The National Zoo’s panda cub Bei Bei (Photos)

Bei Bei celebrates his second birthday Aug. 22 with "panda-friendly" cake and several new toys. (Courtesy Smithsonian National Zoo)
Bei Bei celebrates his second birthday Aug. 22 with “panda-friendly” cake and several new toys. (Courtesy Smithsonian National Zoo) (Courtesy Smithsonian National Zo)
Bei Bei celebrates his second birthday Aug. 22 with "panda-friendly" cake and several new toys. (Courtesy Smithsonian National Zoo)
Bei Bei celebrates his second birthday Aug. 22 with “panda-friendly” cake and several new toys. (Courtesy Smithsonian National Zoo) (Courtesy Smithsonian National Zo)
Bei Bei celebrates his second birthday Aug. 22 with "panda-friendly" cake and several new toys. (Courtesy Smithsonian National Zoo)
Bei Bei celebrates his second birthday Aug. 22 with “panda-friendly” cake and several new toys. (Courtesy Smithsonian National Zoo) (Courtesy Smithsonian National Zo)
Bei Bei loves his bath time. The panda who turns 1 later this month is shown enjoying a hose-down by zoo workers in this video released on social media Aug. 3. (Courtesy Smithsonian National Zo)
Bei Bei, who is pictured here in January 2016, is growing daily and weighed 37 pounds as of March 17, 2016. Training is underway to teach him to come when called and to respond to commands to assist future veterinary check-ups. (Courtesy Smithsonian's National Zoo/Shellie Pick)
Bei Bei, who is pictured here in January 2016, is growing daily and weighed 37 pounds as of March 17, 2016. Training is underway to teach him to come when called and to respond to commands to assist future veterinary check-ups. (Courtesy Smithsonian’s National Zoo/Shellie Pick) (Shellie Pick/Smithsonian's National Zoo)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei with giant panda keeper Juan Rodriguez at the National Zoo Dec. 16, 2015. Bei Bei makes his public debut in January. (Shannon Finney Photography)
Bei Bei with giant panda keeper Juan Rodriguez at the National Zoo Dec. 16, 2015. Bei Bei makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January.  (Shannon Finney Photography)
Bei Bei with giant panda keeper Juan Rodriguez at the National Zoo Dec. 16, 2015. Bei Bei makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January.  (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January.  (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei and giant panda keeper Juan Rodriguez at the National Zoo Dec. 16, 2015. Bei Bei makes his public debut in January. (Shannon Finney Photography)
Bei Bei and giant panda keeper Juan Rodriguez at the National Zoo Dec. 16, 2015. Bei Bei makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography) (Shannon Finney Photography)
Bei Bei
In this photo taken Dec. 14, 2015, Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, is presented for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei
In this photo taken Dec. 14, 2015, Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, yawns while being presented for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei, Nicole MacCorkle, Laurie Thompson
In this photo taken Dec. 14, 2015, animal keeper Nicole MacCorkle, left, and biologist Laurie Thompson, right, attempt to look at the teeth of Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, in front of members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei, Nicole MacCorkle
In this photo taken Dec. 14, 2015, animal keeper Nicole MacCorkle stands near Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, as he sits in a small bin to be weighed for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei
In this photo taken Dec. 14, 2015, Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, falls asleep while being presented for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei, Stacey Tabellario
Animal keeper Stacey Tabellario holds Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, as he is presented to members of the media at the National Zoo in Washington, Monday, Dec. 14, 2015. Bei Bei will be making his public debut on January 16, 2016. (AP Photo/Andrew Harnik) (AP)
Bei Bei, Nicole MacCorkle
In this photo taken Dec. 14, 2015, animal keeper Nicole MacCorkle keeps a watchful hand near Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, as he is displayed for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei, Nicole MacCorkle
