Women are weaker. . .

Factual Questions
21

It’s not.

First count, wrong. It seems fairly reasonably to posit from what we know of hunter-gather activities recorded in historical times and from paleolithic evidence that women spent a great deal of time in gathering activities: in fact they probably provided the bulk of the food consumed by human bands. We may presume that males, being largely expendable, engaged in ‘addative’ activities such as high risk hunting (as opposed to lower risk hunting of smaller creatures, as well as gathering) as well as band defense.

There is probably also a matter of inra-male competition, where size does not reflect ‘economic’ or food related survival activities per se, but rather sexual competition between males. I.e. we beat up on each other, nothing much to do with lions and tigers, oh my.

As such, the stereotypical view which follows:

is only partly correct.

That’s false on the face of it. Any review of anthropological literature indicates women often do more work, not less work than men. Rather, they have need for different kinds of strength – endurance related strength rather than fight/struggle strength.

Again, to repeat: there are probably to main aspects:

(1) intra-male competition for mates (e.g. Cher’s note above)
(2) male expendability (the species naturally produces an excess of males, and in fact the number of males needed to maintain a population is obviously not a 1 to 1 ratio).

(mirages suggestion is also worhty, although it runs into apparently decreased dimorphism.)

Muscle mass in taking down game is quite frankly absurd. We are a pitiful species in terms of physical capacity when compared even with predators of similar mass. Our advantage lies in (1) mental flexability, such as it is (2) tool making (3) capacity to act in complex groups. It strikes me as highly doubtful that muscularity in ‘taking down game’ was ever a positive selective factor. Perhaps a side benefit in certian kinds of hunting --e.g. later development of missile weapons-- but no early homo stupid enough to match muscle mass against serious prey was going to pass along his genes. I differ with Rickjay insofar as it would appear from earlier fossils that our dimorphism has decreased, suggesting a reversal of prior selection pressures.

Now, you can get back to your regularly scheduled stereotypes.

22

Rick, I asked about the breast tongue-in-cheek, I do not keep size A in my family :-).
Anyway I think, it’s always wrong to ask WHY? of nature intentions. People do things on purpose, nature does not. We tend to find good reasons. Giraff’s neck is not there to pick leaves from high brances. Giraff’s nech just happened to be long, so it’s more convenient to pick high branches than to graze, and there happened to be more high branches than grass. Man’s lungs are not larger that woman lungs, they have proportionate lungs. I think in some species the male happened to be larger, and in some species the females. And human males just carry these features from their “ancestors”, with harems and without. Some organs are larger (on absolute basis) in females (breasts). Not on purpose (I wish!), but for purpose. But I discussed breasts above.

23

It’s not.

First count, wrong. It seems fairly reasonably to posit from what we know of hunter-gather activities recorded in historical times and from paleolithic evidence that women spent a great deal of time in gathering activities: in fact they probably provided the bulk of the food consumed by human bands. We may presume that males, being largely expendable, engaged in ‘addative’ activities such as high risk hunting (as opposed to lower risk hunting of smaller creatures, as well as gathering) as well as band defense.

There is probably also a matter of inra-male competition, where size does not reflect ‘economic’ or food related survival activities per se, but rather sexual competition between males. I.e. we beat up on each other, nothing much to do with lions and tigers, oh my.

As such, the stereotypical view which follows:

is only partly correct.

That’s false on the face of it. Any review of anthropological literature indicates women often do more work, not less work than men. Rather, they have need for different kinds of strength – endurance related strength rather than fight/struggle strength.

Again, to repeat: there are probably to main aspects:

(1) intra-male competition for mates (e.g. Cher’s note above)
(2) male expendability (the species naturally produces an excess of males, and in fact the number of males needed to maintain a population is obviously not a 1 to 1 ratio).

(mirages suggestion is also worhty, although it runs into apparently decreased dimorphism.)

