Why Animals Evolved Different Colors

What caused animals to evolve different colors? Why do individuals from the same population display different color morphs? Scientists have now examined a species of fish to unravel this mystery in evolutionary biology.

In many species of plants and animals, you can find different color variants among the same populations. Yet scientists have long wondered why, over time, one color doesn't eventually replace the other through natural selection. In order to find out, researchers looked at the red devil cichlid, a Central American species of freshwater fish.

The scientists looked at two colors of the red devil cichlid: dark grey through black and yellow through red. While the gold color fish genetically dominate, though, the dark-colored fish are more common.

The researchers filmed the fish over both dark and light surfaces. The scientists then analyzed these screenshots to measure the amount of change to the shade of the fish's body color. After analysis, the researchers found that the darker fish could alter its brightness to match the surface it was on, and the gold colored fish couldn't.

"These results suggest that differences in the ability to match backgrounds could play a potentially important role in maintaining color frequencies in the wild," said Will Sowersby, one of the researchers, in a news release.

The findings reveal why these two color variants manage to exist in the wild. While the darker fish have a survival advantage, the gold fish have a genetic advantage. This reveals how different color morphs come to be. That said, the work on this subject isn't over.

"Given the complexities of color variants in species, more work is needed to understand how differences in coloration might influence the susceptibility of dark and gold individuals to different predators and under different environmental conditions," said Sowersby.

The findings are published in the Journal of Evolutionary Biology.

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