Chapter 6, Bigfoot in Evolutionary Perspective: The Hidden Life of a North American Hominin

Chapter 6

Bigfoot and Gigantopithecus: Near Opposites

Having established the general ecological niche of bigfoot as an omnivore with strong predatory leanings, as well as some of its basic abilities, especially its ability to move suddenly and quickly through the most challenging of terrain, whether it be top end running speeds in the thirty-five to forty mile per hour range or the ability to make standing horizontal leaps or vertical jumps of great distance, whose equal as a predator, in terms of size, speed, agility, and strength might only be rivaled by the African lion or the Asian tiger, it’s imperative to understand exactly how Gigantopithecus lived in its day and what ecological niche it occupied to determine if it is the probable ancestor of bigfoot as suggested by the majority of bigfoot researchers and enthusiasts. The most glaring similarity that Gigantopithecus and bigfoot share is their startling size, with some adult sasquatches attaining heights of eight feet and correspondingly robust builds to match. A close range encounter with a bigfoot can be overwhelming for an eyewitness for a variety of reasons, especially the extreme contrast between the eyewitness’s height and weight in relation to the bigfoot, which can provoke feelings of vulnerability as well as awe—no one has ever looked down on us from a height of eight feet before—exacerbated all the more by the lack of a previously existing frame of reference to help the eyewitness put the experience in any type of logical perspective. Remember the response of the truck driver who saw a bigfoot wade out of the Ohio river? “I can’t describe it. I’ve never seen anything like it before.”[1] In fact, the encounter defies accepted scientific logic in all aspects, embodied first and foremost by this giant manlike or apelike upright walking cousin that shouldn’t be there and which lends a surreal element to the encounter.

The initial encounters between Gigantopithecus, over ten feet tall when standing on its hind legs and weighing up to 1,200 pounds, and Homo erectus thousands of years ago likely produced similar astonishment in erectus, as Cinchon, Olsen, and James (1990) suggest. I imagine though that much of this astonishment eventually faded as Gigantopithecus took its place among the other animals the newly migrated Homo erectus became familiarized with in its southern Asian environment over a rather short period of time, likely within a generation. Certainly, there must have remained an awe and respect for any creature so large and which possessed traits so similar to their own, but its sheer size likely doomed it as Homo erectus found Gigantopithecus to be a meat bonanza that could feed the entire clan for as long as the carcass lasted before the meat rotted. With its stone and bamboo tools and coordinated hunting methods, erectus likely had the ability to bring down this behemoth of an ape, possibly targeting smaller females or juveniles while isolating them from the protection of a larger male. Perhaps even thousands of years ago, such a kill, and the ability to bring down a giant, brought a certain esteem to the successful hunters, testifying to their courage and hunting prowess, likely making Gigantopithecus even more highly prized—and highly targeted—as both prey and conquered foe. And for all its similarities to the manlike form, Gigantopithecus differed in one substantial aspect. It was almost assuredly a quadruped. It walked on four legs, much like its closest living relative, the orangutan. Did this somehow distinguish it in the mind of erectus? Would this make it a lot less awe inspiring than the human-bigfoot encounter? Place Gigantopithecus alongside all the other four-legged animals in the world with which erectus was familiar in a rather matter-of-fact way? A potential meal first and foremost? Perhaps an animal to be avoided because of its power and strength? We can’t know the mind of erectus and what form of higher thought and emotion it had, and some anthropologists classify it as little more than an animal itself due to its smaller brain capacity. Still, erectus must have been very much at home in its world, and distinguished among its many forms, animal among them, including Giganto, and had them well-classified, enough to know which forms best suited its particular needs and from which forms threats to its safety arose.

