CINCINNATI -- It’s official: The Cincinnati Zoo and Botanical Garden’s cuteness factor just went up another notch with the announcement of its newest baby red panda. On June 25, mother Lin gave birth to the cub, which is the 86th born at the facility.

“We don’t know what the sex is because we don’t have hands on until the cub is 8 weeks old,” said senior Wildlife Canyon keeper Lissa Browning. The zoo leads the world in red panda births for the fulgen Styani subspecies. “Visitors can see it when it comes out in September -- by then it’s very big and fluffy. When they’re born they’re white and the black starts to come in and then the red comes in last."

While the Cincinnati Zoo boasts great success with red panda breeding, Browning said that’s not the case with other institutions. She said it’s difficult enough to determine if the panda’s pregnant, let alone when or if the female will actually give birth. She said the species is one of many cold-weather carnivores that experience delayed embryo implantation, meaning once pregnant the tiny embryo may float around for weeks or months before attaching to the uterine wall. As a result, it may take the female anywhere from 90 to 160 days to give birth.

Bei Lei, one of the Cincinnati Zoo's red pandas, looks down from her climate-controlled den.

“And they can have pseudo pregnancies as well,” she said. “So we weigh them every week and they can get fluid in the uterus so you think maybe they’re pregnant and then you come to find out they’re not.”

To help unlock the mystery, researchers from the zoo’s center for Conservation and Research of Endangered Wildlife (CREW) undertook studying red panda reproductive research four years ago.

CREW’s reproductive physiologist, Dr. Erin Curry, collaborated on the research detailed in a paper discussing their findings and recently published in Zoo Biology. Through analysis of stool samples to measure hormones and ultrasound on multiple potentially pregnant females, Curry accurately predicted the birth of Lin’s last cub in August 2015, which was appropriately named Dr. Erin Curry in honor or the scientist.

“The reason I became interested in red pandas -- well not only because they’re cute and trainable -- but reproductively they’re very similar to polar bears, which is my species of interest,” Curry said. “So they’re both seasonal breeders, they only breed a specific time of year and they’re both induced ovulators so they have to breed in order for ovulation to occur.”

In domestic animals like cats and dogs, Curry said that once they breed, 65 days later you get puppies or kittens -- but that’s not the case with red pandas. To better hone in on the species’ due dates, she said they studied potentially pregnant females adding different colored glitter to their food so they could easily identify their fecal samples in the yard. She said Browning then took on the task of training the girls to accept ultrasound.

Senior Wildlife Canyon keeper Lissa Browning (left) and CREW's Dr. Erin Curry worked to unlock the mystery of red panda pregnancy.

“So Lissa was able to train all these little red pandas to voluntarily stand for an ultrasound examination, which is not an easy feat,” she said. “They’re wild animals and it’s not just the ultrasound probe, but we have to put a ton of ultrasound jelly on their abdomen to penetrate -- and they have really, really thick fur so it usually requires three handfuls of ultrasound jelly.”

After ordering as specially built T-stand, Browning said she eased the girls into the process by using props to simulate the ultrasound equipment and water instead of the jelly. She said her first candidate female, LiWu, quickly took the process in only two weeks because she’s highly food-motivated. As no previous information existed on administering ultrasound to red pandas, Browning said it was a bit of a learning curve to identify the exact location of the bladder and uterus.

“So for two years we ultrasounded LiWu, and then we added another female in that we were pretty sure was pregnant and I trained her in the same way, and we were able to see a fetus on her. So it kind of just snowballed after that,” she said.

In addition to aiding in identifying false pregnancies, Curry said through ultrasound they were able to monitor changes to the uterine diameters in four different pregnant females. She said the process allowed them to catalogue useful measurements for other institutions to follow and ultimately led to her being able to identify the due date for her furry namesake. She said in the future they hope to identify a biomarker in stool samples that will ultimately identify pregnancy.

“So we’re trying to create some sort of index that other people could use to try and figure out if and when their animals might give birth,” Curry said.

In addition to the research, Browning credits some of their breeding success to denning females during the summer from May to September. As the species resides in cooler climates in the wild, she said potentially expectant mothers seem to be more relaxed indoors in their climate-controlled dens. She said the girls have a number of different indoor dens to choose from to give birth or move their cubs around if they desire.

“Other institutions give them access outdoors so they can come and go as they please and sometimes that can be stressful and the mother won’t carry cubs or can lose cubs,” she said. “But we’ve just had great luck and great pandas.”

Curry also gave a shout out to the zoo’s team effort.

“I don’t know what we do here that makes everything work so well, but a combination of management and nutrition and good pandas -- it’s probably mostly the pandas,” she said.

Unfortunately the success of breeding in institutions hasn’t changed the perils the animals face in the wild. The species was just upgraded from threatened to endangered, Browning said, with fewer than 10,000 remaining in their native lands of Nepal and China. She said with the crackdown on rhino horn and the ivory trade, more red panda pelts have appeared on the black market. But she says there are ways to help through zoo adoption/donation programs, the red panda network and red panda rangers for kids.

You can also purchase a red panda painting by LiWu at the gift shop. All proceeds go to the red panda network and to the red panda species survival plan.