Phil Ridges and Emmie
Media playback is unsupported on your device
Video

How to tickle a gorilla

Scientists are studying how animals respond to being tickled in a bid to find out how laughter evolved.

Here, Phil Ridges, head keeper for the ape palace in Port Lympne Wild Animal Park in Kent, explains how Emmie the gorilla reacts when she is tickled.

Go to next video: Pygmy owl squeaks when tickled