National Geographic News

Mei Xiang, the National Zoo's giant panda, looks at her newborn cub on Friday.

Photograph courtesy Smithsonian National Zoo

Christine Dell'Amore

National Geographic

Published August 23, 2013

A giant panda at Smithsonian’s National Zoo in Washington gave birth to a cub Friday night, the latest chapter in a long saga of breeding attempts that has shown how very difficult it is for endangered giant pandas to reproduce.

The National Zoo's female panda, Mei Xiang, gave birth at 5:32 p.m. on Friday, then "picked up the cub and immediately began cradling and caring for it," the zoo said in a statement.

"Chief veterinarian Suzan Murray says that Mei Xiang & the cub appear to be doing well," the zoo said via Twitter.

 Baby panda.
The giant panda cub born 5:32 p.m. August 23 at the Smithsonian's National Zoo received an exam from animal care staff.

Photograph by Courtney Janney, Smithsonian National Zoo

But whether the cub will survive is far from certain. It is difficult for pandas to breed in the wild, let alone in captivity. A cub born to Mei Xiang last fall died six days later, a result of liver damage caused by underdeveloped lungs.

That pregnancy, and this latest one, came via artificial insemination, following failed attempts by scientists to get Mei Xiang to naturally breed with the National Zoo’s male giant panda, Tian Tian.

A team of vets had been glued 24-7 to the zoo’s Panda Cam since August 7, when Mei began showing signs of being pregnant.

Here’s a primer on what's so tricky about these animals' reproductive biology:

Female pandas ovulate just once a year, in the spring.

What's more, the female can only conceive for about two or three days around ovulation, which means she has to mate with a male during that period. Females can be fertile between the ages of about 4 to 20.

Generally solitary creatures, panda partners find each other in the wild via calls and scents, according to the National Zoo. Luckily for captive panda pairs, the male's nearby, but that doesn't mean mating is easy. Which is why ...

The pair has to be compatible.

Not only do they need to get along, the couple has to be "behaviorally competent"—meaning males need to know how to mount a female, San Diego Zoo panda veterinarian Meg Sutherland-Smith said by email. But sometimes pandas just aren't sure what to do. (Read about a Thai zoo that turned to "panda porn" to get its bears in the mood.)

The San Diego Zoo's panda pair, Bai Yun and Gao Gao, have mated naturally and are parents to five cubs, the latest born on July 29.

The National Zoo's male panda, Tian Tian, and Mei have had trouble mating naturally, but Mei has conceived before via artificial insemination. Tai Shan, born in 2005, was affectionately nicknamed Butterstick among D.C. fans due to a newborn panda's tiny size, and now lives in China. Mei was artificially inseminated again on March 30 of this year. (Watch a video of Mei's first baby, Tai Shan.)

Zoo Atlanta's pandas Lun Lun and Yang Yang have also failed to mate naturally, "probably because both lack an experienced partner," Rebecca Snyder, Zoo Atlanta's curator of mammals, said by email.

Fortunately, artificial insemination at Zoo Atlanta has produced five cubs, the latest a set of twins born in July, she said.

Chinese breeding centers have also been successful at using artificial insemination, noted Marc Brody, the Wolong Nature Reserve's senior advisor for conservation and sustainable development.

In China, panda bloodlines are also filed so that experts can pair pandas that are unrelated, which increases their chances of breeding and producing healthy offspring.

Pandas have pseudopregnancies.

A hormone spike in a female panda tells scientists that one of two things will happen in 40 to 55 days: She'll either give birth, or experience the end of a pseudopregnancy, also called a false pregnancy. (Read about the costs of breeding pandas in National Geographic magazine.)

According to the San Diego Zoo blog, "a pseudopregnancy occurs when a female exhibits the signs and symptoms of pregnancy when in fact she is not experiencing one."

The phenomenon—still not completely explained—has been observed in mice, dogs, and even people.

A panda fetus is extremely slow-growing, making it hard to detect pregnancy.

Giant pandas undergo what's called "delayed implantation," which means that once the egg is fertilized, everything gets puts on hold. The future fetus "virtually stops growing in the uterus and instead free-floats without growth until the time is right for it to implant in the uterine wall," the San Diego Zoo's blog explains.

That's usually within the last weeks of gestation, so zoo veterinarians often don't know if a panda is preggers until the little girl or guy pops out.

However, ultrasound technology has improved in recent years, Sutherland-Smith noted, and her team has been able to both detect pregnancies and predict roughly when Bai Yun will give birth.

Cubs are very needy and vulnerable at birth.

At three to five ounces, the hairless, blind newborn panda is 1/900th the size of its mother. According to the National Zoo, that makes it one of the smallest mammal newborns relative to its mother's size, trumped only by marsupials. Unable to move, the infant is reliant on the mother's warmth, milk, and protection to survive.

Mei's second cub, a female, was born in September 2012, but died a week later due to lung and liver damage, according to the zoo. Poorly developed lungs likely prevented the cub from getting enough oxygen.

Saving Wild Pandas

Ultimately, said Wolong's Brody, "captive breeding can only take us so far, and its greatest contribution isn't the birth of a single panda but the arousal of interest and support for panda conservation at large."

Possibly as few as 1,600 giant pandas still roam the mountainous forests of central China, according to the National Zoo, and more than 300 live in breeding centers around the world.

Some of the captive pandas in China have been reintroduced into their native habitat, "but the bigger question is not can we breed an animal in captivity, but can we give him a home in the wild—and that means restoring degraded and fragmented habitat," Brody said.

Zoo Atlanta's Snyder agreed.

"Captive breeding is just one tool to help conserve giant pandas," Snyder emphasized. "The wild population and its habitat must also be protected. I don't want pandas to only be found in zoos in the future."

Camille S.
Camille S.

Pandas are naturally carnivorous but too lazy to hunt. Cut out the bamboo and feed them meat. No soy products either.

robert rowley
robert rowley

this is brilliant how this species is being preserved nowadays,

when i was a child people told me that they would be extinct by now.

but i agree with Snyder that the natural habitat has to be preserved, one of the main destroyers of the habitats are the mining companies.

the world should take a look at Mexico which is trying to preserve its forests by extracting precious metals from seawater

Dale Clifton
Dale Clifton

@robert rowley 

Completely agree, we as humans have a responsibility to protect this world including the animals in it and their habitats, if it wasn't for deforestation breeding them in captivity would not be necessary.

Hopefully they can all be some day be returned to a safe natural habitat before they lose their survival instincts.

Environmental issues are not taken seriously at all in China and they're going to kill every living thing in their country.


Popular Stories

The Future of Food

  • Why Food Matters

    Why Food Matters

    How do we feed nine billion people by 2050, and how do we do so sustainably?

  • Download: Free iPad App

    Download: Free iPad App

    We've made our magazine's best stories about the future of food available in a free iPad app.

See more food news, photos, and videos »