February 11th, 2013, 02:17 PM
Could our body frame indicate a type of prehistoric rutting behavour that our hominid ancestors took part in?
Such rutting behavoir may well explain why we walk on two legs.
What do you thinK?
The Cave Art Paintings of the Chauvet Cave
The Sorcerer (cave art) - Wikipedia, the free encyclopedia
Any evidence in prehistoric cave paintings, i'm not sure. Take a look.
Paul.
Last edited by pfrankinstein; February 11th, 2013 at 03:08 PM.
Or perhaps our ancestors are simply bad drawers.
hmmm ... to try and explain bipedalism in humans (something that has been with us and our ancestors for more than 3 million years) with evidence from less than 50,000 years old seems a bit dodgy to me
Many eccentric physical traits in the animal kingdom evolved with the sole purpose of securing breeding rights and becoming dominant. The stags antlers are a good example of this, they sprout just in time for the rut and drop off soon after breeding season finishes. Our bipedalism is our eccentricity and i believe the cause is very similar to that of the stags.Originally Posted by marnixR
I should imagine that the earliest ruts by our hominid ancestors were most vicious and bloody affairs, over time less so, traditions can last for in a societies for long periods of time. As we became better communicators and so more civilised the tradition died out.
Better than the 'aquatic ape hypothesis' me thinks.
Paul.
ok, maybe broad shoulders might come in handy for a wrestling match, but narrow hips ? surely that's to do with locomotion ?
but i'm still not convinced that ice age cave paintings even intend to show human beings in a naturalistic way - they're more like stick men
The hypothesis seems to me to be seriously unlikely. Upright stance is probably at least 6 million years old (recent re-evaluation of evolutionary dating) and is seen in our distant ancestor Ardipithecus.
My own view is that it is associated with tool making and tool use. While the first knapped stone tools are found associated with Homo habilis about 2.5 million years ago, earliest tool use would have preceded this a long time before. After all, modern wild chimps make and use simple tools. If Ardipithecus was more reliant on tools than modern chimps are, it should push evolution to upright stance.
A rut is a breeding season. That doesn't apply to humans, who are fertile throughout the year.
It's not the worst hypothesis, but don't apes have narrower hips and broader shoulders than humans anyway?
I think the simplest explanation for bipedalism is simple limb specialization. Apes have hands on all 4 limbs because they need them for climbing trees. However a foot is a better way to walk over land than a hand. When our progenitors came down out of the trees and began to walk around on the savanna the hands on their hind legs would have started evolving to be more foot like. The hands on the forelimbs are still needed for tool use (however basic) and grasping so they would remain hand-like.
Gradually more and more of the effort of walking would be transferred to the hind legs (since they have feet at the end now, instead of hands).
If you don't mind changing the direction of the thread, maybe we could discuss the rutting hypothesis to explain why men (on average) have broader shoulders than women (on average)?
Clearly birthing and pregnancy play a strong role in causing women to have broader hips (on average). Not a great mystery for that part, I guess.
Yeah. And multiple advantages to a trait work better than a single one.
That's a problem. Most species fair better when they're easily identified by their own kind and by other species. Moreover, contrary to common sense - often even predators and prey display clear species ID markings or signals to each other. Sexual selection must take second place here because it can't even begin if the prospective mate is getting mistaken for another species. The tendency is to emphasize whatever sets one apart from similar species in the range. The advantages of plain identification are so basic, even plants and fungi play the game.
So we should be appearing different from chimpanzees, for the sake of difference. Likewise of course they should be appearing different from us.
On the other hand, great apes often frighten competitors or predators by mimicking homo sapiens: they assume bipedal posture and show the freedom of their arms. That contrived display is actually our passive appearance. Are they copying us, or did we find that display especially helpful in our early career, or both?
i think it's all part of trying to look bigger and more dangerous to the would-be predator
so in essence, i don't think great apes mimic us, they merely do it for reasons that make sense to them (and may have done so to our ancestors before they became fully bipedal)
That does make most sense.
Why look different from Chimpanzees if your are a chimpanzee? Is the creation of new, different identities productive in that way?Yeah. And multiple advantages to a trait work better than a single one.
