Hi, I'm new here. I'm not a herpetologist (or biologist for that matter), so if this question seem incredibly stupid, please forgive me.

I've always wonder how the American alligator's closest cousin, the Chinese alligator, ended up half way around the world, separated by thousand of miles of ocean.

I mean, the Chinese and American alligators occupy roughly similar latitude (Eastern China Yangtze River basin vs Florida and Louisiana), both a fairly northern latitude for crocodilians. But that doesn't explain the longitude gulf that separate the two alligator species.

So how did the Chinese alligator ended up in China? And how did the American alligator ended up in Southeastern US?