But their ancestors, like most bears, ate a wider diet that included meat, The exclusive diet of the modern panda was thought to have developed relatively recently. However, a new study He found that the panda’s passion for bamboo may have originated at least 6 million years ago – possibly due to the year-round availability of the plant.
To survive only on low-nutrient bamboo, modern pandas (Ailuropoda melanoleuca) have evolved a curious sixth toe, a type of thumb that allows them to easily grasp bamboo stems and strip leaves.
“Tightly gripping bamboo stalks in order to crush them into bite sizes is perhaps the most important adaptation to consuming a massive amount of bamboo,” said study author Xiaoming Wang, curator of vertebrate paleontology at the Los Angeles County Museum of Natural History. statement.
Wang and his team identified early evidence of an extra toe for a panda – and thus a whole bamboo diet – in the form of a fossilized figure dating back 6 to 7 million years. The fossil, discovered in Yunnan Province, southwest China, belongs to the ancestor of the panda known as Ailurarctos.
The new research was published Thursday in the journal Scientific Reports.
The study indicated that while the sixth digit of the giant panda is not as elegant or dexterous as the human thumb, the persistence of this “distinctive morphology” over millions of years suggests that it plays an essential function for survival.
an evolutionary compromise
But what was particularly puzzling to the scientists involved in the study was that this fossilized skeleton was even longer than those of modern giant pandas, which have a shorter, hanging sixth toe.
Wang and his colleagues believe that the sixth number is the shortest in modern pandas It is an evolutionary compromise between the need to manipulate the bamboo and the need to walk and carry their heavy bodies.
“Five to six million years should be enough time for pandas to develop a longer pseudo-thumb, but it appears that the evolutionary pressure of needing to travel and bear its weight kept the ‘thumb’ short – strong enough to be useful without being large,” said Dennis Su, co-author of the study. “Enough to get in the way,” R., an associate professor in the School of Human Evolution and Social Change and a research scientist at the Human Origins Institute at Arizona State University, said in a statement.