The discovery of fossils of a panda ancestor in China has allowed researchers to solve the mystery surrounding the mammal’s “sixth inch.” This allows him to grab the bamboo stalks that make up most of his food.
The fossils, which are about six million years old, were discovered in Yunnan province in southwest China. Among them is a particularly large carpal bone, called the radial sesamoid.
This is the oldest known evidence of a “sixth finger” in a giant panda, which allows it to grasp and break thick bamboo stems, the researchers point out in the latest edition of the review..
The fossil belongs to a now-extinct panda ancestor known as Ailurarchtos that lived six to eight million years ago in China.
The chronology of the “false thumb” is established
“The giant panda is a rare case of a large carnivore,” said Wang Xiaoming, curator of vertebrate paleontology at the Los Angeles County Museum of Natural History.
“The Ailurarctos ‘false thumb’ shows for the first time (…) the possible chronology and evolutionary stages of bamboo feeding in pandas,” he added.
Although the existence of the “false thumb” was known to researchers over a century ago, the fossil evidence of this bone sheds light on many long-unanswered questions, including how and when this extra finger developed. No other bears have spawned.
Up to 45 kg of bamboo is available per day
Millions of years ago, pandas switched their ancestors’ omnivorous, protein-rich diet to nutrient-poor, year-round bamboo in southern China.
They eat up to 15 hours a day and an adult panda can eat 45 kg of bamboo every day. Although their diet is primarily vegetarian, giant pandas are known to occasionally hunt small animals.
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