Reasons why animals use their bright colors to either impress or frighten other creatures
Most people are aware that a vibrantly colored peacock shows its bright plumage to try and impress a mate. The animal uses its colors to impress a peahen and as a form of display. However, the bird may also spread its tail to intimidate predators, also. New research shows that there is an ancestral component to why animals might be trying to either impress or intimidate.
The study was published in the journal Evolution.
The comparison between animals and their bright colors questions why some animals, like bright red male vermilion flycatchers use their feathers to attract, while other creatures, like a mountain kingsnake use their colors to mimic a venomous snake. In this case, the kingsnake is red, yellow and black to appear more dangerous and intimidating.
The researchers at the University of Arizona found a common association between color patterns of certain animals and the activity of their ancestors.
Species that used their bright colors to attract a mate were found to be descendant from animals active during the day. However, species that used their color to warn predators were found to be descendants of animals more active at night. The intimidation is also known as aposematism, or when animals use their markings and colors to deter predators.
The research team consisted of Zachary Emberts, author of the paper and a postdoctoral research associate in Ecology and Evolutionary Biology (EEB), and John J. Wiens, author and professor at the University of Arizona Department of EEB.
The time of day animals are most active
The discovery of animals active in the day or night being a factor behind their vibrant attraction or deterrence helps researchers to understand the evolution of these colorful creatures.
The study stated that it found most animals looking for a mate included birds and lizards, otherwise known as having diurnal lineage, or being active during the day. On the contrary, animals that developed warning signals were mainly snakes, amphibians and animals descendent from nocturnality.
The researchers discovered that brightly colored birds and lizards use their colors to find mates, while vibrantly colored snakes and amphibians use their colors to warn predators to stay away. The study also found that many of these snakes and amphibians are active in the daytime, but their ancestors were actually more active at night. There was no correlation between using colors for intimidation and present-day activity, the study says. In other words, the study connects the animals’ usage of their colors to their ancestry.
Many of the animals in the study had ancestors that started out very dull in color. Bright colors started to get passed on through generations because it helped the animals to either survive or find a mate and reproduce.
“This pattern generally seems to hold across land vertebrates, a group with about 40,000 species that evolved over 350 million years,” said Wiens. “It doesn't matter how a species produces the colors. The way that a bird makes red is different from how a lizard makes red, but this general pattern of day-night activity still works,” he continued.
Results from the study
There were two possible reasons given for the bright colors attributed to various animals in the analysis, specifically the ones that deter predators. One is that amphibian and snake ancestors had no benefit in having bright colors attributed to mating since they were nocturnal. Therefore, researchers believe that the bright colors for these animals evolved to form as a warning signal to predators. The research team even found that animals that can’t see have evolved with vibrant colors.
“Warning colors have evolved even in species with no eyes,” Wiens said. “It's questionable whether most snakes or amphibians can see colors, so their bright colors are generally used for signaling to predators rather than to members of the same species.”
The second idea that explained results of the study was that the bright colors would give animals typically just enough time to escape from a predator. “The most straightforward potential explanation for this trend is situations where an animal is disturbed at times of inactivity,” Emberts stated. "When they're sleeping during the day and a predator disturbs them, that bright coloration becomes important.”
The researchers analyzed 1,824 land vertebrae species to find a connection between night or day activity and the animal’s vibrant colors. The study included all the major groups of land-living vertebrates – birds, amphibians, lizards, mammals, snakes, crocodiles and turtles.
Some animals can both attract and deter
As mentioned with the peacock, some species can use their colors to both attract and scare off other animals. However, certain colors of animals seem to represent certain levels of attraction and intimidation.
“It's interesting to see that for some colors like red, orange and yellow, they're used with similar frequency as both a way to avoid predators and as a way for mate attraction,” said Emberts. “On the flip side, blue coloration was more frequently associated with mating as opposed to predator avoidance.”
The research team wants to use this study to take a look at insects and plants in the future and the functions of colors as they change over time.
This study shows how colors play an important role in the survival of certain species.
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