According to welfare group Animals Asia, the video went viral in China, where people were moved by the sight of the tigers displaying such worry for their companion.
"The video clearly shows the tigers empathizing with the plight of their peer," Dave Neal, animal welfare director for Animals Asia, said in a statement. "They know he is in trouble and needs help and they want to give it to him. They are torn between their training, with its threat of violence, and their natural sympathy for another tiger in danger."
China's circuses in particular have long been dogged by animal welfare concerns - a 2016 investigation into several Chinese circuses showed lions and other animals being beaten and kept in tiny, filthy cages between performances.
But the problem is hardly limited to China. Across the world - including in the U.S. - circus cats are trained using fear-based methods: They're often whipped and shouted at, as the apex predators are unlikely to obey their trainers, let alone be safe to work with, unless they're "broken in." Performing elephants are trained using bullhooks - point instruments trainers use to jab at the animals and make them obey.