This year, Zoo Vienna welcomed Fu Bao, or "Happy Leopard." Madrid celebrated the birth of Xing Bao, or "Star Treasure." And in Washington, D.C., the arrival of Bao Bao, or "Precious Treasure," had panda fans glued to panda cams.
In all, 2013 saw the birth of 49 panda cubs around the world, and 42 of them have survived. That's a record and an indication that captive breeding programs are working. There are now a total of 376 pandas living in captivity, most of them in China.
The steady gains in the panda population have brought not only more adorable photos, but also better science for researchers to draw on.
In July, when Zoo Atlanta's female panda Lun Lun surprised keepers with twins, the staff quickly implemented a swapping technique developed by researchers in China to keep both cubs alive.
The Chinese had observed that panda mothers would not care for two cubs at once. Given how tiny and vulnerable cubs are at birth, one would almost certainly die without care.
So in Atlanta, while Cub A was with mother Lun Lun, Cub B was kept warm in an incubator. For the first few weeks, the cubs were swapped every two hours, and later, every three to four hours.
Rebecca Snyder, Zoo Atlanta's curator of mammals, says these kinds of discoveries have really made a difference.
"I think the research has been a key reason that the captive population is doing so well now. Applying that to the wild population is not so easy," she says.
Snyder hopes visitors to the zoo will be inspired to do something for panda conservation.
"I hope that they see our cubs and then think about cubs that were born last fall in the wild, and want to do something to make sure those cubs also have a bright future," Snyder says.
Growing Numbers And Genetic Diversity
The Chinese government's last survey of pandas puts the wild population at roughly 1,600 animals. A new survey is expected to be released next year.
Jonathan Ballou, population manager at the Smithsonian Conservation Biology Institute and the National Zoo, worries that the remaining panda habitat is fragmented, so pandas cannot roam from one forest to another.
"It's not 1,600 animals in some big huge forest," he explains. "It's 1,600 animals that are spread among a dozen or so forests, and some of them have very few animals. So there is going to be inbreeding and there are going to be catastrophes like landslides, which destroy the habitat."
Ballou's focus now is on preserving as much genetic diversity as possible in the captive population, with the aim of breeding pandas that, as a group, are hardier and less vulnerable to disease. The ultimate goal is to return that genetic diversity to the wild.
To determine each panda's genetic value, Ballou came up with something called a "mean kinship formula." Pandas with fewer relatives have a higher value than those with a lot of relatives. Each year, Ballou is part of a team that travels to China to make recommendations for matches based on these numbers.
The Intricacies Of Panda Matchmaking
There are some animals Ballou won't recommend for breeding, such as Pan Pan, a 28-year old male who has fathered 32 offspring and has a total of 119 descendants, including Bao Bao, the new cub in Washington, D.C. Ballou says Pan Pan's genes are overrepresented in the gene pool.
Ballou is most interested in cubs of "founders," wild-born pandas that are rescued, usually after wandering into villages hungry or sick.
"If I know the mom and dad are wild-caught animals and haven't bred before, that makes me the most excited, getting these genes into the population," he says.
In China, researchers have begun reintroducing captive pandas into the wild. Ballou believes that sometime soon they'll be talking about matching pairs of pandas to produce cubs specifically for this purpose.
Currently, the goal is to reach a total of 500 pandas in captivity, which Ballou thinks they'll hit within a few years. That's the number needed to preserve 90 percent of captive pandas' genetic diversity for 200 years.
"What happens now is going to be important in the long term for these guys," he says.
ROBERT SIEGEL, HOST:
From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel. And now, another number of the year. In these waning days of 2013, we've been looking at numbers that tell us something about what's happened around the world and today our number is 42. And we don't mean the answer to the question, life, the universe and everything. Forty-two is the number of giant panda cubs that were born in captivity this year and survived. NPR's Andrea Hsu explains what the number tells us and what it doesn't tell us about pandas.
ANDREA HSU, BYLINE: Madrid welcomed Xing Bao, Vienna got Fu Bao and in Washington, D.C., hello, Bao Bao.
(SOUNDBITE OF BAO BAO CRYING)
HSU: Here she is at a checkup just shy of eight weeks. Forty-two surviving cubs in one year is a record and brings the total number of pandas in captivity to 376, most of them in China, of course. The steady gains in the panda population mean not only more unbearably cute photos to coo over, but also better science for researchers to tap.
So, for example, this summer, Atlanta's Lun Lun made this news.
UNIDENTIFIED WOMAN: This mama panda has her paws full tonight. Workers at Zoo Atlanta were preparing for one cub birth. Well, imagine their surprise when two cubs showed up today.
HSU: And although the U.S. had never seen a successful twin birth before, panda keepers knew exactly what to do.
REBECCA SNYDER: To get them both to survive takes some work.
HSU: Rebecca Snyder is Zoo Atlanta's curator of mammals. She says they used a technique developed by their Chinese counterparts.
SNYDER: Periodically, we swap them.
HSU: When they were newborns, it happened every two hours. The Chinese had observed that panda mothers would not tend to two cubs at once. So in Atlanta, while Cub A was with mom, Cub B was kept warm in an incubator and they both thrived. Snyder says these kinds of discoveries like this have made a difference.
SNYDER: I do think the research has been a key reason that the captive population is doing so well now. Applying that to the wild population is not so easy.
HSU: So for all those hoopla over zoo births, there's still a lot of trepidation about pandas in the wild.
JONATHAN BALLOU: I think the breeding success is exciting and is really positive news. The message is we're not there yet.
HSU: Jon Ballou is population manager at the Smithsonian's National Zoo.
BALLOU: We don't know how many pandas are in the wild. The last survey showed 1600 in the wild. Sounds like a lot, but put 1600 people into a football stadium and it looks like a pretty small group right there, right? And so it's not enough.
HSU: Moreover, he says, their habitat is fragmented. It's not one big forest. Wild pandas live in scattered patches of forest. They cannot roam from one patch to another so they're even more exposed to environmental threats and inbreeding. Ballou's focus now is preserving as much genetic diversity as possible in the captive population. He wants to breed pandas that are, as a group, hardier and less vulnerable to disease.
BALLOU: Up until about four years ago, the focus was really on trying to create as many pandas as possible, which is important when you have a small population because you need to get a large. But as the population becomes larger, then you can focus more on genetic management.
HSU: Ballou came up with a formula to determine each panda's genetic value. Those with fewer relatives are more valuable than those with a lot of relatives. Each year, he crunches the numbers and travels to China to recommend matches. Now, there are pandas that Ballou won't recommend for breeding.
Take prolific Pan Pan, a 28-year old male who has fathered 32 cubs. Pan Pan's descendants, all 119 of them including Bao Bao, remember her?
They all share some genes. So matter how adorable, the birth of another Pan Pan descendent just isn't that interesting to Ballou.
BALLOU: If I know the mom and dad and are wild-caught animals and haven't bred before, that makes me the most excited, getting these genes into the population. Yes, and they're cute. Okay, that's kind of an added bonus.
HSU: In the mountains of Southwestern China, researchers have begun reintroducing captive pandas into the wild. But they've told Ballou they're not releasing the most genetically valuable ones yet, given what little is known about how they'll fare.
BALLOU: But I suspect in the future we will be talking about creating pairs to produce cubs to release into the wild.
HSU: Ones with stellar genes that he hopes will insure the long term survival of the species. Andrea Hsu, NPR News. Transcript provided by NPR, Copyright NPR.