Environment & Science

Studying lizards? Be sure to wear the right color shirt

A UCLA study with western fence lizards showed that wearing different colors can affect how animals react to humans.
A UCLA study with western fence lizards showed that wearing different colors can affect how animals react to humans.
Peter Stevens/Flickr


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UCLA researcher Breanna Putman noticed something odd when she went out in the hills around Los Angeles looking for lizards to collect for study. She was wearing a bright red t-shirt.

"They would just, you know, take off running, run really high up a tree," she said.

Putman says she figured out that she was scaring the lizards. Animals often see people as predators - and their behavior can be affected by something as simple the color of a t-shirt.

The study Putman authored with scientists from UCLA and the L.A. County Natural History Museum found that the colors humans wear can make lizards more or less likely to run away.

Previous studies had indicated that birds like cardinals or flickers would allow scientists who wore shades of red or orange that matched their feathers to get closer in the field.

Putman wanted to test the same theory on lizards - specifically, the western fence species. 

Male lizards of this species have bright blue markings on the throat and abdomen - and Putman hypothesized she could more easily catch them if she wore a similar color.

The male Western Fence lizard has blue throat and abdomen markings. Researchers say that might be the reason why they're more attracted to blue t-shirts.
The male Western Fence lizard has blue throat and abdomen markings. Researchers say that might be the reason why they're more attracted to blue t-shirts.

She wore different colored t-shirts while hunting for lizards in the Santa Monica mountains. She measured how close she could get to the animals before they ran away. And when they did, Putman followed.

"I’d follow them until they literally went into a hole," she said.

She conducted over 30 trials for four t-shirt colors, noting how easy it was to catch the lizards for each one.

Putman found that the lizards didn't scamper very far away when she wore dark blue.

"They might run a foot away, and then they’d turn around and monitor you," she said. "They’re not running long distances."

Wearing blue also seemed to make it much easier to catch a lizard. Putman caught lizards 84 percent of the time while wearing blue, compared with only 40 percent of the time while wearing red.

Lizards were captured at a much higher rate when Putman wore blue versus other colors.
Lizards were captured at a much higher rate when Putman wore blue versus other colors.
Breanna Putman/UCLA

Putman said this proves that what scientists wear in the field can affect how easily they can observe and study their specimens.

"We suggest that researchers should either just always wear the same clothes when they're out in the field, or randomize the clothing so that there's not just some schematic effect on the results," she said.

But it also trickles down to what everyday people can do while in nature to minimize our effect on wild animals' stress levels, said Putman.

"I think most people realize that if you wear a neon color, it's probably not the best for observing an animal in nature," she said.

There's no hard-and-fast rule - but Putman said if you're dying to see something up-close-and-personal in nature, do your research and color coordinate.

Here's a western fence lizard in action in Southern Oregon last year. 

https://twitter.com/BLMOregon/status/771007854887043073