Internet users questioned whether the zoo’s bears were real after photos circulated showing one standing upright on slender hind legs.
“Because of the way they stand, some people online question whether they are ‘humans in disguise,’” the newspaper Hangzhou Daily said.
Sun bears are the size of large dogs, standing at most 1.3m tall on their hind legs, compared with up to 2.8m for grizzlies and other species, according to the zoo.
Other Chinese zoos have been accused of trying to pass off dogs dyed to look like wolves or African cats, and donkeys painted to look like zebras.