Maybe it's their adorable faces, their puppy dog eyes, or maybe it's just because they've become a member of the family.

Those things are all true of course, but there's an actual scientific reason why we love dogs.

Evolution has allowed our dogs to develop what is called the levator anguli oculi medialis.

Yeah, that's a mouthful.

So let's just call it by its simpler name, the inner eyebrow raise.

You probably see it most often when your dog looks worried that he won't get a bite of your sandwich, or when he seems sad after his ball rolls under the furniture.

You may be surprised, but actually researchers have been studying facial expressions in animals for quite some time.

An animal who has similar movements to dogs?

Horses.

An animal who has little to no movement at all?

Cats.

The team studied both dogs and wolves and found that despite facial muscles being almost exactly alike, wolves didn't possess the levator muscle.

Researchers believe dogs who have facial movements more closely resembling humans have been favored unconsciously by humans throughout evolution.

So your puppy's been playing you this whole time.

And we bet you're okay with that, because guess what?

You know that amazing feeling you get when you fall in love?

Dogs give you that exact same feeling.

Need proof? Just look into their eyes.

Not only are those puppy dog eyes cute, but scientists have also studied the connection between humans and canines when they make eye contact.

Studies have found that while gazing at your four-legged friend, Oxytocin spikes in both you and your dog.

Oxytocin, also known as the love hormone, is responsible for human behaviors associated with relationships and bonding.

This means that we really do think of dogs as a part of our family.

This hormone is the same one that bonds parents and children leading scientists to believe dogs do feel more like they're a kid in a family rather than an underdog in a pack.

So the next time your best friend says you treat your dog like your child, just tell them, they practically are.

This idea also mimics the behavior of dogs since they were domesticated.

Unlike wolves, but similar to children, when dogs are confused they look to their human for guidance.

So whatever it is, that adorable face or that special bond we share with them.

Evolution has shown the unique relationship we have with dogs is only getting stronger.

Now we just have to ask ourselves, how is it possible to love them any more?