Table 3.

Changes in amount of REM sleep during early development in animals.

Animals		REM Sleep	References
Animals born with advanced maturation	Chimpanzee	22.4% of TST < 1 year, 16.0% between 1 and 2 years, and 13.1% above 2 years old.	[135]
	Rhesus monkey	31% of TST at birth, a brief increase to 43% at day 7, then, gradually decreases to 35% at day 30, to 27% between 9 and 13 months, and 19% (15% to 23%) at 2 years old.	[136,137,138,139,140]
	Sheep	60% of TST at 120 days of gestation, 45% at birth, 18% at day 7, and 14.71% at day 15.	[23,141]
Animals born with immaturity	Kitten	In its first days, 50% in REM sleep (100% of TST) and 50% in wakefulness. 50% of total recording time (TRT) on day 7, and 20% on day 35.	[18,142,143,144,145,146,147]
	Rat	72% of TRT in the first week, 58% at day 11, 8% at day 30.	[16,18]
	Mouse	40% of TRT in the first week, 6% at day 19.	[148]
	Rabbit	75% of TST at birth, 33% on day 14, and 10% on day 23.	[149]