In the karst landforms of southern China, the great ape (i.e., black giant ape, gigantopithecus, gBlacki) used to walk through here. These behemoths, which are three meters tall and weigh about 250 kilograms, are considered distant relatives of humans. Although they disappeared before humans settled the area, the reason for their extinction remains largely a mystery. The only evidence that they ever existed is about 2000 fossilized teeth and four jawbones.
Artistic impression of a herd of black bears in a forest in southern China. Source**: Garcia Joannes-Boyau (Southern Cross University).
New evidence from this region, published in the journal Nature by a team of researchers from China, Australia and the United States, leaves no doubt that the largest primate on Earth was found 29 years ago50,000 to 21They became extinct between 50,000 years because they were unable to adapt to food preferences and behaviors, and were vulnerable to a changing climate, which determined their fate.
Paleontologist and co-author Professor Yingqi Zhang of the Institute of Vertebrate Paleontology and Paleoanthropology said:"The story of the black giant ape is a mystery in paleontology – how could such a powerful creature become extinct when other primates were adapting and surviving? Professor Yingqi Zhang, a paleontologist and co-first author at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences, said:"The reason for its disappearance hangs in the balance, which has become the holy grail of this discipline. The IVPP has been excavating evidence of black great apes in this area for more than 10 years, but we have not been able to find the cause of their extinction due to the lack of reliable dating and consistent environmental analysis"。
Conclusive evidence to uncover the story of the extinction of the great apes comes from a large-scale project that collects evidence from 22 cave sites spread across a vast area of Guangxi province in southern China. The basis of this research is dating.
Co-first author Associate Professor Kira Westaway, a geochronologist at Macquarie University, said:"Coming up with a clear cause of a species' extinction is a major feat, but determining the exact time for a species to disappear from the fossil record gives us a target time frame for environmental reconstruction and behavioral assessment. "
Excavations in hard, cemented cave sediments with abundant fossils and evidence of black giant apes. Source**: Kira Westaway (Macquarie University).
Six Australian universities have contributed to the project. Macquarie University, Southern Cross University, University of Wollongong, and the University of Queensland used a variety of techniques to date the samples. Southern Cross University has also mapped the teeth of black giant apes to extract information about ape behavior. The Australian National University (ANU) and Flinders University have studied pollen and fossil-containing sediments in caves, respectively, to reconstruct the environment in which black apes flourished and disappeared.
Six different dating techniques were used on cave sediments and fossils, yielding 157 radioactive ages. These techniques were combined with eight pieces of environmental and behavioral evidence and applied to 11 caves containing evidence of black-bellied clams, and 11 caves of similar age where no evidence of black giant apes was found.
The location of many caves, including two caves infested by black giant apes. Source**: Yingqi Zhang (Chinese Academy of Sciences IVPP).
Luminescence dating is the primary dating technique, which measures the light-sensitive signal in the buried sediment encapsulated with the fossils of the black great ape, supplemented by uranium series (US) and electron spin resonance (US-ESR) dating of the teeth themselves.
Associate Professor Renaud Joannes-Boyau, geochronologist at Southern Cross University, said:"Through direct dating of the fossil remains, we confirmed that their age is consistent with the luminescent sequence in the sediments in which they were found, thus providing us with a comprehensive and reliable chronology of the extinction of the black great apes. "
Through detailed pollen analysis, fauna reconstruction, stable isotope analysis of teeth, and microscopic detailed analysis of cave sediments, the team determined the environmental conditions that preceded the extinction of the great apes. The team then used trace elements from ape teeth and tooth microwear texture analysis (DMTA) to simulate the behavior of populations during periods of prosperity versus periods of extinction.
The black great ape habitat cave is 150 meters above the valley floor and needs to be climbed every day to be excavated. Source**: Kira Westaway (Macquarie University).
Assoc. Prof. Joannes-Boyau said"Teeth provide a shocking insight into species behavior, showing stress, food** diversity, and repetitive behavior. "
The results of the study suggest that the black giant ape became extinct at 29 years ago50,000 to 2150,000 years, much earlier than previously speculated. Before that, they thrived in rich and diverse forests. Between 700,000 and 600,000 years ago, the environment became more variable due to the intensification of seasonal changes, leading to changes in the structure of forest communities.
Orangutans - close relatives of black great apes adjust their size, behavior, and habitat preferences as conditions change. In contrast, when the preferences of the black great ape are not met, it relies on backup foods with lower nutritional value**, reducing the diversity of its food.
Professor Zhang said"Compared to more adaptable animals such as orangutans, chimpanzees appear difficult to adapt, which eventually led to its demise. "
With the threat of a sixth mass extinction looming, there is an urgent need to understand the causes of species extinction. Exploring the causes of unresolved extinction issues in the past provides a good starting point for understanding the resilience of primates and the fate of other large animals in the past and future.
Compilation**: scitechdaily