NAT GEO * This 10-foot ape was the largest primate ever. *

BYRILEY BLACK
PUBLISHED JANUARY 10, 2024









Never has there been a primate as big as Gigantopithecus blacki. Adults of this ancient ape stood about 10 feet tall and could weigh more than 500 pounds, wandering the thick forests of ancient China during the last Ice Age.
Why this impressive herbivore went extinct has stumped paleontologists since the ape was discovered nearly a century ago. But now, a new analysis suggests that the primate’s unique lifestyle left it vulnerable. As the forested home of Gigantopithecus rapidly changed, the ape couldn’t adapt to the expanding grasslands.
Published today in Nature, a new study combines geological dates, pollen records, and clues preserved inside fossil teeth to present a detailed timeline of when, and how, Gigantopithecus blacki went extinct. The results reveal the creature’s decline and ultimate demise in fine detail.






[size=14]Gigantopithecus blacki stood some 10 feet tall and weighed over 500 pounds, making it the largest known primate to ever live. 
ILLUSTRATION BY GARCIA/JOANNES-BOYAU, SOUTHERN CROSS UNIVERSITY



“My colleague Yingi Zhang had been working on G. blacki evidence for over ten years,” says Kira Westaway, lead author of the new study and a geochronologist at Macquarie University in Sydney, Australia. One of the largest unknowns was the timing of the giant primate’s disappearance.
Westaway worked to come up with more accurate dates for the sediments that Gigantopithecus fossils have been found in. If the researchers could work out the timing, then they could better investigate what the world of Gigantopithecus might have been like—and what could have eradicated the ape.
While experts had previously speculated that Gigantopithecus was driven to extinction as their preferred forest habitats became sparser, the known fossils of the ape lacked defined dates to test the idea. “Without a firm timeline, you end up looking for clues in the wrong places,” Westaway says. The survival of other apes that coexisted with Gigantopithecus only deepened the mystery. A relative of today’s orangutan, Pongo weidenreichi, lived through whatever changes had doomed Gigantopithecus.
Westaway and colleagues found that Gigantopithecus lived in China between 2.3 million and 215,000 years ago. “In the early caves around 2 million years ago, we find hundreds of G. blacki teeth,” Westaway says, “but in the younger caves around 300,000 years ago, at the edge of extinction, we only find a few.”
Studies of fossil pollen from the Gigantopithecus sites also allowed researchers to study how the animal’s habitat was changing during this interval. Around 700,000 years ago, dense forests of pines, birches, and chestnut relatives gave way to more open habitats with larger patches of grassland. Gigantopithecus declined and then disappeared as this environmental shift was taking hold.
The enormous ape would have felt the changes, as recorded in their teeth. Geochemical traces influenced by the plants the ape was eating are enclosed in its fossil teeth. Prior to 700,000 years ago, Gigantopithecus and Pongo weidenreichi lived in forests with overhead canopies where they ate leaves, fruits, and flowers, with delectable vegetation available much of the year round.
As the seasonal changes became more pronounced and the forest became more open, however, Gigantopithecus had a difficult time finding preferred foods. Meanwhile Pongo weidenreichi changed its diet to subsist on fibrous plants that were more readily available.
“The authors do a fantastic job showing that G. blacki was too specialized to adapt to the environmental changes that took place,” says Julien Luoys, a paleontologist with Griffith University in Australia, who was not involved in the new study. Southeast Asia was going through sweeping environmental changes during the time of the giant ape, he notes, as a tectonic plate in the area subsided, changing the local climate and habitats. “Imagine if most of the central parts of the U.S. went underwater, and you can begin to appreciate the huge changes that would ensue,” he notes.
What drove G. blacki to extinction, however, was not simply environmental change, but an inability to adapt quickly enough. “It was the response of G. blacki to these changes that sealed its fate,” Westaway says. The giant apes were so big that they had to move on the ground and were limited in how far they could venture, trying to make the most of out twigs, bark, and other tough foods that were still accessible. It wasn’t enough.
Around 215,000 years ago, the last Gigantopithecus perished as the apes could not keep pace with changing habitats. Yet knowing the ending of the ape’s story hardly closes the case on the giant primate. For reasons yet unknown, Westaway says, some of the last Gigantopithecus were among the largest.
Additionally, Luoys notes, fossils of Gigantopithecus have been described from Thailand, Vietnam, and possibly Java. Did these huge primates follow the same path to extinction, or did the story vary by location?
“What this paper achieves is a new level of detail that greatly adds to our understanding of extinction dynamics in Southeast Asia during this time,” Luoys says, opening new questions even as it explains the disappearance of Earth’s most stupendous ape.[/size]