The first giant panda cub born at the National Zoo in five years turned a month old this week, and zoo veterinarians say the cub appears healthy and strong.
Zoo staff conducted their first veterinary exam of the panda cub Saturday, when its mother, Mei Xiang (may-SHONG), stepped out of her den.
Veterinarians were able to measure and weigh the cub, check its vital signs and take a quick swab of the cub’s cheek for DNA analysis to use later to determine its sex, which they should know in the next few weeks.
The cub weighed in at 952 grams, just over 2 pounds, and measured 34 centimeters, or 13.4 inches, from nose to tail. Veterinarians listened to the cub’s heart and lungs, tested its suckle reflex and moved all four limbs to test muscular development.
“Watching this little one grow under the care of its amazing mother, Mei Xiang, over the past four weeks has been a bright spot in the lives of all who follow their story,” the zoo said Monday in an update.
While the cub’s eyes are still closed, the left eye is not closed as tightly and could open soon. Newborn giant pandas generally open their eyes between 6 and 8 weeks of age, according to the zoo.
At 100 days after its birth, the zoo will hold a naming ceremony for the cub, per tradition.
The 22-year-old Mei Xiang (pronounced “may SHONG”) gave birth to her cub Aug. 21 around 6:30 p.m., becoming the oldest panda in the U.S. to have a successful pregnancy. Zoo staff described the cub as pink and tiny, the size of a stick of butter, when it was born.
Mei Xiang previously gave birth to three surviving cubs: Tai Shan (pronounced “tie-SHON”) on July 9, 2005, Bao Bao (pronounced “BOW BOW”) on Aug. 23, 2013 and Bei Bei (pronounced “BAY BAY”) on Aug. 22, 2015.
For the three cubs, zoo keepers artificially inseminated Mei Xiang with semen from 23-year-old giant panda Tian Tian since the pandas have been unable to breed naturally. But for this cub, the staff inseminated Mei Xiang with frozen sperm instead of collecting fresh semen from Tian Tian so that zoo staff could socially distance amid the COVID-19 pandemic.
For days after the cub’s birth, Mei Xiang didn’t leave her den, keeping her newborn close to her. During much of the cub’s first month of life, giant panda mothers in the wild spend much of that time tucked in a small den feeding, cradling and keeping the newborn warm.
At two weeks old, the panda cub’s black markings started to become visible. At three weeks old, zoo staff were able to conduct its first neonatal exam of the cub.
The cub is now growing into the panda’s “signature plump,” the zoo said, which means it is starting to regulate its own body temperature, allowing Mei Xiang to leave her den more often. As the cub gets older, Mei Xiang will be able to leave for longer periods of time.
The giant panda mother has followed a similar eating pattern with all of her cubs. With Tai Shan, she ate bamboo for the first time since giving birth on Day 16. For Bao Bao and Bei Bei, she ate for the first time on Day 14. For this cub, she started eating bamboo on Day 15, according to the zoo.
Last week, Mei Xiang left her den up to three times a day and for up to 18 minutes to eat and drink. The zoo staff give her two species of bamboo and leaf eater biscuits to eat. She also has juice, water and apples and pears — her favorite fruits — given to her twice daily from staff in the enclosure adjacent to her den.
Mother bears in the wild spend several months in dens with their cubs after giving birth, focusing on nurturing and protecting their newborns, according to the National Zoo. Scientists have observed wild giant panda mothers going as long as one month without eating or drinking.
The panda house will be closed to the public for months. The Smithsonian’s National Zoo reopened July 24 with safety protocols after shutting down due to the pandemic. The zoo is open from 8 a.m. to 4 p.m., and entry passes are required.