What if you own both?

eta: never mind. I see the story says they cancel each other out.

But this is inconsistent with the research that says that pet owners live longer. (Because there's also research that, on average, happy people live longer.)

Could it be because the happiness is self-reported?

That was research? Who knew.

Yeah, I saw that. It doesn't control for other reasons the dog owners might be happier though...other conditions in their lives.

... selection bias. What every undergraduate is taught about in introductory econometrics.