You could tell the census worker you are an ‘army of one.’ LOL!
I was thinking something along the lines of
WOrker: How many people live in your residence?
Me: What do you mean people? I think of our pets as kids....would you like me to enumerate just the mammals or are you including reptiles and amphibians...oh wait my ex husband isn’t here anymore so no reptiles.....Hang on a sec I have to go count the guppies.....