Giant Panda in Hong Kong Gives Birth to Twins, Becomes World’s Oldest First-Time Panda Mom

One day before she turned 19, Ying Ying welcomed one female and one male cub at the theme park Ocean Park

A theme park in Hong Kong is celebrating a doubly special delivery!

Giant panda Ying Ying gave birth to Hong Kong's first set of twin cubs, making her the world's oldest first-time panda mom, according to a press release from Ocean Park. She and partner Le Le welcomed a female and a male cub on Thursday, Aug. 15, just one day before she turned 19, which is the equivalent of about 55 in human years.

"This birth is a true rarity, especially considering Ying Ying is the oldest giant panda on record to have successfully given birth for the first time," Paulo Pong, chairman of Ocean Park Corporation, said in statement, also thanking the animals' care and veterinary team.

Ying Ying and Le Le have lived at Ocean Park since 2007.

Related: Giant Panda at Theme Park in South Korea Gives Birth to Country's First Set of Panda Twins

Per the release, the proud panda mom first began displaying pregnancy-like symptoms at the end of July, including decreased appetite, increased rest time and changes in her hormonal levels. The pregnancy was confirmed via ultrasound on Aug. 11.

On Aug. 14, Ying Ying exhibited signs of active labor such as increased activity and irritability. Her water broke around 10 p.m. that same day. "As a first-time mother, Ying Ying was understandably nervous throughout the process. She spent much of her time lying on the ground and twisting," the park said.

After more than five hours of labor, the female cub made her arrival at 2:05 a.m. on Aug. 15, weighing in at 122 grams (4.3 ounces). The male twin followed at 3:27 a.m., weighing 112 grams (3.95 ounces).

The park said the newborns are "currently very fragile and need time to stabilize, especially the female cub who has a lower body temperature, weaker cries and lower food intake after birth." Both cubs remain under "24-hour intensive care" and will not make their public debut for a few months.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories. 

The park promised to provide updates on the baby animals via a dedicated Instagram account. A post on Friday, Aug. 16, featured a photo of one of the tiny cubs being fed from a bottle. Another photo showed the twins in an incubator together.

Related: Panda in French Zoo Gives Birth to Female Twin Cubs

A third post on Friday shared video footage of Ying Ying tending to her cubs. "The birth of the giant panda babies is the most nervous thing for mother Ying Ying," the caption read in part. "When the babies [were] born and [made their] first cry, it immediately awakened Ying Ying's maternal love."

Giant pandas have a “notoriously difficult time reproducing, especially as they age," the park said. According to Pandas International, a female panda only has one estrous cycle per year, in the spring, for two to seven days, and she is only fertile for 24 to 36 hours. As there are often substantial difficulties in getting female and male pandas to mate, scientists often rely on artificial insemination procedures.

Additionally, panda pregnancy is not easy detectable. Female pandas can experience pseudopregnancy, where they exhibit the same symptoms and behaviors as pregnant pandas but are not actually pregnant. Panda fetuses are typically too small to be seen on an ultrasound, so pregnancy is often not confirmed until late into the gestation period or after the baby is born.

For more People news, make sure to sign up for our newsletter!

Read the original article on People.