Sweet stems. Hot gams. Nice thighs. Women hear compliments like these everyday. Even men do too. It’s pretty obvious as we walk down the streets that we are a rarity; our legs can take up more than half our bodies. The gait of a human is unlike any other animal, including the apes we descended from. So, it’s hard not to ask: “Why are we walking on two legs instead of crawling on all fours?”
Picture yourself about sixty pounds lighter. You’re practically a raw vegan, you’ve skipped more than a few shave days, you’re crawling in the grass, and you’ve never read a book. This isn’t you on a cultish crash diet. This is you more than 5 million years ago before humans learned to walk.
How did we get from this root-chewing, tiny hairball to a six-foot-tall pedestrian rocking a short skirt? If crawling around on all fours worked so well for so many millions of years, then why the sudden change to standing up and strutting? What did early humans have to gain from climbing off the safety of their branches and taking a less-balanced, more-accident-prone stroll?
Today’s science has one concise answer for this: humans are lazy.