Big pandas are notoriously fussy eaters. They solely munch on bamboo and every day spend 15 hours consuming as much as 99 kilos (45 kilograms) of the stuff.
However their ancestors, like most bears, ate a a lot wider food plan that included meat, and it was thought that trendy pandas’ unique food plan advanced comparatively lately. Nevertheless, a brand new examine finds that pandas’ specific ardour for bamboo might have originated a minimum of 6 million years in the past – presumably as a result of plant’s large, year-round availability.
To outlive solely on low-nutrient bamboo, trendy pandas (Ailuropoda melanoleuca) have developed a peculiar sixth finger, a thumb of kinds that permits them to simply grasp bamboo stalks and strip the leaves.
“Tightly holding bamboo stems as a way to crush them into chew sizes is maybe essentially the most essential adaptation to consuming a prodigious amount of bamboo,” stated examine writer Xiaoming Wang, curator of vertebrate paleontology on the Pure Historical past Museum of Los Angeles County, in a press release.
A scant panda fossil report meant that how the bears advanced this perplexing function that has lengthy baffled biologists wasn’t actually understood. Earlier analysis had discovered proof of this thumblike construction from about 100,000 to 150,000 years in the past.
Wang and his crew recognized a lot earlier proof of pandas having an additional finger – and thus an all-bamboo food plan – within the type of a fossilized digit relationship again 6 to 7 million years. The fossil, unearthed in Yunnan Province in southwest China, belonged to a panda ancestor often known as Ailurarctos.
The brand new analysis printed Thursday within the journal Scientific Reviews.
Whereas the large panda’s sixth digit shouldn’t be as elegant or dexterous as human thumbs, the persistence of this “distinctive morphology” over hundreds of thousands of years recommended that it performs a vital perform for survival, the examine famous.
However what was significantly puzzling to the scientists concerned within the examine was that this fossilized construction was longer than these of contemporary big pandas, which have a shorter, hooked sixth finger.
Wang and his colleagues assume trendy pandas’ shorter sixth digit is an evolutionary compromise between the necessity to manipulate bamboo and the necessity to stroll and carry their hefty our bodies.
“5 to 6 million years must be sufficient time for the panda to develop longer false thumbs, however evidently the evolutionary strain of needing to journey and bear its weight saved the ‘thumb’ quick – robust sufficient to be helpful with out being large enough to get in the best way,” stated examine coauthor Denise Su, an affiliate professor on the College of Human Evolution and Social Change and analysis scientist on the Institute of Human Origins at Arizona State College, in a press release.