It was a battle fought in the mountains of southwestern China, where patchy forests sustain the last shreds of the wild giant panda population.
All at once, intruders began marching in and helping themselves to the pandas’ food. The incursion happened far from most human eyes, and the pandas that witnessed it likely didn’t know what to think. It’s not often that one sees a horse in a bamboo forest.
In these woods, the Wolong National Nature Reserve is an important refuge for pandas.
About a tenth of the entire wild panda population lives there—although that amounts to only 150 or so animals. They share the space with around 5,000 humans, most of whom are farmers who graze their livestock in designated areas.
A new trend emerged among these farmers in the 2000s as they began to do more business with an adjacent township where horses are reared. Though the Wolong farmers had previously raised cattle, pigs, goats, and yaks, they now began buying horses too.
“We first realized the problem while we were hiking in panda habitat and conducting habitat sampling for our research in 2009,” says Vanessa Hull, a graduate student at Michigan State University.
Large areas of forest were “mowed down by horses,” she says. “It was honestly a shock to me.”
When existing grazing areas couldn’t provide enough grass for both their cattle and their new horses, the farmers had sent the horses to wander in the forest.
There the grazers were happily munching on bamboo—essentially the only thing a wild panda eats. Pandas don’t normally have any competition for their food, and Hull worried that the intrusion from horses was driving the vulnerable pandas away.
Hull and her colleagues began monitoring four horse herds in Wolong.
They put a GPS collar on one member of each of three herds, to track where the herds traveled.
They also put collars on three pandas. It was a tiny number of animals, but they felt lucky to even study that many, Hull says, because government protection of the species is so strict. “It is very difficult to get permission to do telemetry research on giant pandas.”