Animal mobs do not spawn in Ice Plains biomes and its mutant variants. These would typically be polar bears and rabbits, which do not spawn as of the current version.
MC-126859
Polar bears and rabbits not spawning in Ice Plains
Resolved
Fixed
2
Andre Pugliese
Confirmed
Minecraft 18w10b
Minecraft 18w19a
Retrieved
Rabbits actually aren't spawning anywhere but rivers, from what I've seen anyway. I hadn't checked polar bears. This is my post about the rabbits: MC-128071