Reptiles share sleep patterns with mammals and birds after all

http://www.eurekalert.org/pub_releases/2016-04/aaft-rss042516.php

Public Release: 28-Apr-2016
Reptiles share sleep patterns with mammals and birds after all
American Association for the Advancement of Science

A new study reveals that the sleep patterns previously thought exclusive to mammals and birds - REM and slow-wave sleep patterns - are also found in reptiles. The results shake up our understanding of the evolution of sleep. Amniotes are a group of tetrapod vertebrates comprising reptiles, birds and mammals. Because slow-wave sleep (SWS) and rapid eye movement sleep (REMS) are thought to be exclusive to mammals and birds, it's believed that these sleep states evolved twice after mammals and birds diverged from reptiles. However, results by Mark Shein-Idelson et al. now reveal SWS and REM sleep patterns in the Australian bearded dragon, Pogona vitticeps, suggesting that the sleep states may have evolved in a common ancestor of all amniotes, more than 300 million years ago.

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