Darwinian puzzle

A Darwinian puzzle is a trait that appears to reduce the fitness of individuals that possess it.

Several human traits pose challenges to evolutionary thinking, as they are relatively prevalent but are associated with lower reproductive success through reduced fertility and/or longevity.

The phrase "Darwinian puzzle" itself is rare and of unclear origin; it's typically talked about in the context of animal behavior.

Darwinian puzzles are evident in nature, even though it appears to reduce the fitness of the individual that possesses it.

Different individuals use the odd phenomenon in particular ways such as toxins, fitness demonstration, and mimicry.