A Malayan sun bear stands upright as it interacts with visitors at Hangzhou Zoo in Zhejiang province. [Photo provided to China Daily]

Hangzhou Zoo has rejected rumors that some of its bears are people wearing costumes after videos of a Malayan sun bear standing on its hind legs — and looking uncannily human — went viral on social media, triggering widespread speculation.

In a statement written from the perspective of the 4-year-old sun bear named Angela, the zoo in the capital of Zhejiang province said that people didn't quite understand the species, which is known to mimic human postures such as standing and walking on its hind legs.

"I am a bear, a sun bear," said the statement posted on Sunday on the zoo's official WeChat account. "My name is Angela," it said.

Videos of Angela, standing upright on a rock inside her enclosure and waving at visitors, went viral soon after it was uploaded on microblogging site Sina Weibo on July 27. In addition to the sun bear's curious antics, the loose folds of fur on its back fueled speculation that a human might be masquerading as a bear.

The zoo denied such suggestions and said on Saturday that it would be impossible for a person to survive in a heavy bear costume when the maximum temperature in Hangzhou was hovering around 40 C.

The WeChat statement, written from the sun bear's point of view, said on Sunday: "I got a call after work yesterday from the director of the zoo asking me if I was being lazy and found a human to take my place. ... That was totally uncalled for. I take the business of interacting with my visitors quite seriously."

Angela's antics and her sudden fame on social media have increased the number of visitors to the zoo. "Once the videos went viral, we started receiving over 20,000 visitors a day," Jiang Zhi, deputy director of the zoo, told Tide News, a portal based in Zhejiang.

The Malayan sun bear, also called the honey bear, is the world's smallest bear species. The average adult weighs 55 kilograms and when standing, is approximately 1.5 meters tall, Jiang said.

Unfortunately, the sun bear's population in the wild is dwindling fast, and it is classified as a first-class national protected animal in China. The average life span of the species is 24 years.

Angela, who arrived in Hangzhou from another zoo in Zhejiang three years ago, has just stepped into adulthood. She shares her living space and meals — mostly seasonal fruits, worms and milk — with her male companion, Dalu. The two are almost inseparable, according to their handlers.

The zoo has already prepared a maternity room, hoping to welcome cubs later this year or in 2024.

As for Angela's humanlike posture, Jiang said that all bears can stand on their hind legs to view distant objects, or when they sense a potential enemy. Sun bears are excellent tree climbers and inquisitive by nature, and have a greater tendency to stand on their hind legs, he added.