In the order of primates – more than 500 species, distributed in 79 genera and 16 families – there is a wide range of weights and sizes: from 30 grams of the pygmy lemur (Microcebus myoxinus) to the more than 150 kilos of male eastern lowland gorillas (Gorilla beringei graueri).
But this range was even greater in the past. Specifically, the mass of some subfossil land lemurs from Madagascar, which disappeared in historical times after the arrival of humans to this island, could have exceeded 200 kg. It is the case of Archaeoindris fontoynontii.
The record, however, is held by the extinct Asian ape Gigantopithecus blacki, with an estimated height of around three meters and an estimated body mass of up to 300 kg.
A slim trace
Despite its notable dimensions, the fossil record of Gigantopithecus It is quite meager: only four relatively complete jaws and around 2,000 isolated teeth are known. In fact, no bone belonging to its postcranial skeleton has yet been found, despite almost nine decades of fruitless searching. This makes it difficult to accurately estimate their postural habits and body dimensions. The reason is that although the size of the teeth is related to that of the body, the dimensions of the teeth also depend on the type of diet.
The initial discovery of Gigantopithecus It occurred in a Hong Kong pharmacy, where German anthropologist Gustav Heinrich Ralph von Koenigswald discovered fossils that were sold as “dragon teeth.” These specimens, as occurred with the teeth of Homo erectus and other very relevant fossils, were traditionally used in the Chinese pharmacopoeia for their supposed medicinal properties, in powder form.
The discovery led to an intensive, although unfruitful, search for fossils of the extinct species, which led to the discovery of 22 caves with preserved remains. in situ. These deposits are located in two areas of Guangxi province, in southern China: Chongzuo and the Bubing basin.
Conscientious examination of fossils
The work that concerns us now has just been published in the magazine Nature. It analyzes a good part of the fossils available from Gigantopithecus blacki, as well as those of a contemporary species of orangutan that is also extinct, I put weidenreichi, whose body mass was 20% greater than that of today’s orangutan.
Researchers have dated the fossils and the sedimentary deposits of the karst cavities (caves) that contain them using six different radiometric techniques; among them, two variants of the luminescence method, the spin resonance and the uranium series.
They have also carried out microstratigraphic studies and have analyzed fossil pollen, remains of carbon preserved in the sediment and the abundance of stable isotopes (that is, variants of the same chemical element that have different atomic masses). Finally, they have examined the microwear patterns of the occlusal surface of the teeth of Gigantopithecus blacki and of I put weidenreichi, to obtain clues about the diet of both species.
Gigantopithecus runs out of trees
The 157 age estimates obtained for the 22 cavities that have been studied cover a wide chronological range, between 2.3 million and 49,000 years ago. In the case of Gigantopithecus blacki, These data allow us to place their disappearance in a time range of between 295,000 and 215,000 years ago. Pollen analyzes show that, prior to this interval, the predominant vegetation of the territory inhabited by Gigantopithecus It was composed of tree species of the families Pinaceae (firs, cedars and pines), Fagaceae (chestnut, beech and oak) and Betulaceae (birch, alder and hazel).
In the time period immediately prior to the extinction of Gigantopithecus This vegetation is replaced by tree species typical of a more open environment, then giving way to a clear predominance of ferns and grasslands. There is also an increase in charcoal in the sediment, which suggests an increase in the frequency of forest fires. All this indicates a profound change in the ecosystem, marked by progressive aridification and a more seasonal climate.
Analyzes of fossils provide more relevant information. Thus, the stable isotopes of carbon and oxygen (whose frequencies are related to the vegetation on which both ape species fed and to their water sources, respectively) hardly change over time in the orangutan, but they do in the case of Gigantopithecus blacki. The reduction of wooded areas forced a change in their diet, until then based mainly on fruits.
Likewise, dental microwear studies do not indicate temporal variations in the diet of I put weidenreichi. Instead, Gigantopithecus blacki he would have changed his diet towards a menu based on more abrasive and less succulent plant resources. This was accompanied by an increase in the dimensions of the giant ape’s dentition and, possibly, also by a decrease in its population, as suggested by the lower abundance of fossil teeth in these chronologies.
Extinct due to starvation
In short, the study points out that the extinction of Gigantopithecus blacki, adapted to dense forests with permanent foliage, was produced by an increase in environmental variability and seasonality of climate. As a result, this giant ape would have been forced to consume a smaller variety of plant products, which also provided less nutritional value. This is shown by the analysis of the more marked growth bands in the enamel of fossil teeth.
Such conditions would have been less stressful for the orangutan, as it is a less specialized species than Gigantopithecus. Its smaller size and more arboreal habits possibly allowed it to move more easily.
On the other hand, the voluminous body of Gigantopithecus, Their lower mobility and longer generational turnover times probably sealed their fate. The only testimony to its presence is its large fossilized teeth, probably the ones that fueled the legend of the yeti in Asia.