Humans are the ultimate predator. If you’re armed with the right tools there’s virtually nothing else that can beat you in a standoff (except maybe antibiotic-resistant bacteria, but let’s forget about that). If you want to befriend the animal, though, it’s a whole different story.
Researchers know that some animals can be sensitive to human behaviours, and lots of past studies have evidenced that certain noises or movements can have an effect on the way an animal responds to a person. One team of scientists at UCLA led by Breanna Putman wanted to know whether color influenced lizard behaviour. Understanding this effect could help scientists and conservationists better predict how animals might react to approaching humans.
Male western fence lizards have blue abdominal and throat patches that they show off to woo mates, much like the males in our own species might, I don’t know, get a tribal tattoo or buy a Porsche to impress potential sexual partners. As it turns out, the lizards seemed to respond best when experimenters wore the western fence lizard’s sexy colour: dark blue.
The team of researchers approached lizards in two sites, one in a busy public park and another in a nature reserve to ensure that they could take general human activity into account. They approached the lizards wearing one of four coloured t-shirts, either dark blue, light blue, grey or red, and measured the distance that the lizards ran. A few days into the study, they also started chasing the lizards around to try and catch them, because sometimes that’s how you do science.
After 15 or so trials in each t-shirt color, the researchers analysed their data and published it in the journal PLoS One. They found that the lizards ran the shortest distances from, and were most likely to be captured by, the researcher wearing the dark blue t-shirt. They ran furthest from, and were least likely to by captured by, the researcher wearing the red t-shirt.
In other words, the lizards’ responses to humans do seem to be impacted by colour. If you’re looking to woo a western fence lizard, maybe just buy a western fence lizard Porsche—that is, a dark blue t-shirt. Keep in mind that this is, of course, just one fairly preliminary study with plenty of room for tweaking and improvement. Would other lizard species also respond to blue, for example, even if blue wasn’t their sexual signaling colour?
One outside expert I spoke to, Lindsey Swierk, a post-doctoral researcher at Yale, thought the study was well-executed and tested something that ecologists think about in the field. “It’s an interesting finding that I think many research groups will likely discuss before planning their next field trips,” she said. “I’d look forward to learning if this pattern applies to other lizard species with differently coloured sexual signals as well.”
For some reason, I can’t stop thinking about a lizard with a mustache in a tank top behind the wheel of a tiny Porsche. [PLoS One]