There are roughly 3,700 recognized snake species inhabiting temperate regions on every continent except Antarctica until the sequel of Snakes on a Plane crashes at McMurdo Station. Vacation planning note: there are no snakes in Ireland, Greenland, Iceland, or New Zealand. Approximately 600 species are venomous of which an estimated 200 or 6% pose a threat to humans. Snakes are classified under class Reptilia, order Squamata (scaled reptiles), suborder Serpentes from Latin serpō meaning “to crawl or creep.” All snakes are predators and many have specialized diets consisting of small mammals, fish, amphibians, invertebrates, and other snakes and reptiles.
Snakes have specialized body structures including teeth for envenomating prey; flexible skull bones with elastic ligaments for consuming prey larger than their head; specialized digestive enzymes to break down bones, feathers, and hair; absence of external ear openings (instead they “listen” to vibrations through the ground using their entire body); and advanced sense of smell using the Jacobson’s organ which is why snakes flick their forked tongue then bring it back into their mouth to touch the Jacobson’s organ. Some snakes have specialized scales to improve climbing or allow rattling, while others have infrared-sensing pits to locate warm-blooded prey.
Snakes serve an important ecological role by serving as both predator and prey. They help keep rodent populations in check and serve as a valuable food source for mammals, raptors, egrets and other daring critters. Venom has proved to be of great economic and medical importance as complex protein concoctions evolved over millions of years into specialize and sophisticated mechanisms that target organs, tissues, and cells. They have helped researchers develop new medicines and treatments for a range of diseases and many new trials are underway. Captopril® is an ACE inhibitor used to treat high blood pressure and heart failure that was developed from the venom of the Brazilian viper (Bothrops jararacussu). It was the first FDA-approved drug (1975) developed from venom. Integrilin®, an anti-clotting agent for the treatment of coronary syndromes, was derived from the venom of the dusky pygmy rattlesnake (Sistrurus miliarius barbouri) native to Louisiana and Florida. Aggrastat® was derived from the saw-scaled viper (Echis carinatus) from India also for its anti-clotting properties to treat coronary syndromes.