This week, we have a little curiosity: an eastern garter snake (Thamnophis sirtalis sirtalis) providing a threat display of flattened head and inflated body, attempting to look big and dangerous. First off, very few snakes ever engage in such displays – everybody knows cobras, of course, but they have a much more distinctive shape when displaying (and none at all when they’re not.) And the two species of hognose snake are known for it… except when they don’t bother. But this image, from 2013, marks the only time I’ve ever seen a garter snake do it.
In a way, this doesn’t seem too remarkable, since I’ve seen ridiculously few garter snakes at all in North Carolina, and the last time one was featured on the blog (as well as the first time,) was 10 years and three days ago. However, they were by far the most common snake to be found in Central New York when I was growing up, and I’ve handled literally hundreds of them – all sizes, all dispositions, all times of the day. Only one was particularly aggressive, biting me several times as I scooped it out of a ditch, and I put this down to it having survived a recent encounter of some kind. For the most part, garter snakes are pretty mellow, and typically defecate on anyone that picks them up as their main defensive mechanism, besides wriggling madly. There was a natural gas junction box on the corner of our property, which had some gaps in the mortar of the concrete footer, and the garter snakes simply adored this haven; one summer day, sprawled across the top of it where I could see the gap, I captured twelve snakes exiting the box.
Yet the one pictured here was encountered at the Eno River, at the edge of the parking lot, and it was about as quiet as possible in any such setting. I had been waiting to meet with a student and was strolling along the edge of the parking area, so I knew no person had been near for several minutes at the very least, no visible or audible commotion, and no large birds. I approached quietly and not particularly close – there was no danger that I was about to step on it. What, exactly, caused this one to produce this rare display remains beyond me.
After meeting with then student, by the way, I did a little more poking around and captured another snake encounter, much more dramatic.
I’ll point out something while we’re here. The lightest markings along the body, very very pale blue, are not markings at all but the complete lack thereof; those are actually gaps between the scales where the underlying skin is showing through, indicating how much the snake is swollen, Most times you can only see this as the snake is swallowing something sizable, stretching out beyond normal proportions. But it adds a bit of contrasting color to the pattern, and maybe that was the point: it was showing off for the camera. Ya never know…