If love is a battlefield, evolution has given animals and insects the tools for competition. Peacocks boast flashy tails and birds sing to capture the attention of mates, meanwhile, elks and dung beetles use antlers and horns, respectively, to fight off other males during courtship. These traits, which can vary widely within the same species, have long fascinated biology Professor Erin McCullough. “Sexual selection, or competition over mates, is responsible for many of the biggest, flashiest, most colorful, and conspicuous traits that we find in the animal kingdom,” she says. What’s puzzling, however, is that these traits can make species more susceptible to predators, seemingly at odds with natural selection “Reproduction is the currency that really matters,” says McCullough. “It doesn't matter if an individual lives forever — or if it lives a whole lot longer than its peers — if it never succeeds in attracting a mate, because then it won't leave any of its genes to the next generation.” -- Challenge. Change. is produced by Clark University. Listen and subscribe on Spotify or Apple Podcasts. Find other episodes wherever you listen to podcasts.