External genitalia in bears doesn't develop until the bear is several months old. The best, and most reliable, way to determine a bear cub's sex is through DNA analysis. Scientists from the Smithsonian Conservation Biology Institute's Center for Conservation Genomics obtain the DNA from a gentle cheek swab during a veterinary exam.
Giant Panda Cub FAQs
Have questions about panda cubs? Check out some of the most commonly asked questions to learn more about the early stages of a giant panda's life.
Any baby born to Mei Xiang and Tian Tian belongs to China, and the Zoo will send the offspring to China at about age 4, so it can become part of the breeding population there.
In December 2009, the Zoo announced that Tai Shan would be sent to China in early 2010, per the Zoo's agreement with the China Wildlife Conservation Association. He left the Zoo for China on Feb. 4, 2010.
Mei Xiang's second surviving cub, Bao Bao, also departed for China on Feb. 21, 2017.
On Sept. 25, 2015, the First Lady of the United States and the First Lady of the People's Republic of China named the cub Bei Bei.
Bears in the wild, including giant pandas, give birth in small dens. In China's Wolong Reserve, pandas make their dens in large hollow conifer trees, with a diameter of about 3 feet. Where there aren't any trees, pandas den in caves with a little bedding of twigs. They stay in these dens for about the cub's first 100 days.
Zoo keepers strive to recreate these surroundings for Mei Xiang. She always has access to her larger enclosures, though for the first few months of the cub's life she will spend the vast majority of her time in the den with him. She will occasionally venture out to eat, drink, urinate and defecate. Those trips will become increasingly longer as the cub grows.
In January of 2013, in anticipation of the breeding season, keepers rearranged Mei Xiang's den, including shifting the angle of the bars, so that keepers would have more direct access to Mei Xiang and her cub while they are resting in the nest area. The old bars were recycled, making the renovations not only a little greener, but also a little less overwhelming for Mei Xiang. It was as if the "furniture" was simply rearranged one day.
Why are the lights always on in the den? Why is the cam sometimes in color and sometimes in black and white?
It is usually dark in Mei Xiang's den, as it would be in a wild bear's den, but the cams have infrared and low-light capabilities, which allow her and the cub to be visible to cam viewers. This is also why the cam usually looks black and white. When the keepers turn on the lights, the cam shows up in color, except for the bears, of course, who are always black and white.
When bears give birth in the wild, the mothers spend several months denned up with their cubs. Their focus during this time is nurturing and protecting their cubs, rather than eating. Scientists have observed giant panda mothers in the wild go as long as one month without eating or drinking. Like other bears, pandas seem to go through a metabolic shift during the summer months, when their food intake drops up to 75 percent. This coincides with when pandas den and produce cubs, like other bear species. One difference to note is that other bears fast for several months during hibernation.
The cams are turned off periodically when keepers enter the den to assess the cub and Mei Xiang.
Newborn giant panda cubs are born very tiny and delicate. When Mei Xiang licks the cub, she is stimulating him to urinate and defecate. Cubs are unable to urinate and defecate on their own in the first weeks of life.
Mei Xiang keeps her cub tucked under her arm, or under her chin much of the time. Panda cubs are unable to regulate their own body temperature, so Mei Xiang cradles the cub closely to her body to keep him or her warm. She moves the cub by picking it up in her mouth.
The cub squeals when it wants to nurse or be repositioned. Regular loud squeals are signs of a healthy cub.
Sometimes it appears as though Mei Xiang is breathing heavily. She is breathing on her cub to keep him in a warm and humid environment.
Scientists from the Smithsonian Conservation Biology Institute's Center for Conservation Genomics used DNA analysis to determine the sire of Mei Xiang's cub Bei Bei. It showed that Tian Tian is the sire.
SCBI scientists artificially inseminated Mei Xiang April 26 and 27, 2015, with fresh semen from Tian Tian and frozen-then-thawed semen from Hui Hui (h-WEI h-WEI). Hui Hui lives in China, but was one of the best genetic matches for Mei Xiang.
In China, it is standard practice to use sperm from more than one male when artificially inseminating a female. This increases the chances of fertilization and viable embryos.
In 2015, Hui Hui, a 10-year-old panda living in China, was one of the best genetic matches for Mei Xiang. An SCBI scientist and Rubenstein Fellow, Caitlin Burrell, brought a frozen sample of Hui Hui's semen back from China with her in April 2015. It was placed in SCBI's cryopreservation bank at the Zoo.
Male pandas are not involved in the care of their cubs. Fathers and cubs may never encounter each other in the wild.
