Friday, 4 February 2011

Can a snake climb a wall?

Do you think a snake can climb a wall? Even a vertical corrugated iron wall?

Well, this morning I was enjoying a cup of tea and reading the news when I heard one of our tree frogs give a quiet croak. Nothing unusual there, they croak like that if they think it might rain, or if they hear something that sounds like distant thunder.

Then it croaked again, a little louder, and sort of "insistent". Still nothing unusual - the day was heating up, and the frog sounded like it was on the outside of the wall of the house somewhere, so it was probably getting quite warm. And that sort of plaintive distress call is their way of saying, "Don't like this, but there aren't any options I can think of".

A bit later it croaked again, louder and more distressed. Hmmm.... not so good, but probably just the heat. Again, louder, more distressed, then another call and another. Frog in trouble. More precisely, frog being attacked by a snake. We hear it regularly here, and if we are quick enough we can save the frog from being eaten. Not that we want to deprive the snake of its meals, but they get plent of frogs when we can't hear, or when they are on the roof and there is nothing we can do about it. and anyway, the stupid snakes often try to eat the fully grown tree frogs, and that they can't do, so the frog just gets carved up by the snake's fangs, not to mention terribly agitated.

So I rushed out to see what was going on. I went along the side of the house, looking on the ground, because I really didn't expect to see the snake up the wall of the house, and I've never seen one up in the rafters under the eaves - just doesn't seem possible for them to get there. So there I was, walking along the gravel beside the wall, looking into the longish grass near my feet, trying to see frog or snake. Suddenly, a movement out of the corner or my eye, in fact right at eye height, on the wall of the house! I jumped back, turning as I did so. There was the snake above me, flat against the vertical wall, beside the window, with its head pushing into the gutter where the wall meets the top of the window. Clearly there was a frog in there.

When it realised how close I was the snake started trying to climb the wall. Here's what it looked like.
Using the corrugations in the wall as a measure, that snake is at least 1.3 metres long, and probably 1.5 metres.  Except where it is supporting the top part of its body on the top of the window, it is held on the wall only by the bits of its tail jammed between the iron and the window frame and any friction from its scales on the corrugations.  And in fact when I first saw it, that was all that it had to hold itself in place - none of it was resting on the top of the window at that stage.

The lowest part of its tail is 1.6 metres off the ground, so it had to get up there the same way, jamming curves in its body into the space between the corrugation and the window frame.  Sort of like a rock climber doing finger jams to hold themselves on a vertical face with their fingers in a crack and the friction of their feet pressed against the rock face.

It's been quite a time for reptiles, particularly these tree snakes.  Our neighbour John and I were sitting having a cup of tea outside the office a week ago, and a tree snake (mabye this one) went past us and climbed into the carob tree by the bird bath.  Two days later I was watching TV in the evening when I became aware of something watching me.  A green tree snake was resting its head on the top of the TV, staring at me.  Silly me tried to shoo it outside with a broom but of course that panicked it and it slithered off to find a hiding place, so I had to finish my TV viewing knowing that the snake was still somewhere close by.

About ten days before that I nearly stepped on a big green tree snake, possibly as long as the one on the wall today, on the track down near the creek crossing.  That one got as much of a fright as I did, and reared up to threaten me - they are full of bluff, but it is very unusual for them to try to strike - and anyway they are harmless.  Here's the photo I got of that one.  You can see the blue skin starting to show between the scales. When they are really threatened they inflate their bodies much further so that there is a large area of this iridescent blue sking showing - quite confronting.
The other recent reptile experience that comes to mind is the Water Dragon that was watching me pull out weeds down by the creek crossing when the creek was running strongly in January.  We see very few of these here - maybe becasue there isn't usually any water in the creeks - but they are beautiful animals, and this one was in full colour.

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