Muscle mass in taking down game is quite frankly absurd. We are a pitiful species in terms of physical capacity when compared even with predators of similar mass. Our advantage lies in (1) mental flexability, such as it is (2) tool making (3) capacity to act in complex groups. It strikes me as highly doubtful that muscularity in ‘taking down game’ was ever a positive selective factor. Perhaps a side benefit in certian kinds of hunting --e.g. later development of missile weapons-- but no early homo stupid enough to match muscle mass against serious prey was going to pass along his genes. I differ with Rickjay insofar as it would appear from earlier fossils that our dimorphism has decreased, suggesting a reversal of prior selection pressures.

24

My apologies for the double post. Obviously the second is the correct version. Slip of the mouse.

25

Maybe taking down game isn’t the best choice of words, but have you ever tried to drag a deer a couple hundred yards to where you could work on it? And thats today, when the wolves and various preditors that would probably start heading towards the kill have been nearly eliminated from consideration. My guess is that any human who survived by hunting was one badass mofo to get enough of the kill back to the group to survive.

26

He didn’t have to get it back to the group. The group was right there with him. Unless they were hunting small game, people undoubtedly needed to hunt together.

27

peace, expanding on cher3’s answer about why females are often bigger than males in most species (I’m speaking of overall species, not just vertebrates here), it’s simply that females actually have to lay the eggs, requiring a lot more body mass, while males who are not fighting other males just need to be able to produce and deliver some genetic material.

As far as vertebrates go, someone pointed out to me that species that form long-lasting monogamous pairs, like wolves, tend to have little sexual dimorphism. It is particualrly noticable in birds. Virtually all raptors, swans, parrots, ravens, penquins, etc. form life-long relationships and care for offspring together. There is little or no continual competition to mate, so the noticable secondary sexual characteristics seen in males of other vertebrate species have not developed. Male size and strength would seem to be related to mating rituals rather than any sort of hunting behavior, and pretty unneccessary to individual or cultural survival.

28

[QUOTE]
*Originally posted by cher3 *
**

Whoa! Could you point out to me where my post got so ridiculous? I would never intend to imply such a thing as you have claimed. If you tell what it is that I posted to make you think this, I’ll be happy to explain myself.
Collounsbury,

Thanks for pointing out the likely flaws in my understanding that male muscle mass was related to hunting. I appreciate the info. The snide comments on the other hand . . . Well, you can guess where I’d like you to put those.

29

Pregnancy is actually pretty efficient. You only require about 300 extra calories a day during pregnancy. Nursing requires about 500 extra calories a day over what the woman normally needs. And, as has already been mentioned, pregnant and nursing women might not be hunting, but they probably wouldn’t be enjoying any “down time” either. There was plenty to do besides sticking spears into things.

30

For my entirely speculative $.02.
Sexual dimorphism does appear to be fairly widespread (though by no means universal) amongst at least primates. I’s assume (with absolutely no grounds) that the beginnings of this trait were inherited from our ancestors. As far as women hunting, this is probably true, though in the case of most hunter gatherer societies it seems to be mostly small game. More gathering than hunting. With or without weapons it is a distinct advantage to be large when hunting large game. All else being equal a large man inflicts more damage with or without a weapon. So if sexual dimorphism were inherited then it seems likely that large game hunting would be reserved mostly to the males. Added to this humans have different hunting patterns to most predators. We tend to roam far and wide in small groups to find game and then drag it home, rather than the entire ‘pack’ descending on a kill. I’ve seen little evidence that humans ever attack large game in large groups. Today even animals like lions and buffalo are killed single handed. Human males also associate in tight groups to protect their harems, something rarely found in other mammals. If I were a proto-human male I wouldn’t let my females hunt, simply because of the chance that unsupervised and isolated they could be either fertilised by a male from another tribe, or actually driven into his tribal group. Even hunting in a pair with one male would place both individuals at risk of attack. They would be restricted to gathering, where they are capable of supervising and defending each other from small bands of wandering males, and where there would probably be one male from my tribe guarding them. This would mean that extra muscle mass would have little advantage.
Of course all this has probably been compounded by inter-male aggression. Larger more agressive males have more children, therefore more children are large and aggressive. Large agressive children are better hunters and so have more food, are fitter and better able to fight and so have more wives and children children and so on in a self reinforcing cycle.
Almost all pure speculation of course but it sounds good.