No. In the wild giant pandas are solitary and separate from their mothers around the age of 18 months. Keepers strive to mimic those conditions at the Zoo.
The panda team prepares for a panda cub birth based on behaviors they see, hormones they monitor and ultrasounds. Smithsonian Conservation Biology Institute scientists look for a rise in Mei Xiang's urinary progesterone. A rise indicates that she would give birth to a cub or experience the end of a pseudopregnancy in 30 to 50 days. The panda team then begins monitoring Mei Xiang 24 hours a day and attempts ultrasounds.
When the panda team conducts a health check they have a list of things to accomplish. They will measure the cub's body weight, assess hydration, take a body measurement, check the oral cavity, check the umbilicus, check the genitalia and rectal area, palpate the abdominal cavity, take a fecal culture, take the rectal temperature, listen for a heartbeat and lung sounds, and collect any urine produced.
Mei Xiang's den was rearranged in 2015 to allow the panda team to get closer to her and a cub for health checks, or to retrieve the cub. There is a barrier in the den, which keeps members of the panda team safe when they enter the den with Mei Xiang and a cub. Mei Xiang and the keepers are never on the same side of the barrier.
When the panda team removes a cub from the den for a health check, a minimum of two keepers are always present. No more than three keepers enter the den at the same time. One keeper focuses on retrieving the cub, and another keeper monitors Mei Xiang. Keepers offer Mei Xiang bamboo, juice, sugarcane or honey water while they retrieve the cub during the first weeks of his life. When Mei Xiang begins leaving the cub more frequently for longer periods of time, keepers can retrieve the cub from the den while Mei Xiang is eating in the adjacent enclosure.
They will pick the cub up with a gloved hand.
Li Guo, the giant panda keeper visiting from China, supported the Zoo's panda team after Bao Bao was born in 2013, and returned in 2015 for Bei Bei's birth. He is a giant panda cub nursery expert. Li has extensive experience caring for cubs.
Yes, Mei Xiang gave birth to two cubs Aug. 22, 2015. The first was born at 5:35 p.m. and the second was born at 10:07 p.m. The panda team immediately implemented the Zoo's Giant Panda Twin Hand-Rearing Protocol after they observed Mei Xiang having difficulty caring for both cubs. Developed from the experience and success of Chinese partners and other zoos, the hand-rearing protocol provided the panda team with several strategies to manage twin cubs. Swapping the cubs between mother and hand-rearing is a proven method that enables Zoo staff to best care for twins in the event that the mother cannot manage two cubs, which was the case with Mei Xiang.
When swapping the cubs became difficult, the panda team had in their possession the smaller cub, which was losing weight, needed calories and energy, and was at risk if he remained away from Mei Xiang for a prolonged period of time. The cub's best option for survival was to receive supplemental feedings via bottle and tube, but both techniques present risks. The team witnessed some regurgitation of food during one feeding, so the cub was started on antibiotics as a preventative measure.
The smaller cub was with Mei Xiang from about 2 p.m., Aug. 25, until the morning of Aug. 26. When the panda team swapped the cubs, they assessed the cub and had concerns, because he had not increased in weight, appeared weaker and exhibited possible respiratory issues. He died shortly after 2 p.m. Based on the necropsy's gross findings, Zoo pathologists and veterinarians determined the most likely cause of death to be complications associated with aspiration of food material into the cub's respiratory system resulting in the development of pneumonia.
The cub was male, fraternal twin to the larger cub, and sired by Tian Tian.
No. Mei Xiang cared for whichever cub was in the den with her. But female giant pandas struggle to care for more than one cub at once. That is why the panda team was swapping cubs, so Mei Xiang could take care of one at a time.
Several people who watch the panda cam have mentioned seeing a mouse that occasionally runs through Mei Xiang's den. The Giant Panda building is a secure, dry area protected from the elements, so it is inherently attractive to all sorts of opportunistic rodents. The food that the giant pandas eat also attracts mice. The Zoo has a team of pest management specialists who work with keepers to reduce and control the visiting rodent population throughout the Zoo. And although keepers diligently work to exclude them, rodents are amazingly smart animals (something you can learn more about at the Zoo's Think Tank exhibit). The pest management team has even observed rodents outsmarting traps by flinging them against walls, and then making off with the bait. In addition, the Zop refuses to use pesticides in its panda exhibit, which makes the challenge of controlling the rodent population a little more difficult.
Of course, much as the Zoo's team admires rodents' cognitive abilities, they would still prefer them not to be in with the animals. Fortunately, Mei Xiang is a 200-pound bear with strong instincts to protect her cub. No mouse --however clever or cunning-- poses a serious threat to her or her cub.