World Smile Day is celebrated on May 8 every year. But smiling is not just a human's unique expression, but can also be seen on the face of wild animals. (Photos: Chinanews.com)

Staff at a zoo in Southwest China’s Chongqing have taken photos of smiling wild animals. Have a look at their cute smiles!

This photo shows the smiling face of a gorilla.

This photo shows the smiling face of a white tiger.

This photo shows the smiling face of a lesser panda.

This photo shows the smiling face of an elephant.

This photo shows the smiling face of a dolphin. (Compiled by Xu Zheqi)