Gigantopithecus blacki, the largest ever primate and one of the largest species of the southeast Asian megafauna, persisted in China from about 2 million years until the Middle Pleistocene when it became extinct. New research shows that from 2.3 million years ago the environment was a mosaic of forests and grasses, providing ideal conditions for thriving Gigantopithecus blacki populations. However, just before and during the extinction window between 295,000 and 215,000 years ago there was enhanced environmental variability from increased seasonality, which caused changes in plant communities and an increase in open forest environments. Although its close relative, the Chinese orangutan (Pongo weidenreichi), managed to adapt its dietary preferences and behavior to this variability, Gigantopithecus blacki showed signs of chronic stress and dwindling populations; ultimately, its struggle to adapt led to the extinction of the greatest primate to ever inhabit the Earth.
An artist’s impression of a group of Gigantopithecus blacki within a forest in southern China. Image credit: Garcia / Joannes-Boyau, Southern Cross University.
Gigantopithecus blacki is an extinct, giant hominid that once inhabited dense forests of Southeast Asia.
As the name suggests, the giant primate was larger than gorillas, standing up to 3 m (10 feet) and weighing up to 540 kg (1,200 lb).
“Our current understanding of Gigantopithecus blacki derives from Early to Middle Pleistocene cave deposits in southern China between the Yangtze River and the South China Sea,” said Professor Yingqi Zhang from the Institute of Vertebrate Palaeontology and Palaeoanthropology at the Chinese Academy of Sciences and colleagues.
“This primate is known for its unusually large molars, atypical enamel thickness, estimated body height of about 3 m and mass of 200-300 kg, making it the largest primate ever to have existed on Earth.”
“Despite 85 years of searching, the Gigantopithecus blacki fossil record is restricted to four mandibles and almost 2,000 isolated teeth with no postcranial evidence.”
“Its initial discovery in an apothecary shop in Hong Kong as a ‘Dragon tooth’ initiated a search for the first in situ finds and culminated in the discovery of several cave sites in two main areas, Chongzuo and Bubing Basin, in the Guangxi province.”
“These sites contain crucial evidence for its survival and eventual demise.”
“It’s a major feat to present a defined cause for the extinction of a species, but establishing the exact time when a species disappears from the fossil record gives us a target timeframe for an environmental reconstruction and behavior assessment,” said Macquarie University geochronologist Dr. Kira Westaway.
“Without robust dating, you are simply looking for clues in the wrong places.”
To identify the potential causes of Gigantopithecus blacki extinction, the researchers applied a regional approach to 22 caves in Chongzuo and Bubing Basin that contained either Gigantopithecus blacki-bearing or non-Gigantopithecus blacki-bearing cave deposits.
Using a combination of previous excavations and recently-discovered caves, they identified and sampled fossil breccias for dating, paleoclimate proxies and behavioral analyses.
Six different dating techniques were applied to the cave sediments and fossils, producing 157 radiometric ages.
Luminescence dating, which measures a light-sensitive signal found in the burial sediments that encased Gigantopithecus blacki fossils, was the primary technique, supported by uranium series and electron-spin resonance dating of the Gigantopithecus blacki teeth themselves.
“By direct-dating the fossil remains, we confirmed their age aligns with the luminescence sequence in the sediments where they were found, giving us a comprehensive and reliable chronology for the extinction of Gigantopithecus blacki,” said Southern Cross University geochronologist Dr. Renaud Joannes-Boyau.
The findings show Gigantopithecus blacki went extinct between 295,000 and 215,000 years ago, much earlier than previously assumed.
Before this time, Gigantopithecus blacki flourished in a rich and diverse forest.
By 700,000 to 600,000 years ago, the environment became more variable due to the increase in the strength of the seasons, causing a change in the structure of the forest communities.
Orangutans such Pongo weidenreichi adapted their size, behavior and habitat preferences as conditions changed.
In comparison, Gigantopithecus blacki relied on a less nutritious back up food source when its preferences were unavailable, decreasing the diversity of its food.
The primate became less mobile, had a reduced geographic range for foraging, and faced chronic stress and dwindling numbers.
“Gigantopithecus blacki was the ultimate specialist, compared to the more agile adapters like orangutans, and this ultimately led to its demise,” Professor Zhang said.
“With the threat of a sixth mass extinction event looming over us, there is an urgent need to understand why species go extinct,” Dr. Westaway said.
“Exploring the reasons for past unresolved extinctions gives us a good starting point to understand primate resilience and the fate of other large animals, in the past and future.”
The findings appear today in the journal Nature.
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Y. Zhang et al. The demise of the giant ape Gigantopithecus blacki. Nature, published online January 10, 2024; doi: 10.1038/s41586-023-06900-0
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