Scientists are scrambling to learn why the distinctive black patches around the eyes of giant pandas are fading away in some animals.
The patches are the bears’ most distinctive trait, and there’s evidence to suggest they help them recognize one another.
In addition to the fur loss, some of the 12 bears are suffering from ulcers around their eyes, according to Luo Qinglin, an ophthalmologist who examined the pandas. The affected animals have been quarantined at the base, which is home to more than 150 pandas (link in Chinese) in China’s Sichuan province.
Luo began studying the pandas’ symptoms along with dermatologist Ran Yuping in January, after photos of several bears with the condition were shared on Chinese social media.
In January, the research center issued a statement (link in Chinese) saying 10 pandas were infested with mites (it later increased the number to 12). Pandas are sensitive to mites, it said, and the parasites have caused fur loss in the animals before. Sichuan’s humid environment makes it easy for mites and bacteria to thrive.
But when the affected pandas were given drugs known to repel mites, the treatment proved ineffective. The base said it was considering using another drug.
In 2013, a pair of panda siblings in a Hangzhou zoo also experienced shedding around the eyes. The zoo said mites likely caused the “whitening” of their dark patches. The condition did not prove fatal, as in 2016 the bears were transferred back to their birthplace (link in Chinese), the Chengdu breeding base.