By CHAD O'CONNELL

Why humans have butts and why humans love them.

The Most Important, Most Amazing Body Part
A breakdown of the human butt, why we have them, and why we love them. 
What is a butt, really? You could call it the muscle group we sit on; where the legs connect to the torso; a squishy, important layer of fat around our pelvis; where farts and poop come out.
Any and all of those statements would be mostly correct, and yet still don’t capture all that the butt does for the human body. You could even say our butts are what makes us human. 
So, why do we have a butt?
In short: because we walk on two legs rather than four. Standing up and walking around requires an especially strong set of muscles powering our thighs and stabilizing our core, and the butt serves as a near constantly engaged machine that keeps us in motion. Without a muscled butt like ours, we wouldn’t be able to run and sprint—skills we relied on to hunt protein sources as humans made it through the last 300,000 years.
To fully understand all that makes up a human butt and why ours are so different, let‘s break it down—part by part.
Butt Biology
The Cheeks
Our butt cheeks are uniquely pronounced compared to the rest of the animal kingdom, and that’s because of the extra important role our butt muscles play in keeping us upright and in motion on two legs. The top layer of the butt is the skin—dermis and epidermis—which is very different here than skin on the rest of our bodies. 
Butt skin is thicker, toughened to withstand long periods of sitting, and the glands and pores (hair follicles) here are different too. We have more stem cells in the hair follicles of our face skin, allowing skin to repair damage more quickly and effectively than wounds elsewhere on our body. The follicles that make up our butt skin have more hair and less stem cells, resulting in a higher risk of clogged pores and acne. For that reason, pimples and scars last much longer on our butts. Also for that same reason, our butt skin can be treated with higher concentrations of active ingredients.  
The Muscles 
You’re likely familiar with the famed grouping of muscles that make things happen within those cheeks: the gluteus maximus, gluteus medius, and gluteus minimus. But you may not realize just how much they do for our bodies, from reducing back pain when we sit all day to keeping ballet dancers on their toes and powering the bulk of a boxer’s right hook.
Connected to our vital pelvis and hip joints, these are the muscles that make us move, as well as the muscles that make our butts look the way they do. The gluteus maximus is the largest, most powerful muscle in the human body working against gravity so we can stand, run, climb stairs and jump; it’s the star of the show. Exercises and movements that target the gluteus maximus alone won’t impact the whole butt, though—to enhance the size and shape of our backsides, we’ve got to activate all three. The same goes for stretching all of the butt muscles after a good workout for proper recuperation.
The Butthole
Between our butt cheeks, within the crevice where the sun formerly didn’t shine, lies the butt hole. The anus. One’s bullseye if you will. The skin here—perianal skin—looks different as we get closer to the target, because it does very different things. It can expand to accommodate a larger situation; it can be darker colored and is more delicate as we near the sphincter, where it becomes mucosa soft tissue—the same tissue found on our lips. While the average person may feel most familiar with the function and purpose of this part of the butt, scientists still aren’t sure how and when exactly the anus first became a part of human biology—an unfortunate side effect of the societal taboo in talking about our butts. 
While we’re still figuring out how it got there, we do know some things about this exit door for our digestive system. We know it can stretch to surprising sizes, for example, and that it contains erogenous zones that can cause an orgasm. Many of us learned the hard way how different and delicate the skin around the anus is via superficial tears called anal fissures—a common discomfort caused by constipation, a low fiber diet, chafing from toilet paper, and really any irritating friction. Staying hydrated helps keep stool in a comfortable state as it exits, and homeopathic homecare includes remedies like sitz baths, but the biggest thing one can do to maintain a healthy butthole is to get used to checking in on it and detecting discomfort before it becomes more. 
Beauty & Brains
By many definitions, it’s the anus that makes a butt. And although we aren’t done destigmatizing the butt hole just yet, humans love butts. Humans have seemingly always loved the look of butts. Since the earliest traces of human existence, the female buttocks have been a symbol of fertility and beauty—statues created as early as 24,000 BC feature exaggerated buttocks, hips, and thighs. Michelangelo sculpted one of the most iconic butts of all time when he made David in 1501. Spanking scenes can be found across Victorian-era pornography in the 1800s, and British physician and sexual psychologist Havelock Ellis posited that fashion innovations like the corset and bustle were designed to enhance a rounder rear. 
Although modern science is still catching up on adequate studies from female perspectives overall, there are a few scientists that have studied women’s attraction to an aesthetically healthy butt. Their observations suggested a rounder, defined butt implied healthy muscle function and thus brings associations of vitality, masculinity and performance as a provider.
American society loves butts more than ever in today’s body positive, pro-sex and post-twerk era—the infamous butts of David Beckham and Kim Kardashian alike are recognized and admired in most households. In 2020, an estimated 396,105 people had buttock augmentation surgery—commonly referred as a Brazilian Butt Lift, or the abbreviation “BBL”— showing a 19.3% increase from 2016. Big butts are in, and it’s brought appreciation for this body part to a whole new level.
The most ironic thing about our love of butts is that the juiciness of the human booty is actually, possibly, a very intentional step in human evolution. You see, our brains take a ton of energy to power. We have large brains in proportion to the size of our bodies, and this has led some anthropologists to suggest that our body fat helps support our metabolically-hungry brains when food gets scarce. So our butts—these aesthetically-pleasing, uniquely large body parts that set us apart from the rest of mammalian butts—go hand-in-hand with the brain that allowed us to become the dominant species on Earth. 
That’s what we mean when we say that your butt is your best asset. It powers our bodies; it gives us that boost to get it done, physically and perhaps mentally too; our butts make us uniquely us, and we should care for and flaunt them with pride. *