The riotous colors of tropical wildlife, from rainforest parrots to coral reef fish, have long fascinated observers.But what evolutionary pressures led these animals to develop such striking appearances?

According to Oscar Puebla, a fish ecologist at the Leibniz Center for Tropical Marine Research, color serves as a crucial communication tool for animals. “It could be communication with members of your species – such as, to attract a mate,” Puebla told reporters.”It could be communication to predators to make the point that you’re venomous. It could be camouflage to escape predators.”

The methods and motivations behind this color-based communication vary widely.Birds often obtain colored pigments, such as carotenoids, through their diet. They then use these pigments to attract mates or establish dominance. Fish and mollusks, on the othre hand, employ complex microscopic structures within their cells to manipulate light, achieving camouflage by changing their color. Regardless of the specific mechanism, tropical environments have substantially influenced this evolutionary adaptation.

Roberto Arbore, an evolutionary biologist at the Research Centre in Biodiversity and Genetic Resources specializing in parrots, notes the link between diversity and color. “There’s a correlation between the diversity of a certain community and the amount of color or diversity in color that the different species display,” Arbore said. “If you live in a very diverse community, such as a rainforest, you need to recognize individuals of the same species because interacting with individuals of different species can be very costly in terms, for example, of mating.”

Birds heavily rely on their vision.The high number of bird species in rainforests intensifies the competition to stand out, resulting in the diverse colors and patterns seen in parrots, hummingbirds, toucans, and other tropical birds.

Puebla advises caution when interpreting these colors.”We have to be careful always with these colors and color patterns,” Puebla cautioned. “The way we perceive colors could be very different from the way other animals perceive it.”

In marine environments,the way light behaves underwater adds another layer of complexity. Red light is quickly absorbed, making red an effective camouflage color. Similarly, patterns that seem conspicuous to humans can help small fish blend in with the vibrant backdrop of coral reefs.

“Reef fishes have a lot of blue and yellow, but many fish do not see that,” Puebla explained.”These are colors with a very strong contrast, so they use that to break their silhouette as a way of camouflaging.”

Beyond the evolutionary pressures of diversity and visibility, there’s also a physiological aspect to the abundance of color in tropical animals, according to Arbore. producing color, whether through pigments or microstructures, demands energy. This energy is more readily available in resource-rich tropical environments compared to harsher climates like the tundra or desert.

“Normally, tropical habitats are more rich,” Arbore stated. “The conditions are more generous in terms of energy, the availability of food, a milder climate, which has a strong impact on the physiology of animals in tropical environments. Different species can actually invest more energy in color because there is more abundance and the physiological cost of being very colorful is reduced.”

Ultimately, an animal’s color is deeply connected to its environment. The complex interplay of competition and abundant resources in tropical ecosystems fosters a remarkable explosion of vibrant color in the animal kingdom.