In this photo taken Dec. 14, 2015, animal keeper Nicole MacCorkle holds Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei, Stacey Tabellario
In this photo taken Dec. 14, 2015, animal keeper Stacey Tabellario holds Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, as he is presented to members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei
In this photo taken dec. 14, 2015, Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, is presented for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Bei Bei, Nicole MacCorkle, Stacey Tabellario
In this photo taken Dec. 14, 2015, animal keeper Nicole MacCorkle, accompanied by animal keeper Stacey Tabellario, left, carries Bei Bei, the National Zoo’s newest panda and offspring of Mei Xiang and Tian Tian, to be weighed for members of the media at the National Zoo in Washington. The youngest giant panda cub at the National Zoo is ready for his close-up. Bei Bei will make his public debut on Jan. 16. During an audience with a small news media contingent Monday, he was so relaxed that he fell asleep and drooled on an examination table. At nearly 4 months old, Bei Bei weighs more than 17 pounds and is gaining about a pound a week. He’s bigger than his older siblings were at the same age. (AP Photo/Andrew Harnik) (AP)
Panda cub Bei Bei takes his first steps at the National Zoo on Nov. 9, 2015. (Smithsonian National Zoo via YouTube) (AP)
Bei Bei weighed 9.5 pounds on Friday, Oct. 30. He's still working on building up his rear leg strength. (Courtesy National Zoo)
Bei Bei weighed 9.5 pounds on Friday, Oct. 30. He’s still working on building up his rear leg strength. (Courtesy National Zoo) (Courtesy National Zoo)
Bei Bei weighed in at 8.79 pounds Oct. 26. The National Zoo says that his mother, Mei Xiang, may have jaws that can crush bamboo, but she can be gentle when picking up Bei Bei in her mouth. And while she drags him across the floor, the smooth surface doesn’t hurt him. (Courtesy of the Smithsonian National Zoo via Instagram) (Courtesy National Zoo)
The National Zoo’s chief vet massages two of Bei Bei’s pressure points before a routine exam. (Courtesy National Zoo Twitter) (Courtesy National Zoo)
Bei Bei is doing just fine, according to a recent veterinarian's checkup. He's more attached to his mother than his big sister, Bao Bao, ever was. (WTOP/Kristi King)
Bei Bei is doing just fine, according to a recent veterinarian’s checkup. He’s more attached to his mother than his big sister, Bao Bao, ever was. (WTOP/Kristi King)
Keepers had a chance to weigh Bei Bei on Oct. 1. He now weighs 4.5 lbs. (2070g)—half a pound increase since he was weighed the previous week. Vets did a thorough check and took some body measurements. From Bei Bei’s head to the tip of his tail is 33 cm., just shy of 14 inches. His eyes are now partially open and teeth buds are developing! His ear canals are still closed but he should be able to hear some noises. (Juan Rodriguez, Smithsonian's National Zoo)
Keepers had a chance to weigh Bei Bei on Oct. 1. He now weighs 4.5 lbs. (2070g)—half a pound increase since he was weighed the previous week. Vets did a thorough check and took some body measurements. From Bei Bei’s head to the tip of his tail is 33 cm., just shy of 14 inches. His eyes are now partially open and teeth buds are developing! His ear canals are still closed but he should be able to hear some noises. (Juan Rodriguez, Smithsonian’s National Zoo) (Juan Rodriguez, Smithsonian's National Zoo)
Keepers had a chance to weigh Bei Bei on Oct. 1. He now weighs 4.5 lbs. (2070g)—half a pound increase since he was weighed the previous week. Vets did a thorough check and took some body measurements. From Bei Bei’s head to the tip of his tail is 33 cm., just shy of 14 inches. His eyes are now partially open and teeth buds are developing! His ear canals are still closed but he should be able to hear some noises. (Laurie Thompson, Smithsonian's National Zoo)
Keepers had a chance to weigh Bei Bei on Oct. 1. He now weighs 4.5 lbs. (2070g)—half a pound increase since he was weighed the previous week. Vets did a thorough check and took some body measurements. From Bei Bei’s head to the tip of his tail is 33 cm., just shy of 14 inches. His eyes are now partially open and teeth buds are developing! His ear canals are still closed but he should be able to hear some noises. (Laurie Thompson, Smithsonian’s National Zoo) (Laurie Thompson, Smithsonian's National Zoo)
