Failing eyesight, poor digestion, bad teeth, limbs no longer so limber: With captive giant pandas living longer than ever, the list of their physical and even emotional needs is growing. China, the pandas’ native home, is seeking to cater to those requirements with a special home for the old timers along with customized diets, exercise and other care aimed at improving their quality of life. “Of course we spend more energy taking care of old pandas,” said Xu Yalin, a panda keeper for 19 years at the China Conservation and Research Center for the Giant Panda Dujiangyan Base in the southwestern province of Sichuan. “Every day we need to interact with them closely and check their mental state,” Xu said. “We also examine their feces, the shape of it and so on. We worry more about the old pandas than the juveniles.” Pandas are considered old …