I would argue that I'm actually older, but it's not by much, and I'd just be digging myself a deeper hole, so...yeah.
I was trying to plan the idea that the rest of the humans went into hiding, maybe even planning a counter-attack, but I'm not sure where they would hide that didn't have animals.
The birds, and possibly insects, mutated first, but because it didn't affect their appearance, nobody really noticed. From there it sort of spread like a disease might, affecting most mammals, certain birds, and insects like ants, bees, etc.
There are a few plots I'm considering for the story, the first being exploring the new world, and trying to figure out what caused the mutation. Another is simply trying to survive with a new intelligence that you didn't have before- this I'm thinking with the birds. You have the option to play as a raven. The birds are secretive, so you would get a different side to the story that might not be told otherwise. Because the birds find objects and run "shops" to trade with other animals(for different things, food, etc), you would get to meet a variety of new animals too.
Edit: Forgot to add, you can also choose to play as a dog, either trying to find the humans, or defending homes from the animals taking the cities. I would give you the choice of becoming a wild dog, but that would pretty much be a wolf. Unless you wanted the dog powers, or just like dogs more than wolves, but I can't imagine that's what might earn the story bad ratings, just because,"I wanted to play this animal with this different storyline"...
There would also be conflicts between the former Wild Ones, and the Last Loyals. The birds stayed nuetral in the war for the most part. They were smarter, and decided to plan how they might run the new world, I guess.