Giant panda cub Bei Bei sneezes. As of Sept. 28, Bei Bei weighs 4 lbs. (Courtesy National Zoo YouTube) (Laurie Thompson, Smithsonian's National Zoo)
Michelle Obama, Peng Liyuan
First lady Michelle Obama and China’s first lady Peng Liyuan, reveal the name of the panda born at the Smithsonian’s National Zoo in Washington on Aug. 22, during a visit to the zoo in Washington, Friday, Sept. 25, 2015. The name is Bei Bei, which means “precious treasure.” It was chosen by both the Chinese and American first ladies. They were assisted by students from from Yu Ying Public Charter School, a Chinese-immersion, International Baccalaureate school. (AP Photo/Manuel Balce Ceneta) (AP)
Michelle Obama, Peng Liyuan
First lady Michelle Obama and China’s first lady Peng Liyuan, reveal the name of the panda born at the Smithsonian’s National Zoo in Washington on Aug. 22 to Mei Xiang, during a visit to the zoo in Washington, Friday, Sept. 25, 2015. The name is Bei Bei, which means “precious treasure.” It was chosen by both the Chinese and American first ladies. (AP Photo/Manuel Balce Ceneta) (AP)
Keepers had an opportunity to weigh the 4.5 week-old giant panda cub yesterday, Sept. 21, when Mei Xiang left her den to eat. He weighs 2.95 pounds (1,339 grams) and has now surpassed both of his older siblings in size when they were the same age. At 4 and-a-half weeks old, Bao Bao weighed approximately 2 pounds, and Tai Shan, weighed 2.6 pounds (1,181grams). (Courtesy Amy Enchelmeyer/Smithsonian’s National Zoo)
Keepers had an opportunity to weigh the 4.5 week-old giant panda cub Sept. 21 when Mei Xiang left her den to eat. He weighs 2.95 pounds (1,339 grams) and has now surpassed both of his older siblings in size when they were the same age. At 4 and-a-half weeks old, Bao Bao weighed approximately 2 pounds, and Tai Shan, weighed 2.6 pounds (1,181grams). (Courtesy Amy Enchelmeyer/Smithsonian’s National Zoo) (Courtesy Amy Enchelmeyer/Smithsonian’s National Zoo)
National Zoo keepers had an opportunity to weigh the 4.5 week-old giant panda cub Sept. 21, when Mei Xiang left her den to eat. He weighs 2.95 pounds and has now surpassed both of his older siblings in size when they were the same age. (Courtesy Smithsonian;s National Zoo)
National Zoo keepers had an opportunity to weigh the 4.5 week-old giant panda cub Sept. 21, when Mei Xiang left her den to eat. He weighs 2.95 pounds and has now surpassed both of his older siblings in size when they were the same age. (Courtesy Smithsonian;s National Zoo) (Courtesy Smithsonian;s National Zoo)
Keepers weighed the giant panda cub Sept. 14, when Mei Xiang left her den. He weighed 881.5 grams or 1.9 pounds. ( Erika Bauer/Smithsonian's National Zoo)
Keepers weighed the giant panda cub Sept. 14, when Mei Xiang left her den. He weighed 881.5 grams or 1.9 pounds. The cub also has much more distinct black-and-white markings. Zoo officials say the markings on his back closely resemble those of his father, Tian Tian. (Erika Bauer/Smithsonian’s National Zoo) (National Zoo)
On Sept. 13, the cub was visible on the panda cams and sleeping for much of the day, which is normal for a cub his age. Keepers noticed that he sleeps with his paw over his eyes, which is a position Tian Tian and Bao Bao frequently sleep in as well. Mei Xiang left the den four times for varying lengths of time: around 8 a.m. for five minutes, around 10 a.m. for 10 minutes, around 11 a.m. for five minutes, and around 4 p.m. for seven minutes. She also ate a pear for the first time since giving birth. Pears are one of her favorite food items.
On Sept. 13, the cub was visible on the panda cams and sleeping for much of the day, which is normal for a cub his age. Keepers noticed that he sleeps with his paw over his eyes, which is a position Tian Tian and Bao Bao frequently sleep in as well. Mei Xiang left the den four times for varying lengths of time: around 8 a.m. for five minutes, around 10 a.m. for 10 minutes, around 11 a.m. for five minutes, and around 4 p.m. for seven minutes. She also ate a pear for the first time since giving birth. Pears are one of her favorite food items. (Smithsonian's National Zoo)
Mei Xiang left the den around 9 a.m., about 30 minutes after keepers replenished food in her enclosure. She spent 15 minutes away from the cub, during which time he could be seen on the panda cam scooting around in circles. Keepers noted that the shape of his back saddle, the black marking on a panda’s back, resembles Tian Tian’s, his father.
