A pacific white-sided dolphin cub and its mother sport in Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province, July 2, 2019. Three pacific white-sided dolphin cubs made their first public appearance on Tuesday in Zhuhai. The three cubs, born in May of 2019, are all male. (Photo: Xinhua)

Pacific white-sided dolphins are seen in Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province, July 2, 2019. Three pacific white-sided dolphin cubs made their first public appearance on Tuesday in Zhuhai. The three cubs, born in May of 2019, are all male. (Photo: Xinhua)

Staff members feed and perform routine health checks to pacific white-sided dolphins in Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province, July 2, 2019. Three pacific white-sided dolphin cubs made their first public appearance on Tuesday in Zhuhai. The three cubs, born in May of 2019, are all male. (Photo: Xinhua)

Pacific white-sided dolphins are seen in Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province, July 2, 2019. Three pacific white-sided dolphin cubs made their first public appearance on Tuesday in Zhuhai. The three cubs, born in May of 2019, are all male.(Photo: Xinhua)

Pacific white-sided dolphins are seen in Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province, July 2, 2019. Three pacific white-sided dolphin cubs made their first public appearance on Tuesday in Zhuhai. The three cubs, born in May of 2019, are all male.(Photo: Xinhua)