The great apes of Bu used to roam the karst regions of southern China in large groups. It can reach a height of 3 meters and weigh up to 300 kilograms, making it the largest primate ever built on Earth. This distant relative became extinct before we humans arrived in the area. To date, only nearly 2,000 teeth and 4 incomplete jaws have been able to prove that they ever existed. As for the reasons for its extinction, we know even less.
Courtesy of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences.
Recently, the research team of Zhang Yingqi from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences collaborated with several scientific research teams from Australia, the United States and other places to solve the mystery of the extinction of the giant ape, and the research results were published in the top international academic journal Nature on January 11, 2024, Beijing time. The study showed that at 295—21.50,000 years ago, it was the obsession with feeding behavior and food preferences that made the great ape vulnerable to environmental changes and locked in its extinction.
The extinction of the great apes seems somewhat inconceivable in paleoanthropology. Other primates living in the same area at the time were able to adapt and thrive, but how did this impressively powerful ape become extinct? This issue has always been a respectable problem in the discipline. Although the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences has carried out a systematic investigation in the area for more than 10 years and collected more fossil evidence of the Giant Aperture, the reasons for the extinction of the Great Ape are still bothering us due to the lack of targeted systematic dating and paleoenvironmental analysis with clear age intervals.
Reconstruction of the great ape of the step.
The multiple conclusive evidence that truly unravels the mystery of the extinction of the great apes comes from an intricately multidisciplinary and comprehensive study. Since 2015, the research team has investigated hundreds of cave fossil sites in Guangxi, China, and selected 22 of them for sample collection. It includes not only 11 sites where the fossils of the great apes were produced, but also 11 sites that did not produce fossils of the great apes of the later era. On this basis, the research team applied six independent dating techniques to the fossil-bearing deposits and the fossils themselves, and obtained a total of 157 radiometric dating results. These chronological data are combined with the analysis results of eight aspects, including pollen, mammalian fauna, and stable isotopes of teeth, trace elements, and microabrasions, to show us a comprehensive picture of the causes and consequences of the extinction of the great apes. Six Australian universities in the research team participated in the processing, testing and analysis of the samples.
In this study's vast data set, the results of dating are the starting point and cornerstone. This is because it is inherently challenging to determine the exact cause of a species' extinction, but it is first necessary to determine the exact time when the species disappeared from the fossil record in order to have a targeted time frame within which paleoenvironmental analysis and feeding behavior can be reconstructed. On the contrary, if there is no reliable dating data to support it, it can only be misled by the wrong clues in the wrong time range.
Luminescence dating, which measures the light-sensitive signal in the sediment of buried A. stephen fossils, is the main dating technique used in this study, supplemented by the enamel method (US) and electron spin resonance method (US-ESR) for direct determination of the fossil teeth of A. stephen. Direct dating of fossils ensures that their age corroborates with the luminescence dating of the sediments in which they were buried. In this way, a comprehensive and reliable window and timeline of the extinction of the great apes can be obtained.
Restoration of the life scene of the giant ape.
The research team also reconstructed the environmental conditions that led to the eventual extinction of the great apes through detailed analysis of pollen, mammals, stable isotopes of teeth, and microscopic analysis of cave deposits. Then, through the analysis of tooth trace elements and micro-grinding mark texture (DMTA), a comparative model of feeding behavior between the flourishing and extinction periods of Steptus was established. Although it is somewhat unbelievable, tooth tissue does contain a wealth of information related to the feeding behavior of species, which can be used to deeply understand whether they are under survival pressure, as well as the diversity of their food resources, feeding behavior regularity and range of activities.
In short, the results of this comprehensive study suggest that the extinction of the Giant Ape was 295~21.50,000 years ago, much earlier than people knew before. Before the extinction of the great apes, they flourished in forests with abundant and diverse food resources.
About 700,000 to 600,000 years ago, the environment began to become more diverse due to seasonal enhancements, resulting in changes in the structure of forest communities.
The pongo, a close relative of the great ape, has become smaller and more flexible in size while living conditions have changed, as well as changes in feeding behavior and habitat preferences, and their fossils have shown flexible and nutritionally balanced food choices, as well as less stress to survive. On the contrary, the great apes of Bu still rely on nutritious alternative foods despite the scarcity of their preferred food resources, which greatly reduces the diversity of their food. Despite this, they are becoming larger and bulkier, and the geographical range of their feeding activities has been greatly reduced. As a result, the population has been under pressure for a long time to survive, and it has been shrinking continuously, eventually going extinct.