Another prediction of this theory would be that naturally blind animals such as some moles would not need REM sleep or would have substantially less REM sleep.
I couldn't find any research in completely blind mammals, but in a mammal that has very poor eyesight "Cape mole rats sleep substantially less than other similarly sized terrestrial rodents but have a similar percentage of total sleep time occupied by REM sleep." https://www.researchgate.net/publication/301482322_Sleep_in_...
Seems like there is still a lot of scope for research on REM sleep in non-human species.
I think that this part of the article answers that
> those who are born blind (or who become blind early in life) don’t experience visual imagery in their dreams; instead, they have other sensory experiences, such as feeling their way around a rearranged living room or hearing strange dogs barking. This is because other senses have taken over their visual cortex.
The prediction would be that moles experience sounds in sleep, or smell, or touch, whatever their primary sense is.
