A zoo in eastern China has denied suggestions that some of its bears were people dressed in costume after videos of a Malayan sun bear standing on its hind legs -- and looking uncannily human -- went viral, fueling rumors and conspiracy theories on Chinese social media.

In a statement written from the perspective of a sun bear named "Angela", officials from Hangzhou zoo said that people "didn't understand" the species.

"I'm Angela the sun bear -- I got a call after work yesterday from the head of the zoo asking if I was being lazy and skipped work today and found a human to take my place," the statement read.

"Let me reiterate again to everyone that I am a sun bear -- not a black bear, not a dog -- a sun bear!"

In videos shared on the popular Chinese microblogging site Weibo, a sun bear was seen standing upright on a rock and looking out of its enclosure.

Many Weibo users noted the animal's upright posture, as well as folds of loose fur on its behind -- making the bear look somewhat odd and fueling speculation that a human imposter might be masquerading in its place.

It might sound like an implausible gambit. But zoos in China have courted public ridicule in the past for trying to pass off pets like dogs as wild animals.

In 2013, a city zoo in the central Henan province angered visitors by trying to pass off a Tibetan Mastiff dog as a lion. Visitors who had approached the enclosure expressed shock when they heard the "lion" bark.

Visitors at another Chinese zoo, in Sichuan province, were shocked to discover a golden retriever sitting in a cage labeled as an African lion enclosure.

World's smallest bears under threat

Native to the tropical forests of Southeast Asia, sun bears are the world's smallest bear species. Adult bears stand at heights of up to 70 centimeters tall (28 inches) and weigh between 25 to 65 kilograms (55 to 143 pounds), experts say.

They do not hibernate and are also characterized by amber colored crescent shaped fur patches on their chests and long tongues which help them extract honey from bee hives -- earning them the name "beruang madu" (honey bear) in Malaysia and Indonesia.

Their numbers in the wild are at threat by poachers and deforestation, declining by 35% over the past three decades, according to conservation groups like the World Wildlife Fund (WWF) and Bornean Sun Bear Conservation Center (BSCC) in Sabah, Malaysia.

Sun bears are listed as vulnerable by the International Union for Conservation of Nature (IUCN).