This is a sign at the Davis Farmers Market. The funny thing is that there are reasons for rules to cover more than dogs. I once saw a cat on a leash at this very market. He was not happy.
I also once had a student who told us to call him Reptile Man (I am not kidding) bring a snake to class in his backpack.
shewhodaresnothing 
So pet pigs [my neighbor has two] are ok though? 🙂