31

I am almost certain I have read that sexual dimorphism is established at least as far back as Australopithecus afarensis, so there is some evidence. Lucy was an afarensis, and she was smaller than other afarensis skeletons; paleoanthropologists have attributed this to dimorphism.

32

It’s always hard to reason from analogies to other species. I wonder at what point in their evolution protohumans developed sexual dimorphism?

There’s no doubt that being large and strong would be helpful in hunting large game. I just wonder whether this is a secondary benefit.

I would think, though, that men would have hunted in groups, especially when tools were less efficient. Even if you could kill a buffalo by yourself, you would want other people to help you butcher it and carry it off.

Another think I wonder about is how dependent people really were on large game. Most modern primates (other than people) make do with gathering and opportunistic capturing of small game, don’t they?

Were there periods of “human” history where large game was a primary source of food?

33

As well, I would think that Homo Sapiens’ relatively long gestation period would have something to do with it. In primitive societies, women were more likely to be pregnant for much of their adult lives (due to high mortality rates, no birth control, etc.) While pregnant, its probably difficult to participate in a hunting party. Thus, these women, the women who were desireable to the males at the time, were more likely to spend most of their time at home. These traits would then be passed on to offspring, and so on and so forth.

34

Cher.
If you’re only worried about carrying game home there still wouldn’t be any advantage in large groups of individuals going on the hunt that I can see. They make more noise and smell, and are wasting energy following a hunter when they could be foraging near camp or hunting by themselves. Personally I’d leave the other ‘bearers’ foraging around camp and guarding the women and go out hunting in pairs. When I killed something I’d cut off as much as I can carry (or not) and go back to camp, leaving my companion to guard the kill. Whoever I need can then come back with me and help me carry the food back.
True most modern primates make do with small game. Chimpanzees aren’t opportunistic about it, they indulge in organised hunts, as do some baboons. However I recall that in most tropical hunter/gather societies the calorie contribution from game/gathered reserves is about 50/50. If that’s true it makes it a primary food source. Of course even if it isn’t the fact remains that modern human males in hunter/gatherer societies spend periods of time away from camp hunting with all the associated problems.

OCC
I don’t get how muscular women wouldn’t be as attractive and fall pregnant as often as non-muscular women? Or why there wouldn’t still be an advantage in retaining your musculature to help at the hunt when you are able? Are you saying that being unable to hunt for so much of the time would mean that muscles would be a liability most of the time and so get lost from the female population, or that the habit of staying at home would get passed on?

35

I thought the whole reason we evolved differently was to keep the shoe companies in business. Different sized feet means more shoes.

For that matter, that explains the whole “breast issue” as well. If women had the same sized breasts there would be a whole lot more room in clothing stores due to the lack of variety. Without variety our economy stagnates.

Stagnation is what killed off the dinosaurs. They just couldn’t keep up with the fast paced changes in the (then) modern day world.

So celebrate diversity and the fact that we’re not dinosaurs!

36

Are you sure, guys, that you are discussing a real thing? I can make a case right now that a bigger woman would be a better nurturer and a smaller man would be a more efficient hunter, at least if the relative difference were the same? Or do you think that our common ancestor was “one size fits all” and gave rise to gatherering apes and hunting humans, in both of which males became bigger, but for opposite reasons?
The first person who will answer YES, could please answer why do we have four extremities? Six would allow for better hunting.

37

The risk/expendability factor may also partly explain why the dimorphism goes the other way in many species. Lions, for instance, are pretty much the top of their food chain, so hunting is a relatively low-risk activity. Female lions can thus do most or all of the hunting without seriously jeopardizing the pride’s future reproductive capability. Humans, however, can be either predator or prey, and are even at some danger from the animals they hunt, so large-game hunting is mostly done by the males. Even if the tribe loses half or more of its males, it can still grow at the same rate, so long as polygyny is allowed.

peace, as to the number of limbs, that’s something that’s notoriously difficult to change via natural selection. Four primary limbs goes all the way back to amphibians and fish, and a person would be very unlikely to spontaneously be born with an extra arm. Even if the mutation did arise, it’s not clear that it would be an advantage: Even if the baby were not killed at birth as a monster, what would it let the person do? Would they have the same manual dexterity with the extra limb? Would he or she be able to keep the arms from getting in each others way? Would the style of clothing popular at the time be able to fit? And finally, would said person be able to convince a prospective mate that that extra limb was a good thing?

