The discovery of fossils of a panda ancestor in China has allowed researchers to unravel the mystery of the “sixth toe” that enables it to grasp the bamboo stalks that make up the bulk of the mammal’s diet.

Fossils, about six million years old, were discovered in southwestern China’s Yunnan province. Between them is a particularly large wrist bone called the radial sesamoid.

In the latest issue of the journal, the researchers noted the earliest evidence of the existence of a “sixth finger” in the giant panda, which allows it to grasp and break thick bamboo stems. Scientific Reports.

These fossils belong to the ancestor of the now extinct panda Ailurarctos, who lived in China six to eight million years ago.

“The giant panda … it is a rare case that a large carnivore … becomes an herbivore,” said Wang Xiaoming, curator of vertebrate paleontology at the Los Angeles County Museum of Natural History.

“The ‘false thumb’ (…) of Ailurarchtos shows for the first time the chronology and possible stages of the evolution of bamboo feeding in pandas,” he added.

Although the existence of the “false thumb” has been known to researchers for nearly a century, fossil findings from this bone shed light on many long-unanswered questions, such as how and when this extra-terrestrial finger evolved. . There are no other bears.

Millions of years ago, pandas traded their ancestral protein-rich, omnivorous diets for nutrient-poor bamboo available year-round in Southern China.

Pandas eat up to 15 hours a day, and an adult panda can consume up to 45 pounds of bamboo per day. Although their diet is mostly vegetarian, giant pandas are also known to occasionally hunt small animals.