscivorus), and two genera (Crotalus and Sistrurus) containing more than a dozen different species of rattlesnakes.
First Aid for Snakebite
If someone is bitten by a venomous snake, call for emergency assistance immediately. Quick medical response in such a situation is critical for survival of the victim. Until emergency assistance arrives, the American Red Cross recommends the following:
- Wash the bite area with soap and water.
- Immobilize the bite area and keep it lower than the heart.
- Cover the bite area with a clean, moist dressing to minimize swelling and discomfort.
- Closely monitor vital signs such as pulse and breathing rate.
If the victim is unable to reach medical care within 30 minutes, additional measures must be taken:
- Apply a bandage, wrapped two to four inches above the bite, to help slow the venom. This should not cut off the flow of blood from a vein or artery - the band should be loose enough to slip a finger under it. Do NOT apply a tourniquet for this purpose.
- A suction device can be placed over the bite to help draw venom out of the wound without making cuts. These devices are often included in commercial snake bite kits.
“You know, you can touch a stick of dynamite, but if you touch a venomous snake it'll turn around and bite you and kill you so fast it's not even funny.” (Steve Irwin)
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