A Week in the Life of U131

When you’re collecting data on the behaviour of individual animals over time, as I am this summer, your observations sometimes feel less like a collection of numbers and more like a collection of personal narratives. Of course, the data are both numbers and narratives, and when it comes time to analyze this collection of datapoints and understand the patterns that emerge from it, the numbers will be all that matter. But in the meanwhile, before I can look the bigger picture, I enjoy considering the individual narratives. And this week, I encountered a lizard whose story illustrates why it’s worth considering these narratives at all.

I first saw U131 last Wednesday, a full two weeks into sampling at my current fieldsite on the University of Florida campus. He appeared on a perch near the edge of the park, which borders a patch of forest. I’m not sure how far he travelled to get to this perch, but within the next day he had travelled a further fifteen metres to arrive at the weirdest section of my fieldsite.

These two logs and three tree trunks have housed at least fifteen different lizards over the last three weeks, including some of the largest males in the site. Why is this weird? It’s weird because the males in this area have shown no sign of excluding one another from the space around them—in other words, they aren’t being territorial. Still, I was skeptical that this already-crowded area could sustain yet another lizard. After all, lizards aren’t supposed to live in the reptilian equivalent of hippie communes.

But U131 seemed determined to grab a spot here. On Thursday, I spotted him locked in fierce battle with U36, a longtime resident of the logs. U36 has the red beads sewn into his tail, while the blur of yellow and black are the beads on U131’s tail.

An hour later, they were still fighting, and it looked like U131 was getting the worse of it.

The fight could have gone either way. While U131 is bigger than U36, which is almost always an advantage in an anole fight, U36 had the advantage of fighting on his home turf. I wasn’t too surprised when I saw, the next day, that U131 had wandered onward to a tree over 30 metres away.

But the logs must hold some allure, because by this afternoon, U131 had made the long journey back, and was busy displaying at another one of the area’s residents.

We’ll see, over the coming months, whether U131 hangs on at the logs or moves elsewhere in the site to encounter and interact with other lizards. By the end of the season, U131 will be just one datapoint among hundreds, an example of a large male who didn’t maintain a territory across the whole breeding season. We’ll know by then if his behaviour is the exception or the norm.

But for now, U131 exemplifies the importance of the individual example. While the aggregate of all the lizards we observe will show us what does happen, a single lizard shows us what can happen. We now know, thanks to just a week of watching U131, that large male brown anoles sometimes move among perches many metres from each other, wandering in a way that we do not expect from territorial lizards. Whether signal or noise, U131’s narrative expands what we know is possible in the world of the brown anole.