Wild Lizards Care What You're Wearing

Bad news, pals: Your mom isn't the only one judging your outfit. A recent study published in the journal PLOS One finds that wild animals—in this case, lizards—respond differently to humans depending on the color of their clothes.

It makes perfect sense, if you think about it. Animals rely on their color vision to find food, evade predators, and seduce their mates. From a survival standpoint, color is information, no matter who's wearing it.

Previous studies have found that some bird species with orange or red feathers are less afraid of people wearing orange and red. Would other brightly colored animals have a similar response?

To find out, evolutionary biologist Breanna Putman considered a lizard. The western fence lizard makes its home in the desert climes of the western United States. Both sexes are brown or black, but the males have vibrant blue patches on their bellies and throats, and some have shiny blue spots on their backs. When challenged, males do little push-ups to flex their blue scales and make them look even more impressive. Blue, then, was the color to beat.

Putnam headed out to two lizard hotspots, one at a public park in Los Angeles and another at a nearby nature reserve. The bird studies had only compared people wearing orange and red with people wearing dark gray, which means it's possible that the birds would have responded well to any bright color. So Putnam brought along four t-shirts: one each in dark blue, light blue, bright red, and gray. The dark blue shirt was a pretty close match to the color of the male lizards' macho patches.

For each trial, Putnam put on a shirt, then tried to approach a lizard. At first, she merely walked casually toward them. After a few weeks of this, she switched and began trying to catch them. For every approach, she measured how close the lizard let her get, and how quickly and how far it ran away.

Sure enough, the dark-blue shirt seemed to put the lizards at ease, or at least more at ease than the rest of her wardrobe. While Putnam wore their favorite color, the lizards let her get twice as close (39 inches vs. 78 inches) than they did with other colors. They also didn't try very hard to escape. In red, light blue, or gray, Putnam caught her quarry 40 percent of the time. In dark blue, that number went up to 84 percent.

The findings are a good reminder to all animal researchers, Putnam said in a statement. "What we wear can have indirect effects on animals through changes in their behavior."