That's a problem. Most species fair better when they're easily identified by their own kind and by other species. Moreover, contrary to common sense - often even predators and prey display clear species ID markings or signals to each other. Sexual selection must take second place here because it can't even begin if the prospective mate is getting mistaken for another species. The tendency is to emphasize whatever sets one apart from similar species in the range. The advantages of plain identification are so basic, even plants and fungi play the game.
So we should be appearing different from chimpanzees, for the sake of difference. Likewise of course they should be appearing different from us.
Could it explain why some groups of humans physically look different from others? (Black, White, Asian?)
Not sure. It might be a ploy to make themselves appear physically larger.
On the other hand, great apes often frighten competitors or predators by mimicking homo sapiens: they assume bipedal posture and show the freedom of their arms. That contrived display is actually our passive appearance. Are they copying us, or did we find that display especially helpful in our early career, or both?
It depends also on how many species of predator find the human appearance to be intimidating. I haven't heard of a lion or tiger or bear leaving a human alone simply because it could see they were human.
We were never chimps. We and chimps split from a common ancestor; that presumably was kinda half-way, minus some diverging and perhaps converging traits later evolved by each side. How we split initially is predictable by modern chimp and human tendency to divide along cultural or technological lines, exclusion to the point of attempted genocide. Presumably our common ancestor also had this innate ability to self-speciate. Then the opposing populations (which no longer interbreed) follow the old general rule that it's better to be easily recognized for what you are than to be mistaken as something else.Why look different from Chimpanzees if your are a chimpanzee?
This is difficult because we haven't been in the wild, in their faces interacting with them for some time. Predator mammals pass their knowledge of what's a good target to their offspring, but also learn over their lifetimes. I imagine that, once we took to swinging sticks around (rather than swinging around them), and learned to throw rocks with reasonable accuracy, we'd have been a pain in the butt to most predators. Other targets like ...ehm, our chimpanzee cousins at the next waterhole... are less hassle to predate. See, the porcupine is a pain in the butt, yet each generation of bear or mountain lion must learn from experience to prefer opossums.It depends also on how many species of predator find the human appearance to be intimidating. I haven't heard of a lion or tiger or bear leaving a human alone simply because it could see they were human.
There is a sub set of human males who have wide hips and narrow shoulders. Sort of pear shaped guys. It is a trait that runs in families. When my kids were young we lived next to a family with this body style. George Washington was one of these. They breed just fine.
They also rely more on scent than on eyesight to make those distinctions.
This is difficult because we haven't been in the wild, in their faces interacting with them for some time. Predator mammals pass their knowledge of what's a good target to their offspring, but also learn over their lifetimes. I imagine that, once we took to swinging sticks around (rather than swinging around them), and learned to throw rocks with reasonable accuracy, we'd have been a pain in the butt to most predators. Other targets like ...ehm, our chimpanzee cousins at the next waterhole... are less hassle to predate. See, the porcupine is a pain in the butt, yet each generation of bear or mountain lion must learn from experience to prefer opossums.It depends also on how many species of predator find the human appearance to be intimidating. I haven't heard of a lion or tiger or bear leaving a human alone simply because it could see they were human.
You seem very fixated on the appearance differentiation theory. My problem with that theory is that there are a bazillion easier ways to differentiate one's appearance, most of which require a great deal less drastic change. Why would nature not choose the easiest path?
We were never chimps. We and chimps split from a common ancestor; that presumably was kinda half-way, minus some diverging and perhaps converging traits later evolved by each side. How we split initially is predictable by modern chimp and human tendency to divide along cultural or technological lines, exclusion to the point of attempted genocide. Presumably our common ancestor also had this innate ability to self-speciate. Then the opposing populations (which no longer interbreed) follow the old general rule that it's better to be easily recognized for what you are than to be mistaken as something else.Why look different from Chimpanzees if your are a chimpanzee?
Sorry to take your quotes out of order. However, this seems a good explanation for the appearance gaps among modern human populations also.
However you'll notice that the only required change in order to establish a new cultural identity is just color of skin. For hairy animals, I would think that color of fur would do just as well.
Modern humans are free to simply wear different looking clothes. So I wonder..... do you think the division of humanity into the three main ethnic groups happened prior to the discovery of clothing? Maybe sapiens simply needed three factions so they could make war on each other?
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