Why do peacocks have colorful tails?

Answer: To attract peahens during mating

To attract peahens during mating ✓ — Correct! The peacock's magnificent tail is a classic example of sexual selection. The long, colorful feathers are not actually the tail but elongated upper tail coverts. Peahens choose mates based on the quality of this display—more eye spots, brighter colors, and vigorous shaking all signal a healthy, genetically fit male. The tail is costly to maintain, which makes it an honest signal of quality.

To warn predators that they are poisonous — Wrong. Peacocks are not poisonous. Their colorful tails are for attracting mates, not for warning predators. In fact, the bright display might make them more visible to predators, but the benefit of attracting a mate outweighs the risk.

To help regulate their body temperature — Wrong. The peacock's tail does not regulate body temperature. It is a sexual ornament used in courtship displays. While the large feathers might provide some shade or insulation, that is not their primary function.