"First they are cowards. Next they are bluffers. Then they are warriors."

...So say people who truly understand snakes, according to Whit Gibbons, herpetologist with the University of Georgia's Savannah River Herpetology Laboratory. Like many herpetologists, Gibbons thinks serpents aren't the bad guys we've made them out to be, ever since Eve ate that apple. Really, say the experts, snakes are just misunderstood.





At the same time, it's easy to see why snakes have become humans' most potent symbol of evil. They're legless, slithery, scaly creatures. They have scary-looking fangs. Some can lift up a third of their bodies' and spread dark hoods. Their eyes are glassy and unblinking and their long forked tongues flick forward. They strike quickly and their bites can be so venomous as to dissolve your skin on the spot.

They leap from trees, winding their bodies around prey and squeezing it to death. They open their mouths and stretch their jaws around much larger animals, swallowing them whole. They are the image of an unreasoning, implacable, inescapable, and very efficient killer. In much of Asia, people kill them on sight.


You'd slither too if you had no limbs! (Photo David Scott)

But take a real, hard look at the snake and a different image emerges. Feature-by-feature, the snake is an amazing collection of specially evolved traits that give it graceful movement, unusual sensory apparatus and the ability to hunt for food and defend itself against the odds.

That creepy crawly feeling

People can be creeped out by a snake's slithering, but it should really be looked at as a very efficient form of locomotion that evolved in animals confronted with unique movement problems. Scientists say snakes have been around since the time of the dinosaurs, over 100 million years ago. Their evolution - and success -- as a long limbless land or water animal has several possible explanations, says George Zug, curator of amphibians and reptiles for the Smithsonian Institution's American Museum of Natural History.

"There are three scenarios proposed by scientists," Zug says. "One, they came from aquatic animals: the very large marine lizards in the Cretaceous [146 to 65 million years ago], that were called mososaurs. Two, the snakes' ancestors may have been fossorial - burrowing animals. Three, snakes may have arisen in a grassy environment, where it was more effective to undulate than crawl."

That undulating requires a special skeletal and muscular design. Snake vertebrae are numerous and connected by strong joints. Up to 20 sets of muscles on each side move these vertebrae, ribs and skin. Lateral (sideways) undulation, used by most species, occurs when contractions on opposite sides of the body create waves, so that the snake moves forward as it pushes against the ground, water or whatever it's on. But some species, like heavy-bodied pythons that want to stalk their prey slowly, move by symmetrical contractions that inch along the skin of the belly. Sidewinding is accomplished by having two parts of the body momentarily touch the surface, while the rest of the body accelerates.


Of course snakes don't close their eyes -- they can't. (Photo National Aquarium in Baltimore)

Now snakes have the ability as nineteenth century scientist Sir Richard Owen put it, to outswim a fish and outclimb a monkey. And there are many specialized forms. Rosy Boas have strong trunk muscles that allow them to crawl vertical rock faces. Sidewinders move sideways across desert sand dunes. Black mambas may reach speeds of between 10 and 16 kilometres per hour.

Those eyes and that tongue

Snakes' eyes are unblinking - but only because they have clear scales that cover and protect them. And while they may be ever-open, they're not really staring you down. In Snakes: The Evolution of Mystery in Nature, Cornell herpetology professor Harry Greene notes that snakes largely sacrificed visual and airborne sound cues for more chemical and tactile sensing. In fact, eyes may be reduced or even absent, as in blindsnakes.

As for that flickering tongue - well, if you see it come out, you know that the snake is just trying to get to know you. Capturing odour molecules, the tongue transmits them to its Jacobson's organ, which allows the snake to sense whether prey, predator or mate is in the vicinity.


At heart, snakes are bluffers, like this Eastern Hognose playing dead. (Photo David Scott)

Hissing, rattling and that towering hooded menace

Snakes can definitely look and sound scary when they want to. But that's essentially what they're trying to do - look and sound scary. Hissing sounds, and the rattlesnakes' rattles, are aimed at warning away potential predators. And the cobra's hood, the spreading of the ribs in the neck that gives the snake its menacing appearance is really just a trick to make you think twice about getting any closer.

"Lots of snakes do this to look larger, more threatening," says Whit Gibbons of the "hooding" phenomenon. "Even non-venomous snakes, like the Hognose snake - it acts just like a cobra, but doesn't bite."

Reactive, not aggressive

Some snakes had to develop venom and the ability to constrict in order to catch prey without limbs, without suffering injury. But humans are not prey for snakes. Once you understand that snakes really would rather not bite you or try to constrict you, you should also know that if they do so, it could be lethal. But don't begrudge them - it really is their only option.


As for the use of venom or constriction against a potential predator - like humans - the experts agree that the snakes are simply acting to protect themselves. Folklore that has snakes stalking humans, the scientists say, are just a big misunderstanding.

"I do not think any snakes are aggressive, but many are defensive," says Whit Gibbons. "If you give snakes the chance to get away, they'll do it. If it comes after you, it's because it feels threatened."

How can it feel threatened if it's following you? George Zug explains that "you may not know what you do."

"Usually people have boxed the snake in, and it feels there is no way out," Zug says. "And individual species - and individual snakes - can be either more docile or more likely to bite. Certain species are more nervous, like mambas and Taipans, or King Cobras defending their nests. Then they are labeled aggressive. But if that's aggressive..."

So what to do if you are faced with a staring, hissing or rattling or hooded snake? Scientists say the best thing to do is probably to stay very still, allowing the snake to slither away. However Wolfgang Wuster, snake research fellow at the University Wales has an added warning for those travelling in cobra territory.

"In Southeast Asia, where spitting cobras are found, it is a good idea to shield one's eyes if the cobra is confronted at close quarters (less than three metres), and if the snake rears up and faces you," he advises.