Do dogs have bad dreams/nightmares?

[GusGus]

I am wondering because Gus was asleep on the bed and I was watching TV next to him. He started making his usual noise/movements when he's 'dreaming' but he did that and shot his head up and started yelping.. then looked at me like he was frightened. I moved immediately so he could put his head on my lap and I petted him and whispered calming words..but it really worried me. He seems fine now. I checked and there's no way he could have hurt himself. Nothing on the bed, neither of is moved before it happened..

[huntergreen]

i am convinced they dream, so nightmares wouldn't be an unreasonable stretch.

[GusGus]

I just have no idea what would cause him to yelp like that. He honestly looked scared. I could see it in his eyes and especially in his ears.

[MichaelE]

I'm convinced that they dream. I've seen too many human-like actions from sleeping dogs that I think were dreaming not to believe it.

Little yelps, moans, legs twitching, mouths moving, etc. I just don't see how they couldn't be dreaming.

[arycrest]

I've always felt that dogs dream. I've read that they have REM sleep patterns similiar to those humans have during dream periods.