I know there will be exceptions... but this is what I notice normally. Is it something to do with our sex or what?
Think of a stereotyped couple from the ages when these animals were domesticated (BC).
The man is masculine and adventurous. Strong and brave and his family depend on him.
The woman is feminine, housebound and must depend on their nearest male relative.
The typical dog is adventurous, strong and brave. And can also follow it's owner outside the house.
The typical cat stays in the house or around the area it knows. Domesticated cats aren't very good hunters but dogs can be trained to hunt. A cat depends on it's family for food and housing (supposably like women) and a dog can hunt it's own food for it's family and itself.
Generally we prefer the people who we share common factors with, so women have always seen their commodities with cats and men with dogs.
A dog is a "man's best friend" afterall.