Yaya is a 20 yrs old senior panda, who has dental problems that makes difficulty in biting and chewing.
Insufficient Bamboo Farm
Both pandas appear malnourished compared to pandas in any given zoo worldwide. The cause might be insufficient bamboo and inadequate quality + type. Memphis Zoo claims that their 11 acres of bamboo farm is main source of bamboo for BOTH pandas, yet research shows a 17 acres farm may be sustainable for only ONE panda.
Selling Bamboo to Other Zoo
2013-2016, Memphis Zoo won the bid to sell their bamboo to Toronto Zoo, and later to Calgary Zoo. Since 11 acres is already insufficient for two pandas, it no doubt created more bamboo shortage for YaYa and LeLe. Which is why in 2016 Memphis Zoo asked residents to donate bamboo.
2020-now, Memphis Zoo temporarily paused exhibitions. Through the 24-hr panda cam, fans found YaYa and LeLe locked in the den for up to 18 hours a day. Since pandas need big spaces, this caused serious mental distress called 'stereotypical behaviour' (e.g. Netherlands Zoo constructed 36000 sq.ft of space for their 2 pandas to move FREELY and AT WILL )
LACK OF ENRICHMENTS
Enviromental & Nutritional
YaYa and LeLe rarely receive supplements other than bamboo (e.g. carrots, pumpkins, corn, wheat etc). This creates nutrients imbalance, on top of the already insufficient bamboo.
Nor do they receive environmental enrichments such as self-serving toy feeders that stimulate foraging interests.