A US man who fell down a crevice and was trapped for up to six days without food or water was discovered by a dog out walking with its owner.

Ramon Llamas had taken his one-year-old dog, Mole, out for their usual hike in California's Mount Rubidoux, east of Los Angeles, on Monday morning when the dog began whimpering and tugging on its owner's leg towards some rocks off the main track.

When Mr Llamas followed Mole to the rocks, he saw something moving inside a crevice and two eyes staring back at him.

Mr Llamas initially believed it was an animal - possibly a coyote - but was stunned to hear the voice of a man speak back to him.