Table 1.

Period of MD and Darkness (with modifications) for each animal

Cat	Period of MD (postnatal days)	Period of darkness (postnatal days)	Modifications
C150, C153, C156	30–37	37–47
C151, C152, C157	30–37	93–103
C304	30–37	94–104
C301	30–37	94–104	1/4 h L/D
C300	30–37	94–104	1/2 h L/D
C303	30–37	94–99
C155	30–37	71–81
C169	30–37	92–97
C192, C166	7–37	37–47
C190	7–37	37–47	1/2 h L/D
C191	7–37	37–42
C165	7–37	93–103
C220, C222	7–43	43–53
C219	7–43	92–102
C221	7–56	113–123

L/D, light/dark.