The four moon bears, aged 5-7, were transferred to the Vietnam Bear Rescue Center in stable health. A representative of the center said the transfer was the result of a shift from using wild animals to domesticated ones in circus performances.

The bears would undergo a 30-day quarantine period, have their health checked and diseases treated before they're allowed to integrate with their peers at the center.

Tuan Bendixsen, Vietnam Director of animal welfare organization Animals Asia, which oversees the bear sanctuary, said 15 circuses in Vietnam have completely stopped using wild animals in their performances, while other circuses are in the process of following suit.

This is the second time Animals Asia has received bears coming from the Central Circus. Two other bears also left the circus in 2019, and are now living well at the Vietnam Bear Rescue Center.

The center is home to 186 bears now. There are around 600 other bears still kept in captivity in Vietnam, and a few hundred roaming in the wild.

Vietnam is home to both the moon bear and the sun bear, species listed as vulnerable by the International Union for the Conservation of Nature.

Many bears are kept in cages to extract their bile, believed to be a remedy for various ailments in Vietnam. Although commercial bear bile extraction was banned in 2005, farms already having the animals were allowed to keep them.

Under current Vietnamese law, violation of wildlife protection regulations is punishable by up to seven years in jail.