Fat-tailed dwarf lemurs are the only primates that hibernate - and their sleep patterns during hibernation are different from other animals that hibernate, like ground squirrels, which also hibernate at similar temperatures.
During hibernation, dwarf lemurs experience periods of rapid eye movement (REM) sleep at relatively high ambient temperatures, but no non-REM sleep. Ground squirrels, by contrast, experience only periods of non-REM sleep at high temperatures.
The sleep patterns observed confirm a link between ambient temperature while sleeping and metabolic rate.