Sun bears are nocturnal, and with curved claws, naked soles (great name for a rock band), and a 100 lbs body weight, they are terrific climbers. They like small vertebrates, fruit, and, of course, honey.
Young sun bears are playful and curious and do well in captivity. But they become markedly cranky and bad-tempered as they grow old. What with the wrinkles and the hypnotic stare, icy stare, and the poor temperament when old, I'm thinking my grandpa might be a sun bear. That would account for all his tree climbing and honey cravings.