Some do it for style points -- others do it out of necessity. One, frankly, just does it to pee.
Reasoning aside, they all have one thing in common: they're adorable (and they think they're people!)
For your viewing and "d'aww"-ing-out-loud pleasure, we've compiled 10 videos of cats and dogs walking on two legs. Because it's Friday, guys.
What other animal awesomeness have you seen? Share your favorite videos in the comments.