I'm quite curious on how animals view incestual pairings. Given there are enough mates around, i have quite observed that most females (subjects are dogs, cats, pigeons and chickens) would go choose another mate that is not a direct family member (parent, sibling, offspring). How does this work? Is it instinct to not favor family members or does it still revolve around who's the fittest mate?
Anecdotally I have never observed a preference in lab mice, but we have never made a detailed study of it. Males do not seem to favor non-incestuous over incestuous breeding. Though inbreeding does tend to produce smaller litter sizes over generations and inbred strains of lab mice do tend to be less hearty. Though lab mice are a bit removed from the situation in the wild.