The San Diego Zoo giant pandas have been star attractions there and worldwide on the Internet for almost two decades. However, a cancer diagnosis and old age may force the zoo and its panda fans to face the end of the highly successful breeding efforts in San Diego, at least for the foreseeable future.
Gao Gao, the patriarch of the zoo’s giant pandas, had surgery Wednesday to remove his right testicle, which was found to have a cancerous tumor. The matriarch, Bai Yun, is also being watched closely. She would normally be in estrous this time of year, but is not showing signs of it. As both pandas age, it looks like the zoo’s highly successful run of a new cub nearly every other year may be over, at least with this parenting pair as the San Diego Zoo panda program faces and deals with the cancer and plans for their old age.
The zoo’s veterinarians are hopeful that Gao Gao will recover. There is no sign of cancer in his other testicle, but they are not sure about his breeding future.
Gao Gao, who was found badly injured in the wild in China, is estimated to be 24 years old, which is approaching old age for a panda in captivity (pandas in the wild typically live to be 14 to 20 and in captivity up to 30 years old). PandaCam fans readily recognize when he is on camera, because he is missing part of an ear, which was one of his initial injuries.
Gao Gao’s cancerous tumor was a seminoma, which is typically not aggressive or likely to metastasize. But the bear has a heart condition that concerns vets.
Also this week, the zoo officials have basically concluded that Gao Gao’s mate is not likely to go through another breeding cycle. They believe the panda, 22-year-old Bai Yun, is in her species’ equivalent of menopause. A San Diego Zoo resident since 1996, Bai Yun gave birth to the six cubs born there, the last five from successful mating with Gao Gao. (Her first cub was the result of artificial insemination.)
Only four zoos in the U.S. have giant pandas, which are all are on loan from China. Under the agreement, once any cubs are old enough they are sent to China to further breeding and conservation efforts there. All but the youngest, 20-month-old Xiao Liwu, of the cubs born to Bai Yun have gone to China. Her eldest, Hua Mei, was the first surviving giant panda born in the US. Since going to China in 2004, she has had nine cubs of her own, including three sets of twins.
The panda is an endangered species. There are only 1,600 giant pandas are believed to exist. As a wild species, their survival is threatened by habitat destruction as China’s population has grown, a low reproductive rate, shortages of bamboo plants (which is their primary food), besides their natural predators.
China began its efforts to save the panda in 1957. Then, in 1989, China’s Ministry of Forestry and the World Wildlife Fund developed a plan for reducing human activities in the panda habitat areas, conserving the bamboo forests, and maintaining captive populations of pandas. China now has 60 panda reserves with some natural corridors connecting some of the reserves to let the panda populations roam and mingle. The five now-adult bears born in San Diego Zoo panda program and their offspring are in Chinese reserves, while their parents face cancer and old age and their younger, recently weaned brother continues to grow.
By Dyanne Weiss