Pandas search high and low to get their fill of different bamboos

Chinese and Australian scientists find pandas migrate long distances to maintain a balanced diet which helps them breed

Pandas may have been unfairly maligned over their seemingly futile devotion to bamboo. Research has found that the animals switch between species of the plant to reproduce.

A six-year study has found that pandas migrate relatively long distances to eat different parts of two bamboo species – arrow bamboo and wood bamboo – to maintain a balanced diet and to get the nutrients they need to breed.

Researchers, led by the Chinese Academy of Sciences and Sydney University, attached GPS collars to seven pandas in Foping reserve in Shaanxi, central China.

The study was able to confirm the theory that pandas move up from the valleys of the Qinling mountains to higher ground in spring, and back to lower ground in autumn.

When on higher ground, about 2,500m above sea level, the pandas can obtain vital protein from bamboo shoots. But calcium-rich leaves aren't in edible form at this height so the black and white mammals have to descend to lower ground to eat these leaves.

Pandas need calcium to help them reproduce – albeit that the animals are as notorious for their lack of breeding as they are for their fussy diets.

Researchers said the work shows that pandas' culinary habits are a little more sophisticated than they have been given credit for, with bamboo often considered a poor nutritional choice.

"The concept of bamboo being a bad food for pandas is nonsense," professor David Raubenheimer of Sydney University, and study co-author, told Guardian Australia.

"Pandas have adapted to bamboo; it's their food. When you look at it more closely you understand there are patterns of movement needed for diet and reproduction.

"Yes, for many herbivores eating bamboo would be a challenge because the nutrients are very diluted. But pandas cope with this by eating large amounts of it. They live in a sea of the stuff and they can eat for 16 or 17 hours a day. They've got all the time in the world to sit there and eat it."

Raubenheimer said the research had important conservation implications for the giant panda, which has an estimated wild population of just 1,600.

"Because pandas have to trek 20 to 30 kilometres to different places for their food, we can't think of these two habitats as optional extras to maintain," he said. "Pandas need both habitats conserved. It may look like they have enough bamboo in one location but they need the calcium, nitrogen and protein from different areas.

"Pandas used to be far more widespread but the encroachment of villages has pushed them up the mountains. We really need to make sure these two habitats are conserved."

guardian.co.uk