Mei Xiang left the den around 9 a.m., about 30 minutes after keepers replenished food in her enclosure. She spent 15 minutes away from the cub, during which time he could be seen on the panda cam scooting around in circles. Keepers noted that the shape of his back saddle, the black marking on a panda’s back, resembles Tian Tian’s, his father. (Smithsonian's National Zoo)
Mei Xiang and her cub. (Smithsonian's National Zoo)
Mei Xiang and her cub on Sept. 11. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
Mei Xiang left the den about 30 minutes after keepers replenished food in her enclosure. From a distance, keepers observed that the cub’s eye slits are formed and will begin to open soon. A panda cub’s eyes are fully opened around 6 to 8 weeks of age. (Smithsonian's National Zoo)
Mei Xiang left the den about 30 minutes after keepers replenished food in her enclosure on Sept. 10. From a distance, keepers observed that the cub’s eye slits are formed and will begin to open soon. A panda cub’s eyes are fully opened around 6 to 8 weeks of age. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
Mei Xiang left the den around 8 a.m. She left again around 11 a.m. shortly after keepers placed fresh bamboo, biscuits and an apple in her enclosure. Keepers weighed the cub at 601.8 grams or 1.3 pounds. (Smithsonian's National Zoo)
Mei Xiang left the den around 8 a.m. on Sept. 9. She left again around 11 a.m. shortly after keepers placed fresh bamboo, biscuits and an apple in her enclosure. Keepers weighed the cub at 601.8 grams or 1.3 pounds. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
Mei Xiang left her den briefly allowing the panda team to weigh the cub. He was 601.8 grams or 1.3 pounds. (Meghan Murphy)
Mei Xiang left her den briefly allowing the panda team to weigh the cub. He was 601.8 grams or 1.3 pounds. Sept. 8. (Meghan Murphy) (Smithsonian's National Zoo/Mehgan Murphy)
On Saturday, Sept. 5, veterinarians and keepers took the opportunity to give the cub another quick checkup. He weighed 409.6 grams, which was 119 grams more than he weighed on Sept. 2. (Courtesy Smithsonian's National Zoo)
On Saturday, Sept. 5, veterinarians and keepers gave the cub a quick checkup. He weighed 409.6 grams, which was 119 grams more than he weighed on Sept. 2. (Courtesy Smithsonian’s National Zoo) (Courtesy Smithsonian's National Zoo)
Veterinarians also listened to his heart and lungs, which all sounded normal. (Courtesy Smithsonian National Zoo)
Veterinarians also listened to his heart and lungs, which all sounded normal. (Courtesy Smithsonian National Zoo) (Courtesy Smithsonian National Zoo)
The cub's eyes are still closed, which is normal. Cubs’ eyes generally open when they are 6 to 8 weeks old. (Courtesy Smithsonian National Zoo)
The cub’s eyes are still closed, which is normal. Cubs’ eyes generally open when they are 6 to 8 weeks old. (Courtesy Smithsonian National Zoo) (Courtesy Smithsonian National Zoo)
Mei Xiang and her cub Sept. 3. (Smithsonian's National Zoo)
Mei Xiang and her cub Sept. 3. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
Mei Xiang and her cub Sept. 2. (Smithsonian's National Zoo)
Mei Xiang and her cub Sept. 2. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
The National Zoo's giant panda Mei Xiang holds her newborn cub in their den Sept. 1 in this image captured by the zoo's panda cam. (Smithsonian's National Zoo)
The National Zoo’s giant panda Mei Xiang holds her newborn cub in their den Sept. 1 in this image captured by the zoo’s panda cam. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
In this screen shot, the surviving giant panda cub was left a lone for a bit while mom Mei Xiang took a break on Aug. 31, 2015. (Smithsonian's National Zoo)
In this screen shot, the surviving giant panda cub was left alone for a bit while mom Mei Xiang took a break on Aug. 31, 2015. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
The National Zoo's giant panda Mei Xiang holds her newborn cub in their den Aug. 28 in this image captured by the zoo's panda cam. (Smithsonian's National Zoo)
The National Zoo’s panda cam captured giant panda Mei Xiang and her newborn cub in their den Aug. 28. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
