A small baby spends a lot of sleeping time in a stage of sleep called REM (rapid eye movement). (rollercoaster.ie)
A newborn baby spends more than 80 % of total sleep time in REM, while adults only spend around 20 - 25 % of their time asleep in REM. (easybabylife.com)
Total sleep time increased by about 10 minutes at the nine - month follow - up. (sciencedaily.com)