The largest ever primate, once based in southern China, went extinct before humans arrived in the region. Recently researchers from China, Australia and the U.S. uncovered new evidence demonstrating how these very distant human ancestors went extinct, and the result is published in the top academic journal Nature. Our reporter Liu Jiaxin has more.

The larger the better? That's not usually the case when it comes to living creatures, such as these three-meter-tall apes weighing in at 250 kilograms. They are Gigantopithecus blacki, the largest ever primate to walk the earth. For centuries, their cause of extinction has been a mystery, until a group of researchers uncovered it from the caves of southern China's Guangxi Zhuang Autonomous Region, where G.blacki once roamed. Some of the only remaining signs of existence of these giants were showcased at a press briefing in Beijing.

LIU JIAXIN Beijing: "These are the teeth and jaws of the giants that scientists have found, and based on the size of their teeth alone, they were far larger than present-day humans. Fossil teeth are very important relics, as they can provide staggering insights into aspects of the species including stress levels, food sources, and repeated behaviors."

Prof. ZHANG YINGQI, Palaeontologist and co-lead author, IVPP, Chinese Academy of Sciences: "As our teeth grow, they form banding in which trace elements are deposited. If the bandings are clear, it means that the ape's food was sufficient and very diverse at that time, especially the two trace elements strontium and barium. If the lead bandings are clear, it means the giant apes have adequate water sources and drink regularly."

Through dating and tracing techniques, the findings show G.blacki went extinct between 295,000 and 215,000 years ago. Before this time, the giants flourished in a rich and diverse forest. But when climates changed and woody vegetation decreased, instead of adapting their size, behavior and habitat preferences like other agile apes, they relied on a less nutritious back up food source and faced chronic stress. This inflexibility and specificity, as researchers say, led them to their demise.

DENG TAO Director of Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences: "Whether it's out of worry or based on scientific evidence, a sixth mass extinction are looming over us. The ecological crisis faced by primates, including these great apes, has important implications for mankind."

The end of G.blacki's fate once again confirms an irrefutable conclusion of "survival of the fittest." Starting from 2015, the study was accomplished by a joint effort of Chinese, Australian and U.S. researchers.

Liu Jiaxin, CGTN, Beijing. (CGTN)