Corona Daily 348: Panda and the Pandemic

The National Zoo in Washington D.C. has two giant pandas. Tian Tian (pronounced Tee-YEN Tee-YEN) and Mei Xiang (May-SHONG). Pandas’ life expectancy is 14-20 years. Mei is 22 years old. An endangered species, fewer than 2000 pandas exist in the world, all of them owned by China. China leases them to zoos like the National Zoo for $1 million per annum. Any cubs born in the zoo must be sent back to China on their fourth birthday.  

The National Zoo shut on 7 March. And Mei began to ovulate on 14 March. Normally, the zoo must collect her urine without her knowing about it to test her hormone levels. On 22 March, her hormone levels peaked, during lockdown.

In 2004, when Mei hit puberty, the Zoo staff had tried to mate her with Tian to breed naturally.  Female pandas are in heat only once a year, and only for a day or two. Pandas lack the skill, if not desire, to mate properly. Believe it or not, male pandas are given Viagra, and shown “panda porn”. The sex education didn’t help either of them. Mei always lay flat on her stomach, and Tian had no idea what to do.

Artificial insemination was the only choice, not an easy one. One team needed to sedate Tian to extract fresh semen. Another team would anesthetize Mei and deposit the semen in her uterus.  Mei successfully delivered three cubs, Tai Shan (2005), Bao Bao (2013), and Bei Bei (2015).

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So far, only one panda has delivered in her 20s. In March, when Mei started her high pitched chirp, the few staff members present were at a loss. Taking fresh semen from Tian was impossible, that team was at home. The zoo decided to use the freezer. It used 800 million frozen, five year old sperm. The probability of Mei becoming pregnant was less than 1%.

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In Pandas, phantom pregnancies are common. So are stillbirths and miscarriages. A female panda weighs around 230 pounds. The cub is incredibly tiny, 1/900th the size of the mother, weighing only 3-4 ounces. Sometimes the fetus gets unexpectedly absorbed into the mother’s body, this is called resorption. When twins are born, the mother nurses only one of them, letting the other die. Zoo staff tries to play tricks by swapping the other cub every few hours. This doesn’t always succeed. Mei has lost two cubs in the past.

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On 14 August, Mei gave a signal suggesting she may be pregnant. There have been many false signals over the years. She was fed honey water; in exchange she allowed an ultrasound. Currently, the National zoo doesn’t allow visitors to the Panda House, but anyone can watch live action on PandaCam. The website crashed that day. For an ageing matriarch panda to be pregnant was a miracle. Unlike in humans, panda pregnancy can be seen only close to the delivery, because of the tiny fetus.

On Friday, 21 August at 06.35 pm, Mei successfully delivered a single cub. Its gender will be known after a few months. Cubs are generally named after 100 days. The American media celebrated the addition to the zoo, a rare dose of good news.

Tian, whose five year old semen was used, seemed quieter than usual, probably because he could hear the cries of the baby. But both in the wild, and in the zoo, male pandas have no role in raising the cub. While Mei was busy nursing the cub inside the den, Tian was busy outside, enjoying his breakfast.

Ravi