I’m pretty sure someone already said this but I’m not going to bother looking through ALL the posts. Each animal migrated to where he was able to survive. Why would penguins decide to head over to Australia if it was to hot for them there? obviously they’d head towards a cooler place. Same with any animal. They go towards the right climate in which they could survive and reproduce.
Why are there are no polar bears in Brazil? they should’ve distributed evenly right after Noach landed the arc?
Is basically what you’re asking. Just in case you were wondering how they got there when there’s a huge ocean in the way then I guess Noach would’ve landed the arc when all the continents on Earth were clumped together forming Pangaea.
Or you could put all that aside and go by the opinion of “it was a nes” after all, the animals did all survive in the teivah which definitely didn’t have the correct climate for all of them. But hashem doesn’t do nisim if they aren’t necessary so maybe just that part was a nes.