National Geographic : 2016 Aug
66 national geographic • August 2016 breeding their iconic bear in captivity. The early years (until the late 1990s) saw a lot of failed attempts, both at breeding and at keeping cubs alive. And genetic diversity—which supports helpful adaptations and can protect a popula- tion from extinction—was a low priority. With assistance from abroad, the Chinese turned things around. David Wildt, of the Smithsonian’s Conservation Biology Institute, was part of the international team that first worked with Chinese scientists on panda biol- ogy and husbandry. “Pretty soon they had piles of baby pandas,” he says. “In a sense we trained ourselves right out of a job.” Now “pandas are one of the most genetically diverse animals in captivity,” says Wildt’s colleague, geneticist Jon- athan Ballou, who developed the algorithm that the Chinese now apply to breeding decisions. Much of the action happens at Bifengxia Panda Base, or BFX, where I had my close-up with cubs. Visitors here can see adult bears in outdoor yards—hunched over broad bellies, chomping messily on long bamboo stalks from enormous piles delivered several times a day. Up a hill from these exhibits lies the staff-only building where bears in the breeding program reside. Enclosures are concrete with iron-barred doors; each opens to an outdoor pen. Typically there is a female panda in each, eating or sleep- ing, sometimes with a cub in her arms. “Even after many years, whenever a panda is pregnant or gives birth here, everyone is so joyful and excited,” Zhang Xin, a rather bearlike veteran keeper, told me. “ We look every day at the adults, the babies, how much they are eating, what their poo looks like, if their spirit is good. We just want them to be healthy.” In this setting, little about panda production is natural. Dropping a male in with a female can even lead to aggression instead of mating. To set the mood, breeders in China have tried “panda porn”—videos of pandas mating—mostly for the record, exactly when they diverged from other bears isn’t clear. A jaw from Spain puts an early panda relative at 11.6 million years old, while DNA evidence suggests 18 million. And bones from a cave in China indicate giant pandas as we know them are at least two million years old. The exact timing and reason for pandas going vegetarian is debated, but those eons of adapta- tions leave modern pandas with some unique tools, including flat molars for crushing and a thumblike appendage, an extension of the wrist bone, helpful for handling bamboo. Interestingly, they lack any special gut microbes to break down the bamboo that has become 99 percent of their food—one reason they are relatively low-energy animals. To derive enough nutrients, pandas eat 20 to 40 pounds of plant material a day. To satisfy their love for particular flora that grows best beneath big, old trees with hidey- holes for stashing cubs, pandas can’t live just anywhere. But that specialization is now work- ing against them. The species used to range across southern and eastern China and north- ern Myanmar and Vietnam. Now they’re found in patchy mountain habitat only in China, in perhaps one percent of their historic range. How many wild pandas are out there? Researchers have been trying to count them since the 1970s, when it is thought there were roughly 2,500 animals. That dropped dramati- cally in the 1980s, in part because of a periodic natural die-off of bamboo. (Normally pandas can survive such natural ecological events by shifting to more fruitful habitat, but if there’s nowhere to move, they’ll starve.) The Chinese government’s most recent sur- vey, from 2014, reported 1,864 in the wild, 17 percent more than in 2003. But Marc Brody, a National Geographic grantee who founded the conservation nonprofit Panda Mountain, warns that it’s tough to trust any specific figures. “ We may just be getting better at counting pandas,” he says. Also, it’s difficult to compare numbers across the decades because ranges and survey methods have varied; today they include DNA analysis of panda poo. In the meantime, the Chinese are furiously Tune in to Panda Babies: Mission Critical on August 28 at 8 p.m. to follow their develop- ment at three breeding centers.