Putting this in the category of "almost seems like common sense, but I never connected the thoughts to come up with this".

Let's look at house pets for example - many dogs still exist because of their friendliness towards humans (we feed and shelter them). Same with certain breeds of cats.

I wonder what would happen to this ecosystem if say, humans went extinct someday? It's pretty easy to imagine we'll be the cause of our own demise so any of these animals relying on us to survive would probably go with that, but if we disappeared tomorrow I'd be curious to see how they would survive.