Table 2.

Mean ± SEM of cortisol in milk among high-, middle-, and low-ranking macaque mothers at early and peak lactation (1 month and 3–4 months postpartum, respectively) and the calculated change (Δ) per day between the 2 time points

Rank	N	Concentration (nmol/L)
		Early	Peak	Δ per day
High	39	175±13	169±15	−0.08±0.2
Middle	36	176±15	177±14	0.02±0.2
Low	33	176±16	172±21	−0.12±0.2