How big can hominids get?

Factual Questions
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[QUOTE=Lemur866]

The other important question is, what do these trolls eat? They need a lot more food than H. sapiens, and if they live in the mountains or coniferous forest or tundra where do they get enough food to keep them going? These are places where it is very difficult for large animals to gather food. They need to be able to eat things humans can’t eat or they’re going to be outcompeted by humans. Or bears, since it looks like these trolls are filling a niche already occupied by bears.
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Well since we are dealing with myth here, I’ll go back to what the source material tells us about their diet. Post arrival of man, they have been known to consume several sheep in a sitting, kill and consume cattle, horses, and pigs. Trolls rountinely raided other goods that were produced by man such as grain stores, cheeses and milk. They are reported to have a findness for both milk and alcohol. Humans also were consumed with some regularity. Anecdotal evidence suggests that they also take wild game, fish, and vegetation, though meat seems to be preferred.

Some of the sagas seems to suggest that they exist in a semi parasitic relationship with humans, following groups of them around to pilfer their produce. Outside of contemporary fantasy, which I do not care to use as reference, there is little known about any sort of culture or family structure. This would seem to precule any sort of primitive agriculture on their part. I feel it is a resonable assumtion to think that they are filling the role of bears in the regions that they inhabit.

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I apologize for the numerous typos above; I seem to have posted the pre-spell check version.

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[QUOTE=spoke-]
You may be right, but the wiki article disagrees:

And it looks like the BBC agrees:
[/QUOTE]

Interesting. I’ll have to see if I can find the original references that’s based on.

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But take a look at a Megatherium skeleton. They were massively built, with gigantic flanges and knobs at the joints for muscle attachments.

However, given what we know of extant Xenarthran metabolism, it’s likely that ground sloths were also pretty low metabolism creatures. That is, pound for pound they probably ate less food than other mammals. Yeah, but giant ground sloths are one of those creatures that I really wish were still alive because there’s absolutely nothing like them alive today. And they are so weird that they aren’t anything close to a good model for what a large primate might be like.

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I’ve often wondered if Native American legends of “sasquatch” don’t have their origins in a distant past when there were still ground sloths roaming around.

Or maybe not so distant. According to wiki,

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[QUOTE=Fear Itself]
Perhaps, but those jaws didn’t run on Gatorade.
[/quote]

An adult human brain uses about 20 -25% of the total energy consumed by the body. What is the corresponding number for T-Rex’s jaws? (Hint: We don’t know, but it sure ain’t 25%.)

The fact that we don’t know is all the more reason that the inference should not be made.

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[QUOTE=John Mace]
An adult human brain uses about 20 -25% of the total energy consumed by the body. What is the corresponding number for T-Rex’s jaws? (Hint: We don’t know, but it sure ain’t 25%.)
[/QUOTE]
According to the requirements laid out by the OP, our fictional troll need not have the intellectual capacity of a modern human, only that it be capable of speeds enabling it to run down a human, or executing an ambush of a human. Many predators are capable of this, with much smaller brains than humans: I wouldn’t be surprised if T-Rex was capable of either tactic. So the cranial vascular system may not be the limiting factor here.

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[QUOTE=Fear Itself]
According to the requirements laid out by the OP, our fictional troll need not have the intellectual capacity of a modern human, only that it be capable of speeds enabling it to run down a human, or executing an ambush of a human. Many predators are capable of this, with much smaller brains than humans: I wouldn’t be surprised if T-Rex was capable of either tactic. So the cranial vascular system may not be the limiting factor here.
[/QUOTE]

Point taken, but we are still talking about a mammal, and a hominid to boot. I still don’t think it’s reasonable to make size assumptions based on an animal with such a distinct evolutionary background. And if the brain shrunk down to even close to dino size, I don’t think we could reasonable call such a creature a “hominid”. If we model the “troll” after known close relatives of humans, then Gigantopithecus is our best bet.

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[QUOTE=John Mace]
If we model the “troll” after known close relatives of humans, then Gigantopithecus is our best bet.
[/QUOTE]
I don’t see that we have to limit our speculation to known relatives of humans. Just because Gigantopithecus was the largest ape we have evidence of does not answer the OP question; how big could a being built on a human frame get and still function normally? Just because it didn’t happen in reality, doesn’t mean there is a physical reason apes never evolved to that size. There are many environmental and competition factors that determined the maximum size of real hominid, beyond the physical constraints of pumping blood and moving limbs. I interpreted the OP to be a question about what might be possible, not what already was, the largest hominid.

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[QUOTE=Fear Itself]
I don’t see that we have to limit our speculation to known relatives of humans. Just because Gigantopithecus was the largest ape we have evidence of does not answer the OP question; how big could a being built on a human frame get and still function normally? Just because it didn’t happen in reality, doesn’t mean there is a physical reason apes never evolved to that size.
[/QUOTE]
I believe John Mace’s point is that a biped with a vastly smaller brain (and presumably correspondingly lower intelligence) couldn’t really be classified as a hominid (members of family Hominidae), as one of the key characteristics of Hominidae are their comparatively ginormous brains and the accompanying nutritional requirements. (It’s also unclear biologically how you’d scale up a hominid by a factor of two or more but keep the brain the same size as a human–this would presumably require somehow degrading major cognitive capabilities without interfering with critical autonomous functions.)

