It’s been a couple of weeks now since I got these shots, having set them aside for a writeup, and I’m finally getting to it now. Don’t judge. Or judge all you want, because I’m not paying attention anyway.
While alongside the creek that forms the east edge of the property, I noticed a large yellow-bellied slider (Trachemys scripta scripta) drifting in the water, and notably, not diving at my approach. I took the opportunity to fire off a few frames of course.
Despite the fact that it was turned in my direction and I was creeping closer, unable to do so silently with all the ground clutter, the turtle remained resolutely in place. I passed the point where it should have been completely aware of my presence, and still it remained, floating placidly. This was too suspicious, and I made it a point to examine the photos closely once I had unloaded the card. Here’s a closer crop of this same frame:
Yep, the turtle was at least sight-impaired on that side, but likely completely blind there – I can’t vouch for the other side because it never turned that way.
Curiously, the blind spot on half of its field of view did not prompt the turtle to try and compensate by turning its head; it apparently lacked the reasoning ability to piece this together. Moreover, the noise of my approach, coming quite close, was also not enough to spark its flight response, even though I would have thought they’d at least work together. So while it appeared suspicious of the noise and was indeed oriented towards it, because it did not see any danger, it was not convinced that danger was actually present.
There are plenty of turtles in our pond, and there’s no question that they’re sight-oriented: we don’t have to be very close at all before they abandon their basking spots for the safety of the water. I would have though that their hearing was a significant factor in this too, but now that I’m thinking about it, it doesn’t seem to be – it only tells them where to look for danger. Yet, they also have very specific things that they’re watching for too, since I’ve observed them basking on logs as the ducks passed within a meter and not caring in the slightest. Today I had the kayak out on the pond for the first time (properly, anyway,) and while the sliders all abandoned their basking spots, one little turtle on a small branch allowed the kayak to get within two meters before it decided that this might be a hazard and went for the water. Whether this was because it was also unable to see the kayak, I cannot say, because I wasn’t close enough to see it in detail, but I’ve previously approached a turtle from the water level (snorkeling) and it was quite unconcerned until I got very close, so perhaps it also depends on circumstances? Water residents = probably okay? I’ll have to do more observations.