Colin Donihue

Hi everyone,

Another paper is out! This one was published in PeerJ, my first open access journal so anyone can read the paper here.

The paper is titled “Microgeographic variation in locomotor traits among lizards in a human-built environment.” That’s a long way of saying I looked at lizards living on rock walls and lizards living in more natural (non-wall) settings, and found that lizard leg length was significantly different, lizard sprint speed was different, and most surprisingly, the lizards’ behavior traversing rocks in their path was significantly different.

That behavioral difference is best summarized by these two gifs I made of lizards running down my experimental gauntlet. The first shows a “wall lizard” that had grown up accustomed to running on rock walls. The second shows a non-wall lizard that had almost definitely never encountered this kind of rocky terrain before.

Notice any differences? The wall lizard jumped from stone to stone whereas its non-wall cousin seemed stymied by the rocks, trying to wind its way in between along a more serpentine path. Remarkably, this pattern held very consistently for all of the lizards I measured from sites with rock walls and sites without rock walls.

Part and parcel with this behavioral difference, I found that these wall lizards had longer legs that helped to boost them while making all of these jumps. This leg length difference was particularly pronounced in their feet – the wall lizards had much longer feet which other studies have shown to make all the difference for jumping performance in lizards.

Now the big question, so what? Alright, so lizards living on rock walls seem to look different and run around their habitats differently, but why do we care? Well, this is an example of human-induced changes in traits we know are important to how these lizards fit into their ecosystem. Changes in locomotion could have important effects on what the lizards eat, how well they escape from predators, and how they find and keep mates. Humans are changing landscapes the world over, but it’s looking like some animals, like these little lizards, are capable of changing right along with them. The goal of my research is to figure out how, why, and to what extent this is happening.