So maybe we should be careful when choosing our pets.
"I suspect it is a little bit like the way in which we choose potential partners in real life, we don't really think about it too much. There's something there that either clicks or it doesn't. I suspect that exactly the same in the pet store," he said. "There will be some considerations in terms of lifestyle and so on but when it comes to deciding between this puppy and this puppy. I suspect it's just intuitive but you could be picking up on something about its behavior that mirrors your own, that really appeals to you."
Fun-loving dogs? Emotionally sensitive cats? Funny fish? We checked into a pet store to investigate.
One dog owner who spoke with ABC News compared her Great Dane Moses to her husband, Luke.
"Moses, he is quite dopey and he's got big feet. He's clumsy and he's loving and caring as well," she said. "And Luke is like that. But he's fun and he's loving. Moses is caring and protecting and is exactly like Luke."
One cat owner described what his furry feline is like. He said, "The cat's very lazy; it comes in, eats, sits around all day. Sits at the door to go out, you let it out, it comes back in again."
His daughters said their dad also sometimes acts like that.
And another dog owner who spoke to ABC News said she and her pet are very similar.
"I am usually a happy person but I can get a bit moody, just like her," she said. "She is a bit moody sometimes, and I think we reflect each other in our moods. She's normally smiling, as you can see here, and I'm normally smiling. But catch me on a bad day and I'm a bit moody."
She also claims to have conversations with her dog. "She woo-woos, she makes a woo-wooing sound, which is really strange. … Yeah, she woo-woos back, but she usually starts it. It's usually when I get home, it's her sort of greeting."