The large teeth of a creature that would become known as Gigantopithecus were first encountered by science in 1935 after several were purchased from a Hong Kong drugstore.  Those teeth -- without any other parts of the skeleton -- were interpreted by physical anthropologists working in Asia as the remains of a huge creature.  While there were differing opinions as to whether the teeth had belonged to gigantic apes or gigantic humans, Ralph von Koenigswald, Franz Weidenreich, and W. C. Pei all agreed that Gigantopithecus was enormous.  

Those large teeth still fuel discussions of what the anatomy of Gigantopithecus was like. Estimates of very large body size (1000 lbs . . . 1200 lbs . . . ) attract a quantity of attention from Bigfoot enthusiasts, Creationists, and other "fringe" theorists that far exceeds that paid to other fossil apes. But where do those estimates come from? As I discussed briefly in this post, all of our information about Gigantopithecus is based on isolated teeth and a handful of mandibles.  That's something to go on, but not a lot. The complicated nature of the relationships between body size and tooth size, problematic when the first teeth of Gigantopithecus were discovered in the 1930's, remains an analytical issue today.  

How do we go from tooth size to body size?  Very carefully. Stanley Garn and Arthur Lewis discussed the matter in a 1958 paper in American Anthropologist titled "Tooth-Size, Body-Size and 'Giant' Fossil Man:"  

    "On the basis of morphology and size together, Von Koenigswald decided that the Hong Kong and Sangiran teeth and jaw fragments came from “giant apes.” However, Weidenreich later concluded that both the 1935-1939 Hong Kong [Gigantopithecus] teeth and the 1939-1941 Sangiran [Meganthropus] tooth-jaw fossils were the remains of true men, though extraordinarily large men, from the early Sino-Malaysian fauna (Weidenreich 1945:123-24). Finally, in his recent article, W. C. Pei reverted to the idea of a giant anthropoid and estimated that the “giant” ape of Luntsai stood “some twelve feet” high (Pei 1957:836).
    What is the evidence that these three sets of finds, separated from each other by space and time, all came from gigantic beings? How convincing is the evidence that big teeth necessarily indicate extraordinary stature? Lacking the postcranial skeletons, direct proof of body size does not exist. What remains is such indirect proof as can be gleaned from tooth-size relationships in man and apes. “This” admitted Franz Weidenreich . . . “is a very ticklish question. . . "

The question is "ticklish" because of the fact that tooth size, in addition to being related to body size, is also related to things like diet.  Similar-sized animals that eat different things emphasize different teeth. Animals that have to grind a lot of tough plant food tend to have cheek teeth (molars and premolars) with large grinding surfaces.  Animals whose diet consists of softer foods (like fruits) or involves lots of cutting and tearing (as in carnivores) typically don't have large chewing teeth relative to their body size because they don't need them (they're not selected for).

At the time Weidenreich wrote his 1945 monograph "Giant Early Man from Java and South China," the known fossil remains of Gigantopithecus consisted of just three teeth. Weidenreich's detailed comparative analysis of those teeth convinced him that Gigantopithecus was a hominid and a human ancestor. His discussion of the possible size of Gigantopithecus, while following from that conclusion, was cautious (pg. 111):

'In Gigantopithecus the length of the lower molar row is only twice that of modern man, not eight times, as in the lemur example. When the dimensions for the femur are calculated on the basis of the lemur ratio for the femur and the hominid ratio for the length of the molar row, the Gigantopithecus femur proves to be little longer than the femur of modern man and only slightly thicker. The same holds true for Meganthropus. Therefore, we can dismiss the body dimensions of the giant hominids, Gigantopithecus and Meganthropus, with the very general statement that they must have had large, heavy, and massive skulls, large strong trunks, but only slightly longer and stronger leg bones. No more precise statement can be made." 

Weidenreich died in 1948 and never got to see the Gigantopithecus mandibles that were discovered in the late 1950's. Consideration of those mandibles (and the growing number of isolated teeth available for study), led Elwyn Simons and Peter Ettel to argue in a 1970 article in Scientific American that Gigantopithecus was a large, herbivorous ape weighing as much as 600 lbs (272 kg) and standing about 9' (2.7 m) tall when upright. Simons and Ettel reconstructed Gigantopithecus with a posture and body plan like a gorilla. The body size estimate of Simons and Ettel was somewhat informal, based on a general appraisal of the size of jaw and assuming ​a proportional relationship between jaw size and body size.  

The 1980's saw the publication of studies that considered the allometry of tooth/body size relationships across primate taxa. A 1982 paper by Philip Gingerich et al. ("Allometric Scaling in the Dentition of Primates and Prediction of Body Weight From Tooth Size in Fossils") considered how tooth area scales to body weight among extant primates and used that information to estimate the weight of fossil primates. I have reproduced the figure from their paper that shows the logarithmic relationship and the regression formula based on that relationship.

