You're can't rewind an animal x million years and place it in the same environment. You have to rewind the rest of the ecosystem as well. One possibility, for

You're can't rewind an animal x million years and place it in the same environment. You have to rewind the rest of the ecosystem as well. One possibility, for example, is that when eagle's eyes were less specialised for air to ground hunting, rodents were less specialised to hide themselves from airborne predators - because they hadn't had selection pressures from such specialised birds of prey.