While it is open to speculation whether erectus hunted Giganto outright or simply upset the ecological balance with its migration into Asia in ways that led to the demise and eventual extinction of Giganto, since there does seem to be a correlation (Cinchon, et al, 1990), what can’t be disputed is that Giganto, being primarily herbivorous and having evolved to such a size that it had little to fear from predators, would have been largely indifferent to the initial presence of erectus, perhaps just slinking back into the jungle forest if disturbed, though it may have come to fear erectus if it was actively hunted. Unless provoked or disturbed, Giganto posed no threat to Homo erectus. It’s business was eating and digesting tough fibrous plant foods, some fruits, with bamboo a likely dietary mainstay, which is further suggested by a pattern of tooth decay that resembles that of the giant panda, itself a specialized eater of bamboo (Cinchon, et al, 1990). While skeletal remains of Giganto have not been unearthed, teeth and jaw fragments clearly indicate that it was a chewing and grinding specialist. Except for the extreme size of the molars, which make the molar teeth of the gorilla look small, there is a certain uniformity to its teeth. They are blunt, flat surfaced, including the canines to a degree, especially adapted to chewing tough fibrous plant foods. Absent are the ripping and tearing teeth that are the mark of the predator. Even the male gorilla, already shown to be a chewing and grinding specialist, is characterized by large canines, which can be used in shows of display or for defense. In contrast, Gigantopithecus can be classified as even more specialized. “The premolars are molarized: that is they have become broad and flattened, and thus resemble molars” (Cinchon, et al, 1990). So too, the canines of Giganto were reshaped over thousands of years so that they are nothing like the long pointed canines of the male gorilla. They are more akin to premolars (Cinchon, et al, 1990). With a more limited ripping ability, they are somewhat akin to an additional four grinding teeth, almost as if they were recruited to help with the chewing workload, though what it really amounted to was that those individuals that inherited flatter canines were conferred a genetic advantage in that they were able to grind, chew, and process more fibrous plant foods and reap additional energy as a result, important for any animal, especially one the size of Giganto, and this beneficial mutation spread through the population.

A hallmark of Giganto would have been an exceptionally large digestive tract. The bulky, low nutritious plant foods it was eating demanded it. A pot-bellied appearance similar to the gorilla, so especially evident when the gorilla is in a sitting position, is also a logical assumption for Gigantopithecus. Its massive size was only a requisite for a proportionately larger gut. Cinchon, et al, (1990) point out that in herbivores the small intestine alone is fifteen to twenty-five times the body length, while in carnivores it is only four to eight times body length. That equates to a small intestine anywhere from 150 to 250 feet long for Giganto and this cannot simply be hidden in a larger body frame to give a slim or small-waisted or even flat stomached appearance. A conical ribcage like that of the australopithecines and the gorilla is also a near certain trait for Gigantopithecus, which would also contribute to the appearance of a protruding midsection and lack of a waist. Such a ribcage is a trait of hominoids characterized by plant eating and correspondingly large digestive tracts, which contrast the barrel shaped chests of all hominins starting with Homo erectus and exemplified by smaller intestines, smaller waists, a marked tendency toward meat eating, and lungs capable of meeting the rigorous demands of distance running and prolonged activity.

To balance the extreme energy demands of the large gastrointestinal tract, a smaller, less energetically expensive smaller brain is implied, which is further supported by Giganto’s primarily herbivorous diet of low quality foodstuffs eaten in huge quantities, a diet incongruous with an energy taxing large brain. Its massive jaws further imply a large sagittal crest to anchor huge jaw muscles. These traits are all evolutionary compliments of one another. Where one exists, it is logical to look for another, and even in the absence of skeletal remains these traits are strongly implied by Gigantopithecus’ oversized molars alone. The tropical forest habitat of Asia in which it dwelled—and to which it was restricted—is indicative of an ape that was reliant on fast growing vegetation that could recover quickly when an animal of its extreme size denuded an area of vegetation, which further points to bamboo being its dietary mainstay. The flora of the northern temperate zones offered neither the quick recovery abilities nor the sheer biomass necessary to support a troop of these giant apes. While its large body size could have insulated it from the cold and a foray of a few days north could have been theoretically possible, a predominately coniferous forest meant gradual starvation for these apes. Their range was thousands of miles short of the Bering land bridge for sound ecological reasons, and if it was hunted by Homo erectus, which in turn was restricted to the tropics and subtropics, this restricted range would have contributed to Giganto’s extinction.

For our purposes, picturing Gigantopithecus as an outsized gorilla will suffice and is not far removed from the truth anyway. Its eating habits and activity levels—or lack thereof—were simply of magnitudes greater than the gorilla. As much as the gorilla eats, Gigantopithecus ate far more. As much chewing and grinding of tough plant matter as the gorilla engages in, Gigantopithecus was chewing and grinding even more, and its days were idled away in this fashion. When not eating, weighed down by the sheer bulk of what it had eaten, it conserved energy by resting and letting its prodigious gut digest and digest some more (Cinchon, et al, (1990). These apes were not characterized by great outbursts of activity—just the opposite, and at times, a kind of digestive stupor. More intensive or extended movements by these apes consisted of ambling from one plant food resource to another, likely bamboo, which was abundant and not difficult to find in the Asian tropics. Without fear of predation, Gigantopithecus was governed by an economy of movement, which their massive body size demanded in order to conserve energy. Cinchon, et al, (1990) sum it up like this:

“Thus we may state almost without any doubt that Gigantopithecus was a slow, deliberately moving creature. To our eyes it probably would have had a phlegmatic, clumsy, perhaps even comical appearance. It passed its days stuffing its face, most likely using its huge hands in the same way an elephant uses its trunk—to shovel down food in bulk. Time not spent eating was devoted to resting and sleeping. Nothing about Gigantopithecus would have reminded us of an acrobatic monkey or a playful chimpanzee.”

