Let’s, for a moment, pretend to be a peahen choosing a sexual mate. We have a few options, with different degrees of impressive tails. As stated in the post, it is difficult to tell whether the tail is a good proxy for fitness. Indeed one could either argue that having a big tail is a handicap for the peacock, limiting agility for example, or that it is a strong hint that the peacock is otherwise very fit, despite the big tail. I would argue that, given the information we have, i.e. all the potential male mates survived so far, we shouldn’t assume a higher/lower fitness between them.
But, why do we care anyway? We are not interested in the fitness of our future mate, but rather in the fitness of our future chicks. And here, I think, the tail is relevant.
If we have male chicks, the choice of a mate will influence both the size of their tail and other characteristics like the ability to find food, agility and so on. As before, it doesn’t seem that the tail is a reasonable proxy on how to produce better male chicks.
If we have female chicks, the story is very different. A female chick will partially inherit the agility and general ability to survive from the mate we will choose, but will not inherit the handicap of a big tail. Therefore, we should choose the mate with the biggest tail.
TL;DR: Tailed peacocks make better female chicks
Let’s, for a moment, pretend to be a peahen choosing a sexual mate. We have a few options, with different degrees of impressive tails. As stated in the post, it is difficult to tell whether the tail is a good proxy for fitness. Indeed one could either argue that having a big tail is a handicap for the peacock, limiting agility for example, or that it is a strong hint that the peacock is otherwise very fit, despite the big tail. I would argue that, given the information we have, i.e. all the potential male mates survived so far, we shouldn’t assume a higher/lower fitness between them.
But, why do we care anyway? We are not interested in the fitness of our future mate, but rather in the fitness of our future chicks. And here, I think, the tail is relevant.
If we have male chicks, the choice of a mate will influence both the size of their tail and other characteristics like the ability to find food, agility and so on. As before, it doesn’t seem that the tail is a reasonable proxy on how to produce better male chicks.
If we have female chicks, the story is very different. A female chick will partially inherit the agility and general ability to survive from the mate we will choose, but will not inherit the handicap of a big tail. Therefore, we should choose the mate with the biggest tail.