All jokes aside, I've always suspected that cats bond to their humans closely. They choose us; every cat I've ever adopted chose someone of their own in the house to be theirs. The cat I selected chose my husband, the cat he selected chose me, etc. And when I lost my cat of 12 years, my heart absolutely broke. It's been almost two years and I'm still not over it. She was one of my best friends in the world.
Science has proven that dogs have powerful connections to their humans, and that they make the same attachment hormones as we do when they look in our eyes. It turns out that cats may bond to their humans even more than dogs do, which makes sense. After all, they domesticated us, not the other way around. Plus, cats are so independent it makes them harder for us to read, unless we know them well.
It really doesn't matter, since we all bond with our animal companions, but who do you think bonds more with humans--dogs or cats?