Anyone can become an amateur ecologist, and I encourage more people to give it a try. All you have to do is be interested in observing nature and the outdoor world of plants and animals, even if you’re just in your backyard or local park. In the simplest terms, observe with a question. Color is a good starting point. When you see a plant or animal, ask yourself, why is it one particular color instead of another? The color of a bird’s plumage, a flower’s petals, a mammal’s fur can give clues to its habitat, behavior, and general ecology.
Plants with green chlorophyll or trees with brown dead leaves or limbs may not be particularly intriguing. But more striking colors of obvious significance to the existence of a plant or animal set the stage for environmental mystery. Even not-so-colorful animals can prompt the curious to wonder why they sport a particular pattern of stripes or spots. Ecologists themselves do not always agree on the answers.
The reason for some color patterns may be apparent. For example, many male birds develop bright plumage in the winter and spring. During the period of courtship, males use their enhanced colors to attract and impress females. Males of some species use their breeding colors to threaten or intimidate other males. The ready distinction between males and females assures that courtship efforts or acts of aggression are not expended on the wrong sex.
A general question can be asked about color in most mammals, which is, where is the color? Most mammals are some shade of black, brown, or white. Birds, butterflies, and lizards come in an endless array of yellows, reds, and blues. But except for a few primates, mammals seem to be stuck with varying shades of dull. Is one reason mammals have few displays of bright color because most of them are color-blind? If so, the common function of color to attract or dispel others of the same species would serve no purpose.
Ecologists often ponder black-and-white color patterns in mammals. Some have special traits that make the reason for their coloration obvious. Prime examples in North America are the skunks. The black-and-white contrast is not for protective camouflage but as a warning signal to other species. Even a color-blind bobcat quickly learns not to tangle with what might look like an easy meal. The black-and-white coloring among penguins in Antarctica, where they have no land predators they need to hide from, requires a different explanation. Penguins do dive for fish in dark waters where marine predators lurk. The bird’s black back and lighter front offer countershading that help it be inconspicuous when observed from above or below while swimming.
Some black-and-white color patterns are less easy to explain, and ecologists often do not agree on what the correct explanation is. For example, at least 14 different hypotheses have been proposed for a zebra’s stripes. One suggestion is that the striped pattern creates moving vertical lines that make it difficult for a predator, such as a lion, to focus on. Thus the herd can sometimes escape before an individual can be singled out for capture by a confused cat. Which of a dozen other explanations has the most validity is a matter for debate. You may even be able to think of an explanation for black-and-white striped zebras that has not yet been thought of.
The natural world is full of color displays. The explanations may not be obvious, but natural selection in the past has resulted in the colors we see. For whatever reason, the ancestors of the species were successful.
Next time you see a moth with pink wings, a brown chipmunk with white stripes, or a trumpet vine with orange flowers, ask yourself why it sports these colors and patterns rather than another. You can enjoy the guessing game without consulting a book or searching the Internet. Or you can make your own guesses and then find out what explanations have already been offered.
Whit Gibbons is an ecologist and environmental educator with the University of Georgia’s Savannah River Ecology Laboratory. Send environmental questions to firstname.lastname@example.org.