I would say that a lot of animal life was indigenous to the plqanet. After all, even tho they were the 'playthings' of the Valheru, the elves no doubt had need of some animals for food, others as beasts of burden, etc, even before the coming of man.
On a blue-green earth type planet, certain life forms evolve in the same way, whether you call it 'earth' or Midkemia'.
Some of the so-called lower life forms, like dogs, cats, cattle and horses, for example, probably made the journey alongside man. Remember that there were none of those species on Kelewan, tho they have similar ones.