Have you ever looked down at your dog and said, "You're making that sad puppy face again!"
And your dog is way past being a puppy? Well, you're not imagining it! Dog scientists say that when dogs were domesticated about 33,000 years ago, dogs figured out that when they made that sad puppy face, humans just melted. Therefore, the muscles in their dog faces evolved and now we give them bites of our hamburgers whenever they want!