OntarioSasquatch

  ... continued
The Ape That Was
Asian fossils reveal humanity's giant cousin
by Russell L. Ciochon

 A more direct line of evidence that could be pursued regarding the diet of Gigantopithecus was pointed out to me by Bob Thompson, a graduate student in New World archeology, who attended one of my lectures about the extinct ape. He suggested we might look at the teeth for adhering phytoliths, microscopic pieces of silica found in many plants. The existence of phytoliths has been known since the early nineteenth century, and scientists had already successfully looked for them on stone tools, to which they apparently bond physically by the combined action of friction and moisture. But it was the first time, as far as I know, that anyone had suggested looking for them on fossil teeth.
  Four teeth were borrowed for study from the British Museum (Natural History) and the Senckenberg Natural History Museum in Frankfurt: an upper incisor, lower canine, lower premolar, and lower molar. After the teeth were cleaned to insure that what we found was definitely part of the fossils, they were examined under a scanning electron microscope at the University of Iowa by Smithsonian paleoecologist Dolores Piperno. At least thirty phytoliths were found on the teeth, most of them on the molar. We also detected tiny scratches apparently left by phytoliths, which are harder than tooth enamel. In one case, we found a phytolith sitting astride the end of the track it had plowed into the tooth - like a sled stopped in its path in the snow.

A photomicrograph shows a silica fragment bonded to a tooth of the fossil ape.
Its shape indicates that it came from grass, possibly bamboo. Color enhancing
isolated the silicified mass of plant cells and, within it, the impression of a
single cell.
 

 More than half of the phytoliths we observed were long and needlelike and could be attributed to the vegetative part of grasses, possibly bamboo. The rest were conical or hat shaped, attributable to the fruits and seeds of dicotyledons. Piperno tentatively identified them as fruits from a tree of the family Moraceae, quite possibly durian or jackfruit, both of which are common throughout tropical Southeast Asia. This proved that Gigantopithecus had a varied diet, although we still suspect that bamboo was its staple food.

What other conclusions can be drawn about the extinct ape? An outstanding characteristic of giant herbivores is their extreme slowness. They have no particular need of speed: their size and thick skins protect them from predators, and of course their feeding habits require no more of them than that they move from place to place as they systematically denude the landscape of vegetation. Furthermore, they are usually stuffed full of bulky food to digest, which tends to produce inertia. Gigantopithecus probably followed this pattern.

Finally, the adult males of the giant ape were much larger than the females. Australian anatomist Charles Oxnard statistically analyzed 735 teeth of Gigantopithecus that were complete enough to be measured accurately. He found that they divided neatly into two size groups of equal number, which he interpreted to represent the males and females in the population. The contrast was greater than that seen in any living primate species, including the gorilla and the orangutan, two species in which the male is substantially bigger than the female. In Gigantopithecus, the difference in tooth size between the sexes may represent strong competition among males for mates - a clue to the species' social behavior.

The largest of the jaws, along with some of the teeth, are compared at with modern human remains.

To gain a more complete image of what the giant ape looked like, we sought the help of Bill Munns, who creates highly realistic, life-size models of existing endangered primates - gorillas, orangutans, and the Chinese golden monkey - for zoos and educational institutions. Based on the jaws and teeth, and using the proportions of the skulls of existing great apes, we estimated that the average male Gigantopithecus had a skull that measured eighteen inches from the bottom of the jaw to the highest point of the sagittal crest (a male gorilla, for comparison, has a skull ten inches high).

The next step was to project a hypothetical skeleton from the hypothetical skull. For this purpose Munns used as references two of the largest terrestrial primates known: one modern, the gorilla, and one from the fossil record, the extinct giant baboon Theropithecus oswaldi. In determining the size of Gigantopithecus, we felt it necessary to scale the body back a bit, so as not to be influenced too much by the giant ape's extraordinarily deep and thickened mandible. Nevertheless, given that the average male silverback gorilla is about six feet tall (standing erect) and weighs in at 400 pounds, Munns calculated that the average Gigantopithecus male was more than ten feet tall and weighed as much as 1,200 pounds - comparable to a large male polar bear.

Bill Munns stands next to his model of a Gigantopithecus male,
a quadrupedal, fist-walking creature that also could have
stood erect, as bears do.

 One intriguing question is what contact our remote ancestor, Homo erectus, may have had with the giant ape. That the two coexisted for some time in the same region is supported by direct evidence. In 1965, Vietnamese paleontologists discovered the remains of both creatures at Tham Khuyen, a cave site in Lang Son Province, near the Chinese border. Chinese excavators followed suit, excavating Gigantopithecus and Homo erectus side by side in Hubei Province in 1970 and more recently, in 1987, in Sichuan Province.

Gigantopithecus was native to southern Asia, while Homo originated in Africa about 1.6 million years ago and migrated eastward, finally arriving in what is now Southeast Asia about one million years ago. The opportunity to explore this nexus attracted archeologist John Olsen and me to Vietnam. One reason we did not choose to go to China was that all the promising sites had been reserved by Chinese paleoanthropologists, and we doubted we would find a new site in a region that had been so thoroughly mined. In contrast, Vietnam had no history of exploiting fossil-rich caves for dragon bones. And so in January 1989 we found ourselves probing four caves at the base of a karst tower near the hamlet of Lang Trang, about 100 miles southwest of Hanoi, as part of a joint American-Vietnamese expedition.

The caves had seemed promising in our preliminary survey the previous May, and as we began work, even local children brought us fossil mammal teeth (although we tried to discourage them), which they retrieved from an underground stream by squeezing through a crevice in the cave we called Lang Trang I. Meanwhile, we began cutting out blocks of breccia, the sediment typical of caves, which is gradually formed by material washed or otherwise transported into a cave and cemented with limestone dissolved from the cave walls and ceiling.

The fourth day of our dig, Friday the thirteenth, turned out to be a lucky one: within the main deposit I found a lens-shaped vein of dark, sandy sediment that was unusually rich in fossils. The material had probably washed into the cave from the nearby Ma River, which in ancient times meandered right alongside the karst tower. Perhaps a violent monsoon had caused the river to overflow its banks and flood the cave. After the waters receded, the slow process of breccia formation began again, sealing the sandy lens within Lang Trang I.

We immediately set to work cutting out hunks of the sandy deposit, revealing a small chamber that we surmised was the source of all the fossils the children had been bringing us. Our finds included barking deer, a musk deer the size of a big dog; sambar, a large deer with three-pointed antlers; wild boar; and giant panda. A huge, ridged molar, weighing several pounds and belonging to Stegodon, an extinct relative of the elephant, assured us that we were dealing with a Pleistocene site that might also contain Homo erectus and Gigantopithecus. One softball-sized sample of this deposit was later analyzed at the University of Iowa, revealing that it also contained some small teeth and fragmentary limb bones of a diverse microfauna, including rodents, reptiles, fishes, and riverine sponges. These fossil fragments were about the same size as the coarse sand particles they were mixed with.

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This article is reprinted from the University of Iowa website: http://www.uiowa.edu/~bioanth/giganto.html

Reprinted under the Fair Use Doctrine of International Copyright Law as educational material without benefit of financial gain.