The dragon sleeps tonight

Reptile Sleep![Figure][1] Monitoring the brains of sleeping reptiles, like this bearded dragon, reveals the ancient origins of slow-wave and REM sleep. PHOTO: STEPHAN JUNEK/MAX PLANCK INSTITUTE FOR BRAIN RESEARCH Most animal species sleep, from invertebrates to primates. However, neuroscientists have until now only actively recorded the sleeping brains of birds and mammals. Shein-Idelson et al. now describe the electrophysiological hallmarks of sleep in reptiles. Recordings from the brains of Australian dragons revealed the typical features of slow-wave sleep and rapid eye movement (REM) sleep. These findings indicate that the brainstem circuits responsible for slow-wave and REM sleep are not only very ancient but were already involved in sleep dynamics in reptiles. Science , this issue p. [590][2] [1]: pending:yes [2]: /lookup/doi/10.1126/science.aaf3621