There are few creatures that evoke such violent reactions from people as snakes. Some people are fascinated by them; at lot more are terrified by them. However you feel about them, I hope you’ll at least agree they’re interesting, because they’re what I want to talk about this week.
Here at the Saskatchewan Science Centre we’ve all become highly snake-conscious in the last little while because of the addition of three of these legless reptiles to our little family of living creatures in the Discovery Lab.
One of the snakes, a bull snake, is native to Saskatchewan and is a permanent resident of the Powerhouse of Discovery; the other two, a boa constrictor and an Indian python, are tropical snakes on loan to the Science Centre from Larry Young, a Balgonie high school teacher, who has also loaned us an iguana. All three creatures are an important part of a school workshop currently being offered called Hands-on Habitat.
I’ve had the pleasure (no, really, I mean it!) of handling both of the giant snakes.
Monty (the python, of course) and I made an appearance on a TV talk show together which was memorable not so much for being on TV as for the fact that Monty got out of the canvas bag and the cardboard box holding him on the way to the station, so that I ended up stopped at the side of the road wrestling with a three-metre python in my back seat, while passing motorists did double-takes. Monty won; he rode free of constraint the short remaining distance to the station, where I was finally able to dump him into the bag.
Wrestling with a giant python in the back seat of your car is the kind of experience that makes an impression on you–and when something impresses me, I write about it.
One of the reasons snakes have such bad reputations among humans is that there are some of them who have developed highly effective poison glands and fangs to aid them in hunting and self-defense. This is just one example of the adaptability of snakes, which has served them so well they can live in almost all areas of the earth except for the polar regions and the depths of lakes and oceans. (As any Saskatchewan resident might guess, the garter snake is one of the species of snakes that has adapted best to northern climates.)
Snakes are, of course, reptiles. Fossils indicate that they already existed 180 million years ago, at the time of the dinosaurs. Their ancestors appear to have been lizards who gradually “devolved” their legs. Some snakes, including the boa and python at the Science Centre, still have vestigial pelvic bones and what are called “anal spurs,” the apparent remnants of hind legs.
Without legs, the snake also has naturally developed a unique means of locomotion. By repeated contraction and relaxation of its muscles, it creates a wave-like motion through its body that pushes against the surface beneath it. (If that surface is completely smooth, like glass, the snake won’t go anywhere, though you can bet it will try.)
The snake’s extraordinary body features a number of unusual features, mostly the result of cramming a complete system of organs into a very long and very narrow tube. Paired organs like kidneys lie one in front of the other. Many snakes only have one lung; pythons like Monty have two, but one is much smaller than the other.
Snakes don’t have fur or feathers; instead they’re covered with scales, which are really folds of the snake’s skin. The scales vary in size and shape, depending on where they’re located. Generally, scales on top are small and overlap like shingles; belly scales are large and flat and match up with the snake’s ribs. Where these belly scales (called “plates”) end, the snake’s tail begins. (Yes, snakes do have distinct bodies and tails, just like other animals.)
These scales give snakes their unique feel–and no, that feel isn’t “slimy.” As I can attest, snakes feel quite dry and pleasant. They generally feel cool to us, too, because as reptiles that are what is called “cold-blooded,” which means that their bodies do not generate enough internal heat to keep their temperature at a constant optimum operating level, like ours do.
Various kinds of snakes hunt and kill their prey (all snakes are meat-eaters) in different ways. Snakes that eat unarmed creatures like insects, frogs and fish simply grab them and start swallowing. Other snakes rely on their venomous fangs. Finally, there are the constrictors, snakes that grab their prey, then wrap their coils around it and squeeze it until it expires. The bull snake, the boa and the python are all constrictors. (And again, let me assure you, snakes are extremely muscular creatures. Just try making a big snake do something it doesn’t want to do…)
Snakes swallow their prey whole–quite astonishing, considering the relative size of the creature and the apparent size of the snake’s mouth. Because of a “dislocatable” jaw and other adaptations, a python like Monty is able to swallow prey four or five times as wide as its head. Snakes also have very stretchy stomachs and skin to allow them to hold such big meals.
Because they take in so much nutrition at once, snakes eat quite infrequently. A big snake like Monty can actually go for months without eating, if necessary, and a big meal every three or four weeks is quite adequate.
Obviously, these are just a few interesting (I hope) facts about snakes. You could write whole books about these creatures (and people have), just like you could any of the other fascinating animals that share this planet with us.
For all its undeserved bad reputation, that’s all a snake is, after all–just another animal, another creature ideally suited to its habitat and way of life, full of surprises and wonder and beauty.
Did I say “just” another animal? There’s no “just” about it. Every species is unique, and enriches the world.