(Smithsonian's National Zoo)
In this screen grab, Mei Xiang and her newborn panda cub interact in their den at the Smithsonian's National Zoo. The surviving cub appears health with a plump tail and growing fur. It could be heard vocalizing and was "nursing appropriately" overnight from Aug. 26 into Aug. 27. Its smaller sibling died Wednesday. (Smithsonian's National Zoo)
In this screen grab, Mei Xiang and her newborn panda cub interact in their den at the Smithsonian’s National Zoo. The surviving cub appears health with a plump tail and growing fur. It could be heard vocalizing and was “nursing appropriately” overnight from Aug. 26 into Aug. 27. Its smaller sibling died Wednesday. (Smithsonian’s National Zoo) (Smithsonian's National Zoo)
The smaller of the two panda cubs drinks a special formula from a bottle in this Aug. 24 photo. The smaller cub had a birth weight of 86 grams. Its twin weighed 138 grams and is being cared for by mom, Mei Xiang. (Shellie Pick, Smithsonian's National Zoo)
The smaller of the two panda cubs drinks a special formula from a bottle in this Aug. 24 photo. The smaller cub had a birth weight of 86 grams. Its twin weighed 138 grams and is being cared for by mom, Mei Xiang. (Shellie Pick, Smithsonian’s National Zoo) (Shellie Pick, Smithsonian's National Zoo)
Zookeeper Shellie Pick cares for the smaller giant panda cub in an incubator overnight at the National Zoo, Aug. 24, 2015. Staff will weigh the cub, stimulate it so it will urinate and take its temperature. Staff are handling the smaller cub more intensively as mom Mei Xiang tends to the larger cub. (Heather Roberts, Smithsonian's National Zoo)
Zookeeper Shellie Pick cares for the smaller giant panda cub in an incubator overnight at the National Zoo, Aug. 24, 2015. Staff will weigh the cub, stimulate it so it will urinate and take its temperature. Staff are handling the smaller cub more intensively as mom Mei Xiang tends to the larger cub. (Heather Roberts, Smithsonian’s National Zoo) (Heather Roberts, Smithsonian's National Zoo)
National Zoo staff measure the second giant panda cub retrieved from Mei Xiang's den Aug. 23, 2015. (Devin Murphy, Smithsonian's National )
National Zoo staff measure the second giant panda cub retrieved from Mei Xiang’s den Aug. 23, 2015. (Devin Murphy, Smithsonian’s National ) (Devin Murphy, Smithsonian's National Zoo)
National Zoo veterinarians examine the first giant panda cub retrieved from mother Mei Xiang. (Becky Malinsky/Smithsonian's National Zoo )
National Zoo veterinarians examine the first giant panda cub retrieved from mother Mei Xiang. (Becky Malinsky/Smithsonian’s National Zoo ) (Becky Malinsky/Smithsonian's National Zoo )
National Zoo veterinarians examine the first giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian's National Zoo)
National Zoo veterinarians examine the first giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian’s National Zoo) (Pamela Baker-Masson, Smithsonian's National Zoo )
National Zoo staff examine the second giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian's National Zoo)
National Zoo staff examine the second giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian’s National Zoo) (Pamela Baker-Masson, Smithsonian's National Zoo)
National Zoo staff examine the second giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian's National Zoo)
National Zoo staff examine the second giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian’s National Zoo) (Pamela Baker-Masson, Smithsonian's National Zoo)
Giant panda Mei Xiang gives birth to a panda cub at the National Zoo Saturday, August 22, 2015. The zoo's panda team watched the birth on the Panda Cam. Mei Xiang's water broke about 4:32 p.m. and the first cub was born about 5:35 p.m. A second cub was born later that evening. (Smithsonian’s National Zoo)
Giant panda Mei Xiang gives birth to a panda cub at the National Zoo Saturday, August 22, 2015. The zoo’s panda team watched the birth on the Panda Cam. Mei Xiang’s water broke about 4:32 p.m. and the first cub was born about 5:35 p.m. A second cub was born later that evening. (Smithsonian’s National Zoo) (Smithsonian’s National Zoo)