38

I imagine you could. I think we all accept that human females in primitive societies, and indeed in most advanced societies, do most of the ‘nurturing’. By extension we assume this was true of primitive humans or proto-humans. Maybe without reason, but it seems to be common assumption on this thread. Having said that we are all postulating “Is there a biological justification as to why females are weaker in sheer strength than males? “ as the OP asked. Since ** furnishesq** has made it clear that they don’t want a physiological answer for why a modern man will grow more muscle, our speculation is based on what we assume we know about primitive humans. It would be a bit silly basing it on anything else. If the OP had asked why humans females were stronger than males I could make some sense out of what you just said, but not out of the OP. As it is we are discussing the reverse of the argument and so I can make some sense out of the OP…

I’m not answering yes but as far as I can recall from chordate zoology 1 it’s because the first lobe-finned fishes to successfully invade the land had four functional limbs. Since they are our ancestors we have inherited the tetrapod condition. As for why we or any other tetrapod haven’t developed any more fully functional limbs since….
WHAT THE F*** HAS THAT GOT TO DO WITH WHAT IS BEING DISCUSSED???

39

That’s because you’re thinking of how hunting is done today, not how it was done before the invention of civilization. Nowadays, game animals are relatively scarce and have learned (for the most part) to fear humans. It was not always so. Someone mentioned earlier “people hunting masotodons”. It’s a safe bet that the noise/smell of a large group of humans would have had no impression on beasts this large that long ago, and that a large, coordinated effort would be required to bring one down. Plus, and this is probably even more important, hunting larger animals is just more efficient. Think of it this way: say you have 10 hunter-gatherers of equal skill. Each has one full day to hunt. In that time they can kill either 10 rabbits apiece, 3 deer apiece, or one mastodon as a group.
The energy breakdown this yields would approximate as (I’m somewhat guessing on the relative weights of meat that could be extracted from each animal here):

100 rabbits = 150 lbs of consumable food total
30 deer = 3000 lbs of consumable food total
1 mastodon = 2+ TONS of consumable food total

There may be a lot of variation, but I think you see my point: hunting bigger animals is more efficient on a food per unit of energy expended basis. And societies using primitive weapons would have needed to make up their deficiencies in technology with numbers or some technique like driving animals over cliffs (which some native Americans did with buffalo occasionally).

40

Gaspode, do not yell, I hear you.
I’ll try to say this again, differently. I can see why females have the necessary devices for nurturing. By defalt, STS. But they do not any clear advantages by being 10-15% smaller (on average). Neither do males by being larger. Our close relatives, apes, and we decended from a common “ancestor” :-)* whose sexual dimorphism is unknown. Why in gathering apes the dimorphism is more pronounced that in hunting humans? This hunting hypothesis does not hold water. In many species the dimorphism is reversed. Perhaps we are so fixated on it only because this is the first and about the only difference that catches out eye and fancy? And we are barking on the wrong tree? That the difference is purely random, does not give many significant advantages/disadvantages to either sex and is actually nonessencial?
As far as six legs. I know why we have four extemities, phylogenetically. Four seems a very good number now. But was it “on purpose”? What if ealy Chordates developed six extremities? Insects have six, but can manage with four. They are happy with six, are, arguably, more seccessful than we are.
So, what I am saying, is that there is no explanation for every event in nature. My favorite example is: “Why the Moon is here”? It makes tides, romantic nights, lunar calendar, etc., but there is no real purpose: we could had no moon or two moons and not much would have been different. Not much would be different if the dimorphism did not exist or was reversed…

You like “ancestor”, don’t you?