https://massivesci.com/articles/butts-sh...explainer/
EXCERPTS: What makes humans different from other animals? Ask any ten people and you're likely to get ten different answers, ranging from our relatively large brains, to our incredible use of language and symbols, to our ability to dramatically modify the world around us. But if you asked me, I'd say that it's our butts.
Take a look around the animal kingdom. Even our closest living relatives among the great apes (chimpanzees, bonobos, and gorillas), don't have proportionally as big butts as humans do. The main reason for this probably comes down to our unique style of locomotion. We're the only mammals alive today whose primary way of getting around is walking on two legs. And becoming upright bipeds has had some important consequences for our derrières.
[...] The pelvis is made up of three parts: two innominates (or "hip bones") and the sacrum. Each innominate is also made up of three bones (the ilium, ischium, and pubis) that fuse together during growth and development. And it's the ilium that's the real difference-maker between us and our ape relatives. ... The ilium has generally gotten shorter, broader, and more curved over time, which means our butt has been on a multi-million year journey to becoming the lyric inspiring piece of anatomy that it is today.
The last thing that helps make human butts unique is the fat - which might also have something to do with us becoming bipeds. [...] Our bodies store energy as fat, and we have a relatively high percentage of it for a non-aquatic mammal. This has led anthropologists to suggest that our body fat helps buffer our metabolically-expensive brains against lean times...
[...] While all of these changes sound pretty great, our peculiarly human arrangement of muscle and fat on our backsides comes with at least one major butt-related downside: a messier pooping situation than many other primates have. Picture a quadruped, like a chimp - its trunk and legs meet up and form an angle, with the butt at the corner and its anus pointing more outward. And that opening isn't trapped between large buttcheeks. For us, there's no angle - it's just a straight line. By standing up, we've rotated the anus to point more downward, then added additional padding around it. Hence, messier pooping. Thanks, evolution... (MORE - details)
EXCERPTS: What makes humans different from other animals? Ask any ten people and you're likely to get ten different answers, ranging from our relatively large brains, to our incredible use of language and symbols, to our ability to dramatically modify the world around us. But if you asked me, I'd say that it's our butts.
Take a look around the animal kingdom. Even our closest living relatives among the great apes (chimpanzees, bonobos, and gorillas), don't have proportionally as big butts as humans do. The main reason for this probably comes down to our unique style of locomotion. We're the only mammals alive today whose primary way of getting around is walking on two legs. And becoming upright bipeds has had some important consequences for our derrières.
[...] The pelvis is made up of three parts: two innominates (or "hip bones") and the sacrum. Each innominate is also made up of three bones (the ilium, ischium, and pubis) that fuse together during growth and development. And it's the ilium that's the real difference-maker between us and our ape relatives. ... The ilium has generally gotten shorter, broader, and more curved over time, which means our butt has been on a multi-million year journey to becoming the lyric inspiring piece of anatomy that it is today.
The last thing that helps make human butts unique is the fat - which might also have something to do with us becoming bipeds. [...] Our bodies store energy as fat, and we have a relatively high percentage of it for a non-aquatic mammal. This has led anthropologists to suggest that our body fat helps buffer our metabolically-expensive brains against lean times...
[...] While all of these changes sound pretty great, our peculiarly human arrangement of muscle and fat on our backsides comes with at least one major butt-related downside: a messier pooping situation than many other primates have. Picture a quadruped, like a chimp - its trunk and legs meet up and form an angle, with the butt at the corner and its anus pointing more outward. And that opening isn't trapped between large buttcheeks. For us, there's no angle - it's just a straight line. By standing up, we've rotated the anus to point more downward, then added additional padding around it. Hence, messier pooping. Thanks, evolution... (MORE - details)