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Bei Bei celebrates his second birthday Aug. 22 with "panda-friendly" cake and several new toys. (Courtesy Smithsonian National Zoo)
Bei Bei celebrates his second birthday Aug. 22 with "panda-friendly" cake and several new toys. (Courtesy Smithsonian National Zoo)
Bei Bei celebrates his second birthday Aug. 22 with "panda-friendly" cake and several new toys. (Courtesy Smithsonian National Zoo)
Bei Bei, who is pictured here in January 2016, is growing daily and weighed 37 pounds as of March 17, 2016. Training is underway to teach him to come when called and to respond to commands to assist future veterinary check-ups. (Courtesy Smithsonian's National Zoo/Shellie Pick)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei with giant panda keeper Juan Rodriguez at the National Zoo Dec. 16, 2015. Bei Bei makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January.  (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January.  (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January.  (Shannon Finney Photography)
Bei Bei and giant panda keeper Juan Rodriguez at the National Zoo Dec. 16, 2015. Bei Bei makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei is shown to the media at the National Zoo Dec. 16, 2015. He makes his public debut in January. (Shannon Finney Photography)
Bei Bei
Bei Bei
Bei Bei, Nicole MacCorkle, Laurie Thompson
Bei Bei, Nicole MacCorkle
Bei Bei
Bei Bei, Stacey Tabellario
Bei Bei, Nicole MacCorkle
Bei Bei, Nicole MacCorkle
Bei Bei, Stacey Tabellario
Bei Bei
Bei Bei, Nicole MacCorkle, Stacey Tabellario
Bei Bei weighed 9.5 pounds on Friday, Oct. 30. He's still working on building up his rear leg strength. (Courtesy National Zoo)
Bei Bei is doing just fine, according to a recent veterinarian's checkup. He's more attached to his mother than his big sister, Bao Bao, ever was. (WTOP/Kristi King)
Keepers had a chance to weigh Bei Bei on Oct. 1. He now weighs 4.5 lbs. (2070g)—half a pound increase since he was weighed the previous week. Vets did a thorough check and took some body measurements. From Bei Bei’s head to the tip of his tail is 33 cm., just shy of 14 inches. His eyes are now partially open and teeth buds are developing! His ear canals are still closed but he should be able to hear some noises. (Juan Rodriguez, Smithsonian's National Zoo)
Keepers had a chance to weigh Bei Bei on Oct. 1. He now weighs 4.5 lbs. (2070g)—half a pound increase since he was weighed the previous week. Vets did a thorough check and took some body measurements. From Bei Bei’s head to the tip of his tail is 33 cm., just shy of 14 inches. His eyes are now partially open and teeth buds are developing! His ear canals are still closed but he should be able to hear some noises. (Laurie Thompson, Smithsonian's National Zoo)
Michelle Obama, Peng Liyuan
Michelle Obama, Peng Liyuan
Keepers had an opportunity to weigh the 4.5 week-old giant panda cub yesterday, Sept. 21, when Mei Xiang left her den to eat. He weighs 2.95 pounds (1,339 grams) and has now surpassed both of his older siblings in size when they were the same age. At 4 and-a-half weeks old, Bao Bao weighed approximately 2 pounds, and Tai Shan, weighed 2.6 pounds (1,181grams). (Courtesy Amy Enchelmeyer/Smithsonian’s National Zoo)
National Zoo keepers had an opportunity to weigh the 4.5 week-old giant panda cub Sept. 21, when Mei Xiang left her den to eat. He weighs 2.95 pounds and has now surpassed both of his older siblings in size when they were the same age. (Courtesy Smithsonian;s National Zoo)
Keepers weighed the giant panda cub Sept. 14, when Mei Xiang left her den. He weighed 881.5 grams or 1.9 pounds. ( Erika Bauer/Smithsonian's National Zoo)
On Sept. 13, the cub was visible on the panda cams and sleeping for much of the day, which is normal for a cub his age. Keepers noticed that he sleeps with his paw over his eyes, which is a position Tian Tian and Bao Bao frequently sleep in as well. Mei Xiang left the den four times for varying lengths of time: around 8 a.m. for five minutes, around 10 a.m. for 10 minutes, around 11 a.m. for five minutes, and around 4 p.m. for seven minutes. She also ate a pear for the first time since giving birth. Pears are one of her favorite food items.
