54: Common Side Blotched Lizard
I write to you from Arapahoe, Ute, and Cheyenne land. I am interested in learning about the different animals that live in the place where I was born. Before we start with today’s animal, I want to emphasize that biological classification as understood by western society has its roots in racism, sexism, and transphobia – here’s a good explainer about why.
The Common Side Blotched Lizard (Uta stansburiana) is a stout-bodied lizard from the genus Uta, which is species of lizards who mostly live in the deserts of the USA southwest/northern Mexico. The genus name is from Utah, which in turn is named for the Ute people. Like many other lizards from this region, they sit very still and wait for their prey – arthropods – to move into range.
The stansburiana in their name refers to Captain Howard Stansbury, from the US Corps of Topographical Engineers, who first brought the species to European-American attention during his expedition to survey the Great Salt Lake in 1849-1851. Stansbury established the Overland Trail (basically modern I-80 through Wyoming and Utah), which the Transcontinental Railroad would follow a decade later. He also advised Brigham Young to commit genocide against a particular band of Utes and provided material support to that end.
Have you ever played the game rock, paper, scissors? Good news, these lizards have too.
Jeff Mitton, a professor in the Department of Ecology and Evolutionary Biology at the University of Colorado, explains the game:
Males come in three distinct, genetically determined color morphs. The throat and sides can be colored orange, blue or yellow. The colors are not inconsequential adornments — they advertise both the position of the animal in the dominance hierarchy and the male's reproductive strategy.
Barry Sinervo and Curt Lively documented the nexus of interactions among the three color morphs and likened their mating strategies to a game of paper, rock and scissors. In case you have forgotten, two or more players thrust out a hand held flat to represent a sheet of paper, two fingers representing scissors or a fist to represent a rock. Rock breaks scissors, scissors cut paper, paper covers rock. Each is beaten by one and beats one.
Orange males have the highest levels of testosterone, they defend the largest territories, have the largest harems and dominate both blue and yellow males. Orange males mate those in their harems but also invade the adjacent territories defended by blue males to mate with their neighbor's females.
Blue males defend smaller territories with fewer resident females, and although they cannot vanquish orange invaders, they are able to drive yellow males away.
Yellow males are at the bottom of the dominance hierarchy and do not defend territories and therefore do not have resident females to mate. However, they are sneakers, and when orange males are off mating with the harems belonging to blue males, yellow males sneak into the momentarily undefended orange territories to mate the resident females.
The interactions among the three male color morphs cause the morph frequencies to vary over time. When orange males become common, they have few blue neighbors to take advantage of, so orange mating success begins to drop. At this time, the sneaking yellow males have many mating opportunities and high reproductive success, so the frequency of the yellow morph increases.
When yellow males become common, they put relentless pressure on the orange but are not able to mate females on blue territories, for the blue males are vigilant and dominant to yellow. At this time, blue males have a distinct advantage, and their frequency increases.
When blue males are most common, dominant and aggressive orange males raid their harems, so the frequency of blue males declines while the frequency of orange males increases.
This game of paper, rock and scissors in side-blotched lizards causes the male morph frequencies to cycle incessantly through time.