Maternal behavior is related to prepartum urinary estradiol levels in red-bellied tamarin monkeys

Abstract

This is the first study in a primate, the red-bellied tamarin ( Saguinus labiatus), to demonstrate a correlation between urinary estradiol during late pregnancy and postpartum infant-directed behavior. Females were defined as good ( N=6 ) or poor ( N=6 ) mothers, and were selected so that both groups contained 3 females with and 3 without prepubertal experience with infants. Females with prepubertal experience of infants were defined as good or poor mothers if 2 or less than 2 infants survived one week, respectively; females without such experience were defined as good or poor mothers if at least 1, or 0 infants survived one week, respectively. Five of the six good mothers had 2 surviving infants; 10 of the 13 infants of poor mothers died at day 0. Prepartum urinary total estradiol concentrations were constant in good mothers (5-4 weeks prepartum: 32.29±3.65 μg/mg creatinine; 1 week prepartum: 33.76±5.02 μg/mg CR.; p > 0.98), but declined significantly in poor mothers (5-4 weeks prepartum: 38.34±7.07 μg/mg Cr.; 1 week prepartum: 18.35±4.72 μg/mg Cr.; p<0.0004). At 1 week prepartum, estradiol was significantly higher in good mothers ( p<0.03). When analysed separately, only good and poor mothers without prepubertal experience of infants had significantly different urinary estradiol concentrations. In the 2-hour postpartum period, good mothers spent more time lick-cleaning ( p<0.02), carrying and nursing infants; poor mothers rubbed off clinging infants more, their infants spent less time being carried ( p<0.03), and apparently starved because