I think it could be doable?

Maybe have different animals focused on different vegetation areas? If that is possible?
Deer = forest, Horses = grasslands, turkey/chicken = bushes, ducks = near water?

v0.3
Added all animals (all enabled by default).
Animals get a random human name.

I will try it out

v0.2
Added mod options to pick animals.
Made sure it can't go over the max amount.

Fully grown trees I think.
I figured it was a way to have a decent forest before animals start spawning in.

I always felt the terraforming feature of green planet was lacking in fauna (flora alone doesn't make up a self sustaining ecosystem after all). What does 'promoted' mean for trees?