File photo: The survey by pet food firm Wagg showed similarities between animals and humans. Picture: Xinhua/Sunil Sharma

London - A quarter of dog owners have seen their pets sleepwalking. And 99 percent said their dogs had vivid dreams – involving them barking, growling or even trying to run.

Dr Robert White-Adams, a vet and dog expert, said the survey by pet food firm Wagg showed similarities between animals and humans.

"It is difficult to prove, but the behaviour exhibited by our pets while they sleep convinces us that they are dreaming," he said.

"In humans, sleep talking is an activity that is strongly linked to the dream phases of the sleep cycle."