BEJING: Extinct and ancient species of pandas were not exclusive bamboo eaters, and probably had a more varied and complex diet, according to one study.
The giant pandas that we know today live only in the understory of particular mountains in southwest China, where they subsist only of bamboo.
In support of their hard and fibrous bamboo diet, pandas have distinctive teeth, skulls and muscular features along with a special pseudo-thumb to grasp and hold bamboo stems, leaves and buds.
"It has been widely accepted that giant pandas have exclusively fed on bamboo in the last two million years," said Fuwen Wei of the Chinese Academy of Sciences.
However, the study, published in the journal Current Biology, shows otherwise.
Researchers first looked at the bone collagen of modern pandas (70s and 2000s) and other mammals from the same mountains.
The stable isotopic composition of the carbon and nitrogen of modern panda and other modern mammalian bone samples indicates three obvious groups: carnivores, herbivores, and giant pandas.
Isotopes are different forms of the same element that contain equal numbers of protons, but different numbers of neutrons.
Giant pandas were clearly unique because of their habit of eating bamboo, the researchers said.
The team measured isotopes of bone collagen from 12 ancient pandas collected at seven archaeological sites in south and southwestern China and compared them to the patterns observed in modern giant pandas.
Comparison of the data showed that the ancient and modern pandas are isotopically distinct from each other, suggesting differences in their eating habits.
There was also more variation among ancient pandas species, suggesting that the niche they occupied was about three times larger than that of modern pandas.
Ancient pandas probably had a varied diet, similar to other mammalian species that lived next to them.
They "probably were not exclusive bamboo feeders," the researchers said.
The study suggests that eating habits of pandas evolved in two phases.
First, pandas have gone from meat eaters or omnivores to become dedicated plant eaters.
Only later did they specialize in bamboo, the researchers said.