It’s a boy … cub.
The 6-week-old giant panda born at the Smithsonian’s National Zoo is a male, scientists confirmed Monday, and the third male cub of the oldest giant panda mother in the U.S. to have a successful pregnancy.
“We are so excited for another male cub. Each cub is unique, and we can’t wait to get to know this cub and his distinct personality. It is wonderful that we can share this joyful event with our guests near and far,” said Michael Brown-Palsgrove, curator of the Asia Trail at the National Zoo.
Zoo veterinarians swabbed the cub’s cheek for DNA analysis during its first veterinary exam on Sept. 19. Because male and female cubs look physically similar at birth, a genetic test is the most accurate way to determine sex.
Scientists at the Smithsonian Conservation Biology Institute sequenced a short fragment of the zinc finger protein gene using the cub’s cheek swab and found that the cub has DNA sequences for both X and Y chromosomes, indicating the cub is a male.
The giant panda team revealed the sex of the cub with a video posted online featuring a painting made by male giant panda Tian Tian, the cub’s father, which had blue paint strokes.
The panda cub appears to be healthy and strong, said zoo veterinarians, who conducted a brief exam of the cub on Oct. 1. The cub weighed 3.6 pounds and measured 14 inches from the nose to the tip of the tail.
When 22-year-old giant panda Mei Xiang gave birth to the cub in August, she became the oldest panda in the U.S. and the second-oldest in the world to have a successful pregnancy. She is also the first panda at a zoo in the U.S. to give birth with artificial insemination using only frozen sperm.
Scientists and veterinarians artificially inseminated Mei Xiang on March 22 with frozen sperm from Tian Tian, who turned 23 in late August.
Mei Xiang gave birth to three surviving cubs: Tai Shan in July 2005, Bao Bao in August 2013, and Bei Bei in August 2015. All cubs were moved to China when they were 4 years old as part of a cooperative breeding agreement with the Asian country.
Mr. Brown-Palsgrove said the cub’s ears should open completely in the next few days and his eyes should be fully open around 8 weeks of age. Giant pandas’ ear canals usually start to open 31 to 50 days after birth, the zoo said.
“He will begin to experience the sights and sounds of his environment. He should become stronger and more coordinated in his independent movement around the den,” Mr. Brown-Palsgrove said.
Per tradition, the zoo will name the cub 100 days after his birth, in a ceremony at the end of November.
For days after the cub’s birth, Mei Xiang didn’t leave her den and kept her newborn close. Giant panda mothers in the wild spend much of their cubs’ first month tucked in a small den, where they feed and cradle the newborn and keep it warm.
At 2 weeks old, the panda cub’s black markings started to become visible. At 3 weeks old, the cub had its first neonatal exam.
At 1 month old, the cub began growing into the panda’s “signature plump,” the zoo said, which means it is starting to regulate its own body temperature and allowing Mei Xiang to leave her den more often. As the cub develops, Mei Xiang will be able to leave for longer periods.
The giant panda house at the National Zoo is currently closed to provide peace and quiet for Mei Xiang and her cub. The Asia Trail, which includes giant panda viewing, is temporarily closed to visitors for repaving of walkways.
The zoo reopened in July with entry requirements and other COVID-19 health precautions.
• Shen Wu Tan can be reached at stan@washingtontimes.com.
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