Can dogs have nightmares?

I was woken up in the middle of the night by grunts and growls from Drake. He was laying right next to me and kept pressing his body against me. I knew he was alseep. I tried pet his back hoping it would wake him up. I didn't want to startle him awake so he wouldn't unconsciously snap or something. Then he let out a yelp and started whimpering. Finally, I said, Drake! Come on boy! And got up from bed. He woke up and followed me out to the kitchen. He drank water and I had some juice and then we went to bed. Drake cuddled with me all night and was very restless.

I found his behaviour after I woke him up very odd. Drake is not as needy as his mommy is. But it was like he needed to sleep next to me last night. He laid with his head on my stomach and I petted it. If I stopped, he would lift his head and look at me. He would only rest it back if I started petting again.

Wonder what that was all about.