Advertisement
Advertisement
Science
Get more with myNEWS
A personalised news feed of stories that matter to you
Learn more
The giant panda’s false thumb is “not the most elegant or dexterous”, but it has played an essential role in the bears’ survival, according to scientists. Photo: Sharon Fisher

How long have pandas been eating bamboo? At least 6 million years, study suggests

  • Fossils unearthed in southwestern China show panda ancestors had ‘false thumb’ for grabbing food
  • Researchers say the bears’ sixth digit never fully developed because it would have impeded walking ability
Science
Giant pandas might have started their bamboo diet 6 million years ago, according to a new study examining a thumblike digit that panda ancestors used to grip their food.
An international team of scientists based their analysis on a fossil of an Ailurarctos – an extinct ancestor of the modern panda – unearthed from Shuitangba in the southwestern Chinese province of Yunnan. The site dates back to the late Miocene period, or about 6 to 7 million years ago.
The fossil is the earliest example of an enlarged radial sesamoid – a bone that functions as an opposable thumb – in the panda’s lineage, according to the article published in the peer-reviewed journal Scientific Reports on Thursday.

Winter Olympics: outrage after panda mascot Bing Dwen Dwen speaks like a man

Scientists have known about the animal’s “false thumb”, which allows pandas to survive on an all-bamboo diet, for more than a century. But previous research only found evidence of the sixth digit dating from 100,000 to 150,000 years ago.

The researchers found that the bone has stayed the same size since the late Miocene period and never evolved into a fully developed thumb.

The scientists proposed that the lack of elongation was the result of a compromise between the need to grab bamboo and the false thumb’s weight-bearing function.

When pandas walk, the bottoms of their paws touch the ground. If the sixth digit had grown longer, it would have compromised the bone’s dual functions – grasping and weight-bearing – and interfered with walking long distances.

00:54

Panda urinates on tree while doing an impressive handstand

Panda urinates on tree while doing an impressive handstand

“Pandas never evolved sufficiently long false thumbs to seize large bundles of bamboo, a task that, while desirable, is not critical for survival,” the researchers said, pointing to the abundance of bamboo in their habitat.

The team said it was “likely that a tight grip is more critical to the panda’s feeding ability than the volume of their grasp”, because pandas needed a strong grip to counter their powerful jaws as they eat the thick, woody grass.

“While the giant panda’s false thumb is not the most elegant or dexterous, the persistence of this distinctive morphology for the last 6 million years suggests that it has fulfilled an essential function for survival of the lineage,” they said.

Researchers say panda thumbs did not grow long enough to seize large bundles of bamboo because it would have interfered with the animals’ ability to walk long distances. Photo: Handout

The team was led by Xiaoming Wang of the Natural History Museum of Los Angeles County and includes researchers from Arizona State University, Pennsylvania State University, Harvard University, as well as the Institute of Vertebrate Palaeontology and Paleoanthropology and Kunming Institute of Zoology – both under the Chinese Academy of Sciences.

Around 1,900 giant pandas live in the wild in remote mountain forests of Sichuan, Shaanxi and Gansu provinces in south-central China. They are considered “vulnerable” to extinction.

Giant panda cub Xiao Qi Ji rocks it in new Instagram video

Giant pandas spend around 15 hours a day eating up to 45kg (99lbs) of bamboo. They traded the high-protein, omnivorous diet of their ursid ancestors for bamboo – a high-fibre food with little nutritional value but year-round availability in South China and Southeast Asia, according to the researchers.

“With 99 per cent of their food being bamboo and without major competitors for this abundant food resource, nor the need to avoid predators, pandas can thus reduce daily foraging range to within tens of metres of their resting dens, permitting a highly efficient foraging strategy of spending large portions of daily activities feeding and resting within small areas,” they said.

Post