Part-Time Vegetarian?

I am struggling with the concept of being a part-time vegetarian. What exactly does that mean? Perhaps even I can be considered a part-time vegetarian when I eat my corn-on-the-cob between my lobster and my steak. Trust me, I am not easily mistaken for a vegetarian!

Source of the Life

I found this sign in a park in Beijing:

Mystery sign

I tried to follow it to see what it meant, but it turned out to be a dangling pointer.