We are all profoundly happy at the arrival of our new and endearing cub here at San Diego. Already we have witnessed new and different aspects of this birth and cub compared with our previous two, pointing out that we still have much to learn. Another opportunity raised by this birth is to highlight the larger picture of captive breeding and conservation of pandas worldwide.
Shortly after I witnessed the birth of the cub at 9:57 on Tuesday night I began to reflect on how much things have changed in the past ten years. In 1995 when I began my 10-year relationship with the Wolong Breeding Center in the mountains of Sichuan, China, the picture was a very different one. Each year the center produced at most a cub or two. Only two males would mate and only one reliably. Artificial insemination techniques were still being developed. Some mothers did not seem to know how to care for cubs. Globally, the captive population was shrinking, with deaths exceeding births. The famous giant panda scientist, George Schaller, had recently concluded in his book that the outlook for pandas both in the wild and captivity was bleak. Today, all that has changed.
Beginning in 1995 the San Diego Zoo began to send a team of CRES (Conservation and Research for Endangered Species) researchers and animal care personnel to Wolong. I studied behavior and other CRES scientists worked on problems of nutrition, endocrinology, and veterinary science. Their staff also came to San Diego to work with us here extensively in various specialties. There we developed working relationships and binding friendships. For several years I spent every breeding and birth season in Wolong, studying behavior and working with the staff to come up with improved husbandry and management. I can’t count the hours I’ve spent standing in the cold sleet and rain watching and learning about this endearing animal. In between the work hours I dined with my Chinese coworkers, played games, and resurrected a childhood love of basketball—it was the first time in my life I was considered tall enough to play center!
I remember some tragedies as well as successes. One cold September night in 1997 Ershiyi Hao gave birth to twins. From the get-go she was fearful. She approached and sniffed them, then ran away to a corner of the pen and paced around. “What are these crying, squirming things and what am I supposed to do with them?” she seemed to say. Both cubs had to be rescued and reared in the nursery. They made a heroic effort, even trying to return the cubs to the mother several times, but the end was certain. Without the mother the cubs would die. Ten days later they did. Even today there has only been a handful of cubs reared successfully without the mother, though twin swapping so that each cub is half mother-reared and half nursery-reared is almost always successful.
Spurred by this tragedy we made plans for the next time. The following September we got our chance. Ershiyi Hao gave birth to a single cub and again reacted with fear and bewilderment. This time when we pulled the cub for nursery-rearing we began to work on the mother immediately. To habituate her to the sounds and smells of her cub, we recorded and played back the cub’s cries to her and gave her a stuffed panda toy rolled in the cub’s urine. And almost to our surprise she began to pick up, hold and “comfort” this surrogate cub, often spending most of her time cradling it. Eventually, we slowly gave the cub back to the mother, first allowing it to nurse for a while and returning it to the nursery, but finally giving the cub over to her completely. The cub survived and thrived and Ershiyi Hao is now a grandmother.
The other success stories are numerous and compelling. Today at Wolong everything is different. The pandas live more enriched lives, often in semi-natural enclosures, and always exposed to lots of stimulating opportunities and “enrichment.” We have also found the recipe for success in getting pandas to do “what comes naturally.” Through careful management of social interactions—especially opportunities for olfactory communication through scent marking—we have figured how to get this species, solitary throughout most of the year, to come together for mating in the 2-3 day window of opportunity each spring. Today almost all pandas in Wolong mate naturally, and on the occasion that they don’t, artificial insemination is a highly successful backup. Today it is exceedingly rare to lose a cub and mothers routinely rear their own cubs without intervention, with the exception of twins, where they need help.
These days I don’t spend so much time in Wolong. Our very capable staff, who write most of these blog entries, took my place for awhile, but mostly the Wolong staff carries out their highly successful business of producing more pandas. Since 1996,when they had about 25 pandas, they’ve produced 50-some cubs. They’ve also established a “reintroduction pen,” where they raise cubs intended for release back into the wild. Today the captive population is secure and stands ready to reinforce the wild population where necessary. Better still, the Chinese government has made tremendous efforts to set aside more land for pandas, establishing more than 30 new reserves to secure the remaining 1,600 or so wild pandas.
With our newest addition to the panda family at the San Diego Zoo, I think this is an excellent time to reflect on these changes. The real message is that such a birth, while exciting and inspiring, is now commonplace. No longer enshrouded in mystery, the panda is now an animal that we understand, yet we still have more to learn. I am thankful for and indebted to our collaborators in Wolong. Without these experiences our panda team would not be so well prepared to breed pandas here in San Diego.
Ron Swaisgood is a scientist with the San Diego Zoo’s Office of Giant Panda Conservation.
View Bai Yun and her cub on Panda Cam.
File photo from 2001 of Hua Mei, a baby giant panda born at the San Diego Zoo on August 21, 1999.
A new giant panda cub has been born at the San Diego Zoo. Bai Yun, a 13-year-old giant panda, gave birth at 9:57 p.m. on Tuesday to a cub weighing four ounces (113.5 grams).

"Bai Yun immediately tended to her squawking infant," said Suzanne Hall, a panda research technician at the San Diego Zoo who observed the births of Bai Yun’s other cubs in 1999 and 2003. The cub is the second to be born in the United States this year. In Washington, Mei Xiang gave birth to a male panda cub at the National Zoo last month after artificial insemination.

According to Hall, early ultrasound images indicated Bai Yun was pregnant with twins. However, zoo personnel became suspicious that one fetus was no longer viable after veterinarians failed to detect a heartbeat in one cub last week. Bai Yun failed to give birth to a second cub Tuesday evening. "It is likely that the second fetus died in utero and was reabsorbed by her body," Hall said.

Panda behavioral researchers will be watching the pair 24 hours a day for three weeks to record and assess the mother-infant relationship. The new cub has not yet been named. The gender of the cub will be unknown until zoo staff can safely check.