Lizard Game

Side-blotched lizard - Blue phase. Inktense pencils, pen-and-ink and gouache

Side-blotched lizards are pretty common in The Southwest. So it was especially interesting to hear about the Game of Rock-Paper-Scissors that a lot of their populations play.

The Side-blotched Lizard males come in three color phases: Orange-throated, Blue-throated, and Yellow-throated.  These color phases have different behaviors and mating strategies.

The Orange males are big, flashy and aggressive. They guard big territories containing several females.

Blue males are smaller, less aggressive and guard smaller territories, usually just containing one female.

Yellow males have more or less given up on the whole ‘maintaining a territory’ thing. Instead, they try to get into other lizard’s territories unnoticed. Their yellow color means they look more like female lizards, so they are able to sneak in and mate with the females guarded by the other, territorial, males.

Orange, hyper-territorial males have an advantage over the Blue, single territory, males because of the Orange males’ size and aggressiveness. So if a population is dominated by Blue, single territory, males, Oranges will tend to ‘win’ and become more numerous.

Since the Oranges have a lot of territory to guard, they can’t pay as much attention to each female in their territory…giving the sneaky, female-looking Yellow lizards an advantage. If a population of lizards has lots of the big, aggressive Orange lizards - the sneaky Yellow lizards increase.

But the Blue, single-territory, lizards do better when there are a lot of the sneaky, Yellow lizards.

So over the course of years, at least some populations of Side-blotched lizards cycle  in the relative proportions of Orange, Blue and Yellow lizards. Orange (big territories) beats Blue (small territories), Yellow (sneaky, no territory) beats Orange, and Blue (small territory) beats Yellow (sneaky, no territory).

So…Rock-Paper-Scissors. Pretty neat. Makes one wonder how many other games like this go on in the world, maybe games that don’t have nice physical signifiers like throat color.