In addition to this, a band of Gigantopithecus would probably not have been all that difficult to find. Dung droppings and newly denuded swaths of vegetation would have been evidence of the bands passing, perhaps even resembling something of a path that led right up to them in extreme instances. Giganto was likely a noisy eater, reaching for and constantly breaking bamboo and other foliage before chomping and grinding it down. The band may have even been quite vocal as it need not fear attracting predators. Even if Gigantopithecus was more solitary in nature or traveled in smaller family units, much of this reasoning still likely applies. Males might very well have a tendency toward long calls in this scenario, which would give their locations away. With a newly arrived predator on the scene in the form of Homo erectus, and a rather hungry one at that, the mystery of this slow moving, easily located great ape’s extinction—the only great ape to ever have gone extinct—hardly seems so elusive anymore.

Size alone is a poor correlate when trying to determine taxonomic relationships and because of its size Giganto has become something of a red herring in the field of bigfoot research. The ancestors of Gigantopithecus were smaller apes and tracing its lineage even farther back, to the time its ancestors were almost exclusively tree dwelling, would reveal yet smaller arboreal apes. Large mammals, some of which can be classified as megafauna, evolve from smaller ancestors for a variety of reasons, the most obvious being that former predators at some point over the course of millions of years wind up relatively small in comparison. They can no longer prey upon such an oversized mammal. Size almost exclusively becomes the oversized animal’s defense and it’s highly effective, which is why evolutionary history is smattered with large animals that evolved from smaller predecessors, animals just like Giganto. No one in any scientific field suggests that in order to explain Gigantopithecus, a similarly sized ancestor or series of ancestors must be found; in fact, just the opposite, smaller ancestral forms are entirely expected. The parallel here is that the search for a bigfoot ancestor is not a search for a similarly sized or even larger ancestral form. It is a search for smaller bipeds.

Giganto was big and it was an ape, and that is where any similarities to bigfoot begin and end (see Table 6.1). While technically an omnivore, just as bigfoot is an omnivore, Giganto was primarily herbivorous while bigfoot is largely carnivorous. Giganto, while capable of intimidating displays, surely branch breaking or beating on its chest or against a tree, was for the most part very deliberate in its movements, which would have given it the appearance of an animal moving with caution. In general, such movements also characterize its closest living relative, the orangutan. Giganto wasn’t fast moving like bigfoot, wasn’t walking long distances, sometimes tens of miles each day on average in search of food and prey, and wasn’t capable of running thirty-five to forty miles per hour, and had no need to because the vegetation it ate was never far from its grasp. There were likely preferred or seasonal foods it sought out which required some trekking through the jungle, perhaps comparable to the one to two miles the gorilla sometimes treks when moving to a new food source, but once there Giganto remained for as long as the food supply lasted. The great bipedal running strides, jumps and leaps that are typical of the bigfoot were not in Giganto’s repertoire. And how could they since Giganto was a quadruped and relied on an altogether different mode of locomotion and anatomical dynamics? Whatever jumping it did would have required propelling itself from four legs. The chimpanzee is impressive in this regard, but we can’t expect the 1,200 pound Gigantopithecus with a belly full of pulpy vegetation to be anywhere near as capable. The areas Gigantopithecus could have rivaled bigfoot were in strength and size, though being a quadruped its strength would have manifested itself differently, the result of an altogether different center of gravity. Lifting the back ends of vehicles for an extended duration while standing on its hind legs may not have been in its repertoire, though smashing a fist down on a vehicle would be. These are just physical or physiological differences and speak to nothing of differences in the brain or community structure.

Table 6.1

Characterizing Bigfoot and Gigantopithecus

Bigfoot Gigantopithecus Similarity?


