Sometimes I just kick myself for being stupid. At Why Evolution is True, Jerry Coyne does a post on one of the most remarkable of animals, and of developed forms of locomotion: the Paradise Tree Snake, the only snake that flies.
Now, this wasn’t news to me, since I’d seen a brief mention in a book years ago, but then, before I started blogging, found videos of the research that was being done. I saved one (Fast Video Download plugin for Firefox – if you’re not using it you’re a peepants) and come across it from time to time in my folder, but for some stupid, stupid reason never decided to do a post on it. So Jerry once again beats me to the punch, and includes some nice details on the manner in which they launch and glide. Go read it, even if you don’t like snakes – this is one of the coolest things you’ve ever seen..
Pay close attention to that video clip. In the slow-motion sequences where the snake can be seen undulating in the air, look at the background. Notice the lateral blur – this little bugger isn’t simply controlling its descent, but maintaining a remarkable glide ratio for forward, directed movement. I’m sure you know about flying squirrels and sugar gliders, and perhaps even heard about the Draco genus of flying lizards, and if you’re really into your cool animals you know of the various flying frogs. None of these truly “fly,” in the sense of propelling themselves through the air like birds, bats, or insects, but all of them perform glides in much better ratios (that is, lateral movement compared to descent) than simply controlling their fall for a soft landing. The snake earns props for the coolest of them all simply because it possesses no special body structure to catch the air, but simply works with what it’s got. Many snakes can flatten their bodies for certain purposes, like cobras and hognose snakes, so this is just an extension of this talent.
One thing I wish they’d stop putting in videos like this is unnecessary sound-effects. You’ll notice that the monitor appears to make gulping, hissing noises every time it appears, something that it almost certainly does not engage in routinely, and possibly doesn’t even do at all. The ridiculous habit of having to add “appropriate” sound effects for every animal shown is something that directors need to break themselves of. For instance, having handled hundreds of snakes of all sizes since I was eight, I can tell you I’ve heard a snake hiss only four or five times – you wouldn’t suspect that from the times you’ve heard it on TV and movies, would you? Also note that the descending scream you may associate with eagles, heard every goddamn time one appears on screen (and often when they don’t) is not an eagle’s call at all, but a Red-tailed Hawk’s. Bald Eagles sound like overgrown canaries, not terribly majestic.
This video shows the mechanics of flight a little bit better, especially the launching, and also allows you to see how small these snakes really are – they rival in size the Rough Green Snake found here in North Carolina, a pencil-thin shoelace of a reptile occasionally seen in the header image at top. It’s a shame the translation of the researcher into the native language of the source drowns out the English he’s actually speaking.
One more item to remark on. You’ll note the difference in style between the video Coyne features and the one above. Coyne’s is more dramatic, an apparent slice of the snake’s life, but as I’ve posted about twice before, this video is certainly staged (no fault of Coyne’s, of course.) Operating high in a jungle canopy where both of those species can be found is exceptionally difficult, and having enough cameras in position to capture all angles of the drama would be remarkably fortuitous. Note the director’s popular focus-shift redirection of attention from the threatening monitor in the background to the snake in the foreground – yeah, that’s something that you’ll capture naturally, with good framing and good lighting and an appropriate lens to allow such a shift. Uh huh.