On top of a mountain, I surveyed a site for three days in which I saw zero lizards. After 6 hours of no lizards, my brain goes through several changes.
I become convinced that I am bad at spotting animals (and about to be the laughing stock of the team). This time, as I was recovering from a bout of field-season COVID, I managed to convince myself that COVID had evolved the capacity to not only strip away smell and taste, but also pattern-based vision.
I also start seeing “lizards” everywhere. A bit of lichen bobbing in the wind became a lizard dewlapping at me. A strip of peeling pine bark backlit against the sun was the curve of a head pushing away from the tree. A knot, or scar in the bark, looked like a body against the trunk, and a fast moving shadow cast by the wind in the branches looked like the fast scuttle of an anole running.
Even though by the end of the second survey I knew there were no lizards on my plot, I had to keep searching and looking for individuals through each of the surveys. This is important both because I might in fact be able to find a lizard if I look hard enough (and this is what I tell myself) and because it standardizes the search effort. Everyone, no matter how few lizards, must search their plot for a minimum of two hours. If indeed there are no individuals, this then provides valuable information on the habitats that are outside the environmental conditions in which anoles can occur. At these sites above 2000m, anoles must eek out an existence in an environment that is on the edge of their thermal capacity and determining where exactly the boundary at which we stop seeing lizards is incredibly important. Confusingly, our plots about 100m higher up the mountain had plentiful anoles (internal shrug).
Anoles, like other lizards, are ectotherms. In other words, they do not regulate internal body temperatures via physiological processes. Rather, their body temperature reflects that of the environment and they can use behavioral thermoregulation (moving to sit in the sun or the shade) to modulate their body temperature and keep it near their thermal optimum. Anolis armouri, the primary anole at this site—although there also an unknown set of “green ones”—are active thermoregulators and spend much of their time basking in the sunspots on rocks like dragons in an Anne McCaffery novel.
At my plot, with no lizards, my guess was that some set of environmental conditions were too extreme for A. armouri to occur, even though it was only 100m away from plots with individuals. Perhaps since my plot encircled the top of a hill at the head of a valley, it was much more exposed to wind than the other plots, thus being too cold for these anoles. Or maybe the canopy cover was too dense, or maybe there weren’t enough rocks to use for sunning. In other words, I had no idea why my plot didn’t have anoles, just a series of increasingly elaborate guesses as I became more and more desperate to see a lizard. It made for some very anole-poor and imagination-rich surveys.
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