Is it possible to establish that dogs dream?

Sleeping dogs exhibit a lot of behavioural sings of dreaming :
they make running motions
wag their tails
lick their lips and so on.
Dogs exhibit rapid -eye movement (REM) sleep,which in humans is strongly associated with dreaming.And during REM sleep,dogs exhibit heightened
brain activity , just humans do.
The best explanation for all this is that dogs dream.

well maybe this puppy is not a good example