Certified feline behavior and training consultant, Dr. Marci Koski, said that cats are incredibly flexible and agile animals, which makes them simply beautiful to observe, whether they are running and jumping, or slinking low to the ground to stalk a potential prey item or toy. "One of the reasons for this flexibility is their spine; it acts almost like a spring so that they can crouch and leap long distances, or twist their bodies around much more than most mammals," Dr. Koski told Bored Panda.

According to her, most cats can stand on their hind legs, as long as they have two of them. Interestingly, the tail also helps aid with balance and may assist with this posture, but even cats without tails can stand on their hind legs.

Dr. Koski said there are a few reasons why cats may stand on their hind legs. "First, standing up gives them a little bit of a boost in their view from a different height or angle; cats are curious by nature, so when they hear a noise or see something from a distance they might want to get a better look at, they will sometimes stand on their hind legs to get a better look."

Next, standing on their hind legs can help a cat look larger; this is a survival tactic that cats use to intimidate or fake-out aggressors and predators. "It's better to scare an opponent off than have to fight them. They may stand up on their hind legs, stand sideways on all fours, arch their back, and fluff out the fur on their bodies (called piloerection), all in an effort to tell an opponent 'you don't want to mess with me'."

"Lastly, cats will stand on their hind legs for treats, petting, or attention when they want something. I personally think they know how cute they look when they do this, since my cats never fail to get rewarded when they perform this action with me (they've got me trained very well)."

OK, maybe my penguin theory isn't backed up by scientific research, but at least me and Dr. Koski agree on one thing -- these kitties look absolutely adorable.