While there is a general, positive relationship between tooth area and body weight among extant primates (which is a good thing for those of us interested in fossils), Gingerich et al.'s (1982) analysis makes it clear that there's a lot more going on than a simple, direct relationship.  What part of the relationship is based on geometry (bigger teeth as a result of bigger bodies) and what part is based on dietary adaptations (tooth size related to diet)? Good question.  Gingerich et al. (1982:99) concluded that

"Much remains to be learned about allometric scaling of tooth size and body weight in the dentition of primates and other mammals.  Our results demonstrate that there is a coherent pattern of differences in scaling at different tooth positions across the whole range of generalized primates.  We have not investigated how this general pattern might change if primates were subdivided into smaller taxonomic groups or into dietary guilds." 

As far as I can tell, that remains at least somewhat true today (I have yet to make a concerted effort to get into the current literature on tooth/body size scaling . . . hopefully I can get around to it soon).  Although we clearly know more about tooth/body size relationships than we used to, the estimation of primate body size from isolated teeth remains problematic.  While there are general relationships, they're not necessarily proportional. A big tooth doesn't necessarily mean a proportionally giant creature.

The large tooth from Denisova Cave is good example of how "big" is still equated with "giant" in the absence of other evidence.  According to this 2010 paper, the Denisovan tooth (probably a second molar) is the largest human tooth ever discovered. Because of its size (and because there aren't any other Denisovan fossils that can tell us something directly about body size), it has been interpreted by the fringe as evidence of giants (I wrote a little about it here). The tooth reportedly measures 13.1 mm by 14.7 mm, giving an area estimate of 192.5 square mm. Notably, it is smaller than the corresponding teeth of some austalopithecines (who were smaller in body size than humans but had a very tough diet, and, hence, big chewing teeth).  If I plug that area into the Gingerich et al. (1982) regression shown above (yes, I know it was based on areas of first molars, not second molars, but bear with me for the sake of general comparisons)  I get a body mass estimate of about 200 lbs (91 kg).  

Two hundred pounds: is that a giant? It's surely above average for humans today, but it's really a stretch to call a 200-lb individual a "giant."  Even allowing for that 200 lbs to be an underestimate (because it's based on a second molar rather than a first molar), how do we know that the the large tooth size isn't somehow related to the evolutionary history and/or diet of Denisovan populations? There are just a few teeth to go on - that's it. Just like with Gigantopithecus, I think we've really got to be aware that we're effectively blindfolded on the issue of body size until we've got some decent postcrania to look at.

As a final note, I think it's fascinating that Weidenreich saw the East and South Asian fossil record as supporting the idea that body size decrease through time was a major trend in human evolution. That is, of course, opposite of what the African record from the last 4 million years or so has now demonstrated. Weidenreich was wrong, but he was no lightweight and no dummy.  He based his ideas on the direct evidence that he had: fossils.  We'll never know what he what he would have thought of the decidedly un-human Gigantopithecus mandibles that were discovered just a few years after his death, but I would bet a large sum of money that he would not have stuck with the "giant phase of Man" idea that he outlined in his 1945 monograph.  Accepting that new evidence can falsify a hypotheses is part of doing science. 

Weidenreich's published ideas about also give the lie to the fringe/Creationist notion that 20th century academics have conspired and are continuing to conspire to suppress the "truth" about giants in the past. Or maybe someone just forgot to send Weidenreich his conspiracy brochure. I guess that's possible, since I have yet to receive mine, either.

Next up:  The history of body size estimates of Gigantopithecus.

References
​
Garn, Stanley M., and Arthur B. Lewis. 1958. Tooth-Size, Body-Size and “Giant” Fossil Man.  American Anthropologist 60(5):874-880.  

Gingerich, Philip D., B. Holly Smith, and Karen Rosenberg.  1982.  Allometric Scaling in the Dentition of Primates and Prediction of Body Weight From Tooth Size in Fossils.  American Journal of Physical Anthropology 58:81-100.
​
Simons, Elwyn L., and Peter C. Ettel. 1970. Gigantopithecus. Scientific American (January 1, 1970).

Weidenreich, Franz. 1945. Giant Early Man from Java and South China. Anthropological papers of the AMNH, Volume 40, Part 1.

I've occasionally been accused by those on the "fringe" side of being too hard on them and too easy on mainstream scholars and skeptics. I don't really think that's true. I think I call BS when I see it. I attribute the perception of unfairness to a couple of different factors.  First, I'm probably a little more careful about my choice of words when I'm discussing the work of those who are genuinely interested in answering a question or solving a problem (rather than just selling books). That's much more common among mainstream scholars.  Second, I think "fringe" theorists tend to be more sensitive to criticism because they're not used to having their ideas openly challenged on the basis of evidence.  Sometimes, unfortunately, scrutiny hurts their feelings. Third, some "fringe" theorists probably assume that I'm part of some wide-ranging conspiracy to suppress their ideas.