Bipedal Quadrupedal No
Omnivore, largely carnivorous Omnivore, almost exclusively herbivorous No
Persistence walker, runner, jumper, leaper, top speeds 35-40 mph Fist walker or knuckle walker, limited bursts of activity, limited endurance and speed No
Fast, agile movements Slower, deliberate movements No
Range extensive in one day, up to 10, 20, 30+ miles when on the move. Range localized in one day, probably similar to the gorilla, 1-2+ miles when on the move. No
Exceptional size Exceptional size Yes
Inhuman strength Inhuman strength Yes

Studying Giganto, or other quadrupedal apes for that matter, in order to gleam insights into bigfoot leaves bigfoot forever a mystery when this need not be the case. There are few correlates between Giganto and bigfoot, at least no more correlation than between bigfoot and the gorilla, and the common ancestor of the gorilla and bigfoot would be closer genetically to bigfoot than the common ancestor of Gigantopithecus and bigfoot. This same genetic truth holds true in our own case, which is why anthropologists aren’t studying Giganto to gain insights into the evolutionary past of Homo sapiens. We last shared a common ancestor with Giganto approximately fourteen million years ago, well before our bipedal ancestors—and the bipedal ancestors of bigfoot—arose some five to six million years ago. Gigantopithecus does tell us that apes were capable of evolving into extreme sizes, which at least removes this criticism from the arsenal of bigfoot skeptics, though variation within our own species in the form of the extreme minority of men who attain a height of seven feet does this as well.

There is no evidence for Giganto being bipedal and no reason to deviate from scientific consensus that it was a fist walking or knuckle walking quadruped like any terrestrial ape. And for it to evolve into a biped would mean a complete reshaping of its body, the equivalent of an evolutionary overhaul—a newly vertically aligned foramen magnum, an ‘S’ shaped spine, a broader pelvis, a reshaped gluteus maximus, a femur angled inward, and a non-divergent big toe for starters. It means changing an animal with a spine that is aligned horizontally into an animal with a spine that is aligned vertically. These changes are so profound, akin to remaking a horizontal bridge into a vertical skyscraper,[2] that there is good reason that bipedalism arose once—and once only—in hominoid history. The evolutionary odds were against it. The fossil record is testimony to the extremely rare event it was. All hominins can retrace their roots to a single bipedal ancestor. Our history is not the history of several different bipedal apes arising convergently or in parallel or in tandem. Instead, it is the history of later forms radiating from one single early form. As complicated as hominin evolution is, it is rather tidy in this regard. Once the fossil of a bipedal ape is unearthed, the question of greatest immediacy is whether it is a direct ancestor of Homo sapiens or a close evolutionary cousin? Did it arise four million years ago? Three million years ago? Two million years ago? Five hundred thousand years ago? These time frames are but blips in the greater scale that life has existed on earth and speak to the close relations of the hominin lineage. Bigfoot belongs in this lineage. In structure and body form it meets every criteria, bipedality first and foremost. Any morphological differences—and there are far more similarities than differences—can be explained by evolution and the differentiation of species. There is no reason to assume bigfoot is an exception to sound anthropological principals, somehow a case of convergent evolution, much less that Gigantopithecus, in many ways bigfoot’s direct opposite, somehow gave rise to it. As Craig Stanford (2003) states, “Bipedalism is such a rare suite of traits in the animal kingdom, that it would evolve twice independently in the same lineage is as about as likely as lightning striking your house two times.” Yet bigfoot bipedalism having arisen through an incident of convergent evolution in some other unknown ape at some other unknown time in the hominoid lineage has been a favored—almost prized—scenario of those few academics willing to give serious thought and study to bigfoot.

There is another indirect piece of evidence that Gigantopithecus wasn’t bipedal. There are no bipedal forms radiating from it in the fossil record as would be expected if the hominin lineage is any indication. And since Asia, not Africa, was initially thought to be the cradle of humanity, it was, almost exclusively, the focus of anthropological excavations of the early twentieth century and can hardly be characterized as unexplored. By and large, it is Homo erectus fossils that are unearthed in this part of the world.

Since bigfoot is not our evolutionary ancestor, the next immediate question that arises is how close an evolutionary cousin is it? When did humans and bigfoot last share a common ancestor? If bigfoot is to explained—and understood—this question needs to be examined.

[1] incident #991281

[2] This allusion has been made before. I am unsure who made it originally.


Ciochon, R. L., Olsen, J. W., & James, J. (1990). Other origins: The search for the giant ape in human prehistory. New York, NY: Bantam Books.

Stanford, C. B. (2003). Upright: The evolutionary key to becoming human. Boston, MA: Houghton Mifflin Company.

Copyright 2015, 2016-20 T. A. Wilson. All Rights Reserved.

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