I grew up on a very nice street where every household had two pets – one dog and one cat.  The dogs would bark and the cats would meow.  The dogs each lived in a dog house and every cat had a litter box. Every household had one of each and we called them dog and cat.

Then one day when I was older I wandered onto a new street in my neighborhood I had never been to before.   There I met a family that also had two pets – but this time both were dogs.

Not having seen such a thing before I asked them which one used the litter box and they laughed and said they don’t even have a litter box – they have two dog houses instead.

I then looked at the dogs and laughing asked, “But how do you pick which one meows?”

“Neither of them meow silly.  These are both dogs.”

Still confused I said, “But how do you know which one to call cat?”

“We don’t call either of them cat.  You see, these are both dogs.”

“But how do you have two pets without one of them being a cat?”

“Oh, we still have two pets.  And we love them very much, and they love being with each other, but they are both dogs.”

I thanked the family for helping me understand.  I walked home thinking this was also a very nice street and I was happy my neighborhood had grown.