As a practial matter, the great apes (man included) owe a significant amount of their success to their sizeable brains and resultant behavioral adaptability. (The same could be said for other omnivorous mammals in similar ecological niches, specifically bears.) Removing this would make other adaptations, such as grasping opposable thumbs, advanced color vision, and possibly upright posture, less or negligable in value. Adaptation isn’t a matter of tuning one key characteristics toward a particular goal, but rather directing an orchastra of phenotypes toward general reproductive success. So, taking issue with the necessity of blood flow to a proportionally enlarged brain isn’t entirely out of the context.

Stranger

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While I would prefer to keep my “Trolls” bipedal, I’m not opposed to a semi quadrapedal lifestyle. The main focus should be to create the best combination of characteristics that we could find in an large, human-like creature. They may be ape-like in body, but must have a rudimentary intelligence. The lion’s share of folklore attributes them capable of speech and basic cunning. I’d rather not lose that if it’s possible.

The vast majority of this speculation is to allow me to create resonable physical interactions between my characters. I have a great dislike for fantasy that prefers to have it’s physics both ways. For example, a 30 m dragon that is simultaneously light enough to fly, and yet durable and strong enough to tear down stone buildings. :dubious: This kind of thing interrupts my reading.

I don’t mind taking minor liberties in order to write a better story, but I DO feel that all events should be physically possible, however improbable. Knowing a reasonable physical description and functions of a scientifically accurate being allows me a greater amount of freedom with my writing; and forces creative solutions upon my characters.

Keep the speculations coming! :cool:

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Well, we know there were bipedal hominids that had much smaller brains than humans. Take a look at this wikipedia entry for robust Australopithecenes, which apparently the current fashion is to dub Paranthropus. However, these guys weren’t larger than H. sapiens.

And note that these guys almost certainly had a much more vegetarian diet than the lineage that led to Homo, so wouldn’t be good candidates for ravenous man-eaters.

But gigantic bipedal hominids with a taste for meat certainly aren’t physically impossible, but once you get past 3 meters tall the scale issues go farther and farther out of control. It’s hard to imagine how a 4 meter tall hominid could do much of anything, whereas a 3 meter hominid is roughly twice as strong for it’s size.

So if you want meat-eaters, they aren’t going to have Paranthropus style skulls and teeth, but rather Homo style skulls and teeth. That doesn’t mean they need giant brains relative to their size ala H. sapiens or H. neandertalensis, they could have Homo habilis or erectus size brains.

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[QUOTE=Lemur866]

But gigantic bipedal hominids with a taste for meat certainly aren’t physically impossible, but once you get past 3 meters tall the scale issues go farther and farther out of control. It’s hard to imagine how a 4 meter tall hominid could do much of anything, whereas a 3 meter hominid is roughly twice as strong for it’s size.

[/QUOTE]

I rather like this idea. Let us consider then a 3m bipedal hominid, with an intelligence level around, but below, that of neanderthal.

I imagine such a creature might make primitive clothes if it needs them, (it’s great size and a fatty layer might well insulate them enough to do without) and command a simple language.

From what has been stated above, our H. Trollensis(tm.) :wink: will have massive thick legs, and an accompannyingly heavy skeleton. Due to their cold environs it is not a stretch to imagine that they might sport a fat layer, and might be rather hairy.

I don’t see them as running down their prey often, but probably rely on sneak attacks; using their massive weight and strength to disable and kill their meals. They might employ primitive weapons such as hammerstones and stone hand axes. I also imagine that they are slow to mature and reproduce, their large caloric needs keeping them from forming large family units. This semi solitary existance should also keep their numbers in check.

As envisioned above, H. Trollensis would be a fairly formidable ambush hunter. A quick burst of speed should bring it within range of it’s prey. Once there, I imagine it might well break or dislocate a limb, then bringing it’s weight and stregth into play to basically bludgeon it’s target to death. Given the strength of such a being it should be able to butcher and carry off most prey items with little difficulty. A wary man should be able to outrun H. Trollensis over a distance. I should think that a mounted, armed human would be a fair match for such a creature. An unmounted, armed man would have an advantage of intelligence and dexterity, but without firearms might well become easy prey to a sufficiently motivated Troll.

All said, how efficient might traditional weapons fare against a Troll?

What would the general strength of a 3m hominid be in layman’s terms?

What might be the line between easy prey and that which would give H. Trollensis pause before trying to stuff it’s gob?
Thanks again for all the help and a fascinating mental excersise!

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[QUOTE=Acid Lamp]
our H. Trollensis(tm.) :wink:
[/QUOTE]

Homo trollimorphus would be better; trollimorphus = with a troll-like form. The ending -ensis means “living in” or “from,” as in H. neanderthalensis. (And note the genus is capitalized, but the species name is not.)

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I dunno. I don’t think that the neaderthal peoples were dumb by any means. What is wrong with mainly herbivore type folks?