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Choosing Partners > Choosing Partners - Pg. 221

Chapter Eight: Jaw-Dropping, Mind-Buzzing Science Choosing Partners If camouflage is so important for survival, then why are some animals brightly colored? How can natural selection explain something as flamboyant, beauti- ful, and seemingly useless as a peacock's tail? Peacocks with smaller, duller tails would be less visible to predators, so it seems that they would be more likely to survive and that colorful tails should never have evolved. Yet they have. Why? The answer is a form of natural selection called sexual selection. While it is not as important as other aspects of natural selection, it does account for many of the features that otherwise seem to have no evolutionary explanation. Darwin's theory of sexual selection states that an animal must do more than merely stay alive to pass its traits on to later generations--it must also have off- spring. And the only way to have offspring is to mate with a partner. So evolution will tend to favor those animals that are best at attracting mates. Unattractive an- imals will tend to have fewer offspring, and their features will die out. But what determines "attractive"? This is a mystery no one has yet figured out. Whatever the reason, we do know that many animals regard certain fea- tures as especially appealing. Peahens (female peacocks) think that the pea-