Mei Xiang left the den around 9 a.m., about 30 minutes after keepers replenished food in her enclosure. She spent 15 minutes away from the cub, during which time he could be seen on the panda cam scooting around in circles. Keepers noted that the shape of his back saddle, the black marking on a panda’s back, resembles Tian Tian’s, his father.
Mei Xiang and her cub. (Smithsonian's National Zoo)
Mei Xiang left the den about 30 minutes after keepers replenished food in her enclosure. From a distance, keepers observed that the cub’s eye slits are formed and will begin to open soon. A panda cub’s eyes are fully opened around 6 to 8 weeks of age. (Smithsonian's National Zoo)
Mei Xiang left the den around 8 a.m. She left again around 11 a.m. shortly after keepers placed fresh bamboo, biscuits and an apple in her enclosure. Keepers weighed the cub at 601.8 grams or 1.3 pounds. (Smithsonian's National Zoo)
Mei Xiang left her den briefly allowing the panda team to weigh the cub. He was 601.8 grams or 1.3 pounds. (Meghan Murphy)
On Saturday, Sept. 5, veterinarians and keepers took the opportunity to give the cub another quick checkup. He weighed 409.6 grams, which was 119 grams more than he weighed on Sept. 2. (Courtesy Smithsonian's National Zoo)
Veterinarians also listened to his heart and lungs, which all sounded normal. (Courtesy Smithsonian National Zoo)
The cub's eyes are still closed, which is normal. Cubs’ eyes generally open when they are 6 to 8 weeks old. (Courtesy Smithsonian National Zoo)
Mei Xiang and her cub Sept. 3. (Smithsonian's National Zoo)
Mei Xiang and her cub Sept. 2. (Smithsonian's National Zoo)
The National Zoo's giant panda Mei Xiang holds her newborn cub in their den Sept. 1 in this image captured by the zoo's panda cam. (Smithsonian's National Zoo)
In this screen shot, the surviving giant panda cub was left a lone for a bit while mom Mei Xiang took a break on Aug. 31, 2015. (Smithsonian's National Zoo)
The National Zoo's giant panda Mei Xiang holds her newborn cub in their den Aug. 28 in this image captured by the zoo's panda cam. (Smithsonian's National Zoo)
In this screen grab, Mei Xiang and her newborn panda cub interact in their den at the Smithsonian's National Zoo. The surviving cub appears health with a plump tail and growing fur. It could be heard vocalizing and was "nursing appropriately" overnight from Aug. 26 into Aug. 27. Its smaller sibling died Wednesday. (Smithsonian's National Zoo)
The smaller of the two panda cubs drinks a special formula from a bottle in this Aug. 24 photo. The smaller cub had a birth weight of 86 grams. Its twin weighed 138 grams and is being cared for by mom, Mei Xiang. (Shellie Pick, Smithsonian's National Zoo)
Zookeeper Shellie Pick cares for the smaller giant panda cub in an incubator overnight at the National Zoo, Aug. 24, 2015. Staff will weigh the cub, stimulate it so it will urinate and take its temperature. Staff are handling the smaller cub more intensively as mom Mei Xiang tends to the larger cub. (Heather Roberts, Smithsonian's National Zoo)
National Zoo staff measure the second giant panda cub retrieved from Mei Xiang's den Aug. 23, 2015. (Devin Murphy, Smithsonian's National )
National Zoo veterinarians examine the first giant panda cub retrieved from mother Mei Xiang. (Becky Malinsky/Smithsonian's National Zoo )
National Zoo veterinarians examine the first giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian's National Zoo)
National Zoo staff examine the second giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian's National Zoo)
National Zoo staff examine the second giant panda cub retrieved from mother Mei Xiang. (Pamela Baker-Masson, Smithsonian's National Zoo)
Giant panda Mei Xiang gives birth to a panda cub at the National Zoo Saturday, August 22, 2015. The zoo's panda team watched the birth on the Panda Cam. Mei Xiang's water broke about 4:32 p.m. and the first cub was born about 5:35 p.m. A second cub was born later that evening. (Smithsonian’s National Zoo)

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