The reproductive strategy of a species also matters. Species that produce hundreds or thousands of young (and then winnow down to the survivors) are better at

The reproductive strategy of a species also matters. Species that produce hundreds or thousands of young (and then winnow down to the survivors) are better at quickly "breeding out" genetic flaws (if 50% of the young die, it's not a big deal), and have an easier time recovering from population bottlenecks. Vs large mammals where raising one genetically-hobbled offspring (who then dies, or fails to reproduce) is a huge loss to the potential of the species.