According to local reports, the 8-month-old boy's mother was changing his diaper inside the Guiyang Qianling Wildlife Park, when one of the zoo's monkeys suddenly pounced on the child and ripped off a chunk of his genitals.
Qianling Park is known for allowing its substantial monkey population to roam free.
Signs posted by the park's management warn guests not to feed the animals, but officials believe the monkey may have mistaken the boy's private parts for food.
CCTV says another visitor successfully retrieved the baby's severed testicle, but that the monkey quickly snatched it from his hand and ate it before it could be tackled.
Though doctors said the child's injuries are not life-threatening, they expressed concern that his reproductive abilities may have been irreparably damaged.
A different Chinese zoo was mocked last month for trying to pass off a dog as a full-size African lion. This incident, of course, is much, much worse.