This is the moment an annoyed Beluga whale ‘snapped' at tourists who kept knocking on aquarium's glass in Taiwan.

Footage shows the extremely sociable marine mammal staring at a group behind the glass at the National Museum of Marine Biology and Aquarium in Pingtung county on June 18.

The adults were busy filming the sea creatures while their children tapped on the glass to call the whale's attention.

However, the whale's reaction amused the tourists as it appeared to scold the woman.

Mom-of-two Wang Shi Ting said: 'I took my children to watch the beluga whale and they loved it. I did not expect it appear annoyed and snap at us. It was friendly of course, but its reaction was funny.'

Despite amusing the tourists, scientists believe that the beluga whale opening its mouth and posturing is a sign of aggression as the behaviour has been observed in a lot of animals in captivity before under similar circumstances.