I always thought animals don't really choose their mates, they usually just go with the one that hasn't died yet because mating with something that's been eaten or is decaying doesn't work at all.
With some species you get individuals who are just... shunted out of the mating process because of competition from other individuals. I think that might be one more reason humans are less likely to evolve. We're (mostly) monogamous. We don't have an elite segment of society which breeds while the rest toil in unbreeding misery.
And many animals do choose their mates. Take birds for instance. Lots of species have really bright, colorful males who use their appearance to woo females and the females pick and choose among the shiniest, featheriest birds. We humans are a bit more complicated than that. We find appearance attractive, but also personality, and a whole lot of other things go into who we have children with, if we decide to do that at all.