Color of Your Clothing and How It Affects Animal Behavior

If you love nature, wildlife-watching is probably one of your greatest joys. And because you care about animal welfare, you most likely try to ensure that your observations don’t interfere or disturb the creatures you like to view. That’s why conservancies and preserves, such as our national parks, have guidelines that state that visitors should stay at least 300 feet away from predators, such as bears and wolves, and 75 feet away from bison, elk and other animals. Other good tips include backing away when an animal looks distressed; no close encounter or photo is worth risking an animal’s life because it can’t go about its business due to our presence.

But have you ever considered the color of your clothing (barring camouflage gear) when seeking out wildlife? It turns out that there are other, subtle ways that we impact wildlife when we’re in close proximity.

A recent study in Costa Rica bears this out, but it’s not the only one that shows that what we wear when we visit the worlds of animals makes a difference.

Orange, blue and green

To determine how your choice of clothing could affect the behavioral habits of the wildlife around you, a team of researchers—including faculty at the State University of New York at Binghamton; California State University, San Bernardino; and Iowa State University—traveled to Costa Rica to conduct an experiment on water anoles (Anolis aquaticus), a variety of lizard. At the Las Cruces Biological Station, these particular lizards are restricted to a fairly small range, ensuring that these populations haven’t seen many humans in their lifetimes and aren’t biased by any previous human interactions.

The goal was to see how ecotourists could unintentionally have an effect on wildlife native to the area. To collect the data, the scientists visited three different river locations wearing one of three different colored shirts:

1) orange, because male water anoles have large orange dewlaps (an extensible flap of skin on the throat), which is their most conspicuous sexual signal;

2) blue, chosen as a contrast, since the water anole’s body lacks the color blue;

3) green, to match the tropical forest environment of the testing site in Costa Rica.

Based on previous work that studied how animals respond to color stimuli, the researchers’ hypothesized that wearing colors that are “worn” by water anoles themselves would be less frightening to the lizards. The results seem to prove that this is the case: researchers wearing orange shirts reported seeing more anoles per hour and had a higher anole capture percentage.

There were some surprising findings, however, one of which was that wearing the color green, which tended to camouflage the scientists in the forest, was less effective than wearing a very bright orange.

That demonstrates that we may not quite yet understand how animals view the world. The researchers concluded that both they and ecotourists need to recognize that animals have different perceptions than we do as humans. Wildlife species have their own “lenses” based on their unique evolutionary histories. What we imagine is frightening for an animal might not be; conversely, what we think is nonthreatening could, in reality, be terrifying.

Geckos, guns and finches

In 2017, a similar research project—which involved a run-in with the law—found that geckos, too, are mindful about the colors we wear.

Breanna Putnam of the University of California, Los Angeles, and the Natural History Museum of Los Angeles County often studies the impacts of nonnative species on the environment. The research requires her and her colleagues to wander neighborhoods and industrial parks catching anoles or other lizards by day and geckos by night. But searching the walls of buildings with flashlights at night meant that people sometimes mistook the researchers for criminals.

One night, as Putnam and a research advisor spotted geckos hanging out at an abandoned auto dealership, two Orange County sheriffs approached them with guns drawn. Luckily, a bag full of geckos made it easy to convince the officers that the biologists were who they said they were, but it was impressed upon the researchers that they needed to do something to make themselves more conspicuous and more official.

Putnam and her team designed bright-orange, Urban Nature Research Center “Don’t Shoot Me” shirts in the hope that people would understand their mission and be more inclined to talk with them before jumping to conclusions. The researchers, however, suspected that their T-shirts would make them more noticeable to lizards, which got them wondering whether or not clothing color could impact the results of their studies.

Putnam looked at previously published research and found that several species of birds with orange or red body patches are more tolerant of people wearing orange or red clothing.

In separate work, Nancy Burley of the University of California, Irvine, noticed that the colored bands she used to individually identify her zebra finches affected their preference in sexual partners, thereby messing up her research on mate choice in birds. The finches seemed to prefer black, pink and red leg bands and were repelled by blue and green.

Burley theorized that birds are attracted to their own body colors, especially if they were colors tied to mate choice. She developed what is known as the “species-confidence hypothesis,” which argues that animals use colors to become “confident” that their potential mate is of the same species, helping them avoid hybridization.

So, Putnam decided to test her newest hypothesis on western fence lizards (Sceloporus occidentalis). Males, nicknamed “blue-bellies,” visually communicate by the blue patches on their abdomens and throats.

Wearing different colored T-shirts—dark blue, light blue, gray and red—Putnam measured how close she could approach lizards before they fled. After they bolted, she determined how easy they were to catch. She tested lizards that were accustomed to the presence of humans, as well as lizards that had little experience with us in their protected nature reserve. She completed 30 trials for each T-shirt color and used high-tech equipment to measure the conspicuousness of the T-shirts in the environment.

Putnam’s research, published in the journal PLOS ONE, showed that regardless of a lizard’s previous interactions with humans, the animals are preferentially biased toward dark blue, supporting Burley’s species-confidence hypothesis.

But the main takeaway, says Putnam, is that what you wear can influence how close you can get to an animal before it flees, which has implications for ecotourists who want to approach wild animals in order to take photos. It can also affect research outcomes, if animals are hard to find and catch.

A new era of color science: flies, shrimp and wasps

What’s exciting is that we could be on the threshold of a new era of color science, with far-reaching implications on everything from the clothing industry to our understanding of animal and human behavior.

For example, it was recently determined that mantis shrimp have four times as many color receptors as we do. We have three—blue, green and red—while the shrimp have 12.

Mantis shrimp use those extra color channels to analyze light coming from objects in ways much different than humans and most other animals. Their analysis of light mimics that of a spectrometer, which physicists use to measure how much light there is in a set of wave bands. Instead, we, and most other animals, transform the relative amounts of light in different wave bands into a single continuous percept: the sensation we call “color.”

In another example, no human has yet set eyes on “bird white.” What we think of as white is probably something completely different to a bird, depending on how much ultraviolet light (UV) there is. If there’s as much UV as blue, green and red, that would be “bird white.” If there were no UV, then that would be a saturated primary color to a bird, one we cannot imagine.

Another recent finding in the field of color biology suggests patterns of color on a species can signal how well an individual can fight. Dr. Elizabeth Tibbetts of the University of Michigan first noted that black facial patterns vary on paper wasps. She then discovered that females with larger or a greater number of irregular black marks on their faces tended to win fights with their rivals. Those facial signals help reduce the costs of conflict.

Lots of animals have color patterns that convey information about fighting ability: birds, fish, insects, lizards and mammals. It’s the animal version of advertising your fighting prowess with a karate belt color. If you are a wimpy wasp, it doesn’t make sense to challenge the strongest wasp in the neighborhood. In addition, a color patch may signal one thing to a mate, another to a rival, or be seen by a member of your own species but not by a predator because of different visual systems.

Currently, research is being conducted on why biting flies are reticent about landing on black-and-white, striped surfaces. In the future, certain patterns on clothing could help to deter particular insects from bothering humans.

In the meantime, though, we, as ecotourists, can use such scientific results to reduce the disturbances we cause to the wildlife we love to view.

Here’s to finding your true places and natural habitats,

Candy