Cute giant pandas now can be seen in zoos around the world besides their homeland China thanks to the success of captive breeding programs. The global population of captive-bred giant pandas reached 600 in 2019, which was unimaginable many years ago.
In 1936, Ruth Harkness, an American fashion designer, brought the first live giant panda to the United States, later creating a panda craze that swept the world. Back in the 1930s, there were only eight captive giant pandas. The Brookfield Zoo in Chicago was the first one to raise giant pandas in captivity.
Ruth Harkness with Su-Lin, the first giant panda cub brought to the United States. /VCG
The captive breeding program of giant pandas in China started in 1953, and it progressed slowly at first. The flowering and withering of large bamboo areas in southwest China's Sichuan Province in the 1970s and 1980s made the task of breeding giant pandas more urgent. Two major institutions, China Research and Conservation Center for the Giant Panda founded in 1983 and Chengdu Research Base of Giant Panda Breeding built in 1987, shouldered the task.
Unlike the wild giant pandas that move around the forest a lot to search for food, giant pandas in captivity tend to slack off as they live in a small area and a large amount of food is provided to them every day. Gradually, they get lazy and lose interest in mating. Therefore, many captive giant pandas need artificial insemination to breed cubs, but it's not easy.
Giant panda ''Yang Yang'' (R) mates with giant panda ''Su Shan'' at the Bifengxia base of the China Conservation and Research Center for the Giant Pandas in Ya'an City, southwest China's Sichuan Province, April 14, 2016. /VCG
From 1987 to 1994, only 14 giant pandas were bred at Chengdu Research Base of Giant Panda Breeding and their health conditions were not great. Hou Rong, director of Chengdu Research Base of Giant Panda Breeding, has gone through the long and stressful journey of breeding giant pandas by artificial insemination.
The first challenge in front of her is to collect the semen. In the past, some male giant pandas would have blood in their stool after semen collection. Hou studied the structure of male giant panda's genital tract by watching their B-mode ultrasound images and specimen, and put her hand inside the rectum to feel the actual position.
She then came up with a way of collecting semen by massaging the rectum and using smoother electroejaculation. The new method not only worked, but also caused less harm to pandas. The male giant pandas soon regained their appetite after semen collection.
Hou Rong worked at Chengdu Research Base of Giant Panda Breeding in southwest China's Sichuan Province. /Credit to Chengdu Research Base of Giant Panda Breeding
After collecting the semen, researchers have to cryopreserve or freeze it for artificial insemination because female giant pandas only ovulate once a year. Here comes the second challenge. The thawed sperm motility was pretty low in the past, meaning that it's hard to get the female pregnant.
Hou tried various ways to store the semen by adjusting the concentration of cryoprotectant, the speed of cryopreservation and some other factors, and finally found a way that can increase the sperm motility to 60 percent. In 2005, the number of giant pandas in captivity at the base was 46, but it's still far away from the goal of 300.
A newly-born giant panda at Chengdu Research Base of Giant Panda Breeding in southwest China's Sichuan Province. /VCG
What's more worrisome is the health of captive-bred giant pandas. In 2005, about one third of them had diarrhea from time to time. They need infusions to get nutrition and gain weight. These giant pandas that have a relatively low weight and rough fur get the nickname of "jiangmao." Hou Rong and researchers at the base were clueless in the beginning.
They guessed it might be the problem with either the water, food or disease. After analyzing all breeding materials and data, they found the culprit was the food. Back then, the staff would feed captive giant pandas with food rich in animal protein to add nutrition. However, the good intention went awry.
After removing meat, eggs and other similar items from the diet, the weight of captive giant pandas all increased, even the adults who were believed to be unable to gain more weight.
A giant panda cub at Chengdu Research Base of Giant Panda Breeding in southwest China's Sichuan Province. /VCG
By the end of 2019, the number of captive-bred giant pandas at the Chengdu Research Base of Giant Panda Breeding has increased from only six in the 1980s to 206. The global population of pandas in captivity also surpassed 600, smashing the original goal of 300.
With this number of giant pandas in captivity, its population can be self-sustained and genetic diversity of over 95 percent can be retained for 100 years. The assiduous efforts made by researchers like Hou Rong paid off and saved giant pandas from extinction.
About "Lost then Found" series:
Many species on Earth went extinct because of environmental change, evolutionary problems, habitat loss or humans. The disappearance of species from Earth is ongoing, but some species are lucky to survive thanks to conservation efforts made by humans. In this series, CGTN will guide you through the journey of saving these creatures from extinction.
For more:
Giant Panda National Park 2: Guardians of giant pandas
(Cover image designed by CGTN's Li Yueyun.)
(If you want to contribute and have specific expertise, please contact us at nature@cgtn.com.)