Dogs probably dream.
They move through sleep stages that resemble those seen in humans, including REM sleep.
Dogs enter REM sleep
REM stands for rapid eye movement.
During this stage, brain activity becomes relatively active while most large skeletal muscles are inhibited.
Humans report vivid dreams especially often after REM sleep.
Dogs also enter REM.
That shared sleep architecture is one major reason scientists think dreaming is not uniquely human.
Why do dogs twitch and make sounds?
Small movements can break through normal muscle inhibition.
A sleeping dog may twitch paws, flick ears, move the face, whimper, or make small barking sounds.
Those movements are consistent with dreaming.
They do not tell us exactly what the dream contains.
A paw twitch does not scientifically prove there is a squirrel involved.
What would dogs dream about?
We cannot ask them for a report.
Research in other mammals suggests sleeping brains can reactivate patterns linked with waking experiences.
It is reasonable to think dog dreams draw from movement, smells, social interactions, play, and familiar places.
Should you wake a twitching dog?
Usually not.
Mild twitching is normal.
Suddenly waking a sleeping dog can startle it.
Letting the dog wake naturally is generally better unless there is a safety concern.
Is dog dreaming related to human dreaming?
Yes.
Humans also experience dreams that can feel extremely real because the sleeping brain remains highly active.
The plot is probably different.
The basic sleep biology has a lot in common.
Dogs probably dream.
We just do not get the morning review.
And that’s the short explanation.
Related explanations: Why do dreams feel real?, Why do dogs circle before lying down?, and Why do dogs tilt their heads?