REM sleep?

Since there is no change in posture, it is difficult to determine the beginning and end of a REM sleep episode on the basis of behavior in elephants (no EEG has been recorded).

Nevertheless, many signs of REM sleep can be observed: twitches of the fore- and hind limbs, tail, tusk and ears, vocalizing and irregular breathing. Their eyes are very small, and eye-movements cannot be determined unambiguously even in the newborn (Photos: day one after birth; Emmen Zoo, Holland).