If I'm part of a conspiracy, I have yet to be told about it.  Maybe someday "they" will let me in on the secret and I can start writing blog posts on a laptop with a fully functional keyboard and a working battery, maybe even while not at home watching kids on evenings and weekends. Just think how effective I could be if I could work without also being responsible for wiping noses, stopping couch wrestling, and pretending to eat imaginary pasta.

​The fact is, professionals get things wrong also. Today's "whoops" comes from Paolo Viscardi, a natural history curator at the Grant Museum of Zoology in London.  This "Ask a Biologist" page includes Viscardi's answer to the question "Were there ever giant humans?, which includes the following:

​"Next I would say that there were Pleistocene apes called Gigantopithecus that stood about 10 feet tall. Their remains are very similar to those of humans, particularly when the skull is damaged. Mammoth and elephant skulls are also remarkably humanoid in appearance when they are damaged."

The appeal to the remains of Gigantopithecus is as unfortunate as it is wrong.

While there was a genus of ape (that we call Gigantopithecus) that existed in South and East Asia during the Pleistocene, we only know of these creatures through a few mandibles and teeth.  No-one has ever found a Gigantipthecus skull or any other part of the skeleton. Just teeth and mandibles. So how could we say the remains of a Gigantopithecus look like those of a giant human?  We can't, because we've never seen them.

The teeth and mandibles of Gigantopithecus are large.  Those teeth and mandibles form the sole basis of our estimates of body size. Big teeth and jaws mean a big primate, right?  Well, sort of. The problem is that there is a lot of variation among primates in the relationship between tooth size and body size (I touched on this subject in this post about why the original owner of the large Denisovan tooth wasn't necessarily a giant).  Tooth size alone doesn't necessarily tell us much because tooth size is related to diet. Relatively small-bodied australopithecines had large grinding teeth because they had a diet that included a lot of tough, low quality foods that needed to be heavily masticated.  The teeth and jaws of robust australopithecines (which were also small-bodied compared to modern humans) were even larger and were accompanied by a skull and chewing muscles that were clearly designed to produce and resist massive chewing forces.

So how do we estimate the body size of Gigantopithecus?  If you model the size relationship between teeth and body based on something like a gorilla (a primate with a relatively soft, fruit-based diet and small chewing teeth) you get a very large primate. If you use a model more like a robust australopithecine (a primate with a relatively tough diet and large chewing teeth), body size estimates are smaller.  Gigantopithecus was large, but I don't think we'll know how large until someone finds some postcranial bones. I'm sure they're out there somewhere. When I have the opportunity to talk about Gigantopithecus in my classes, I show pretty pictures of Liuzhou in China (image source) hoping they will inspire someone to go out and look.  Finding some Gigantopithecus bones other than teeth and jaws would be sweet.

Anyway, the figure of a 10' tall ape is repeated often. Maybe Gigantopithecus was that large, and maybe it wasn't. Bigfoot enthusiasts love a big Gigantopithecus, as do some advocates of the idea that humans have "degenerated" in size over time. There is zero evidence that Gigantopithecus is a human ancestor, and, in fact, we don't even know that it was a biped.  As with body size, ideas about whether Gigantopithecus walked upright on two legs are based on a few jaws and teeth. Anthropologist Grover Krantz's celebrated reconstruction of a Gigantopithecus skull, beloved by Bigfoot enthusiasts, was based on the same tooth and mandible fragments as all of our other interpretations. Krantz extrapolated a bipedal posture for Gigantopithecus based on the morphology of the mandible.  Not a lot to go on there, but I guess that doesn't matter much if you already know the answer. (See this post for more discussion.)

The academic imagineering was further amplified recently when Jeff Meldrum and Idaho State University produced a "full-size" skeleton of Bigfoot to help the History Channel create more schlock programming for its already crowded schedule of crap.  

"Meldrum borrowed from the physical looks of extinct animals such as the Gigantopithecus blacki — an ancient ape that was twice the size of apes today — and the Neanderthal — a species of human that is said to have became extinct 40,000 years ago."

So this "Bigfoot skeleton" is based partially on the "looks of extinct animals such as the Gigantopithethecus blacki"? Oh my.  If you've read this far, you know that we really don't know much about what those extinct animals actually did look like. We've got some teeth and mandibles - that's it. From those meager remains, wishful thinkers (including academics) have built up several real-looking reconstructions that will probably be cited for years to come as actual evidence. That's why Viscardi's statement ("Their remains are very similar to those of humans, particularly when the skull is damaged") is so unfortunate: he's reinforcing the incorrect notion that all of this business about the giant, bipedal Gigantopithecus is fact, established based on the existence of skeletons and skulls.

That's just not true.

Maybe Gigantopithecus was a 10' tall biped. But maybe it wasn't. What we don't know about Gigantopithecus far outweighs what we do know. That vacuum of knowledge is what allows all kinds of notions (not all of which can be correct) to survive. Some of those notions will be killed off when actual postcranial remains are found. In the meantime, I hope that academics will take care to convey to the public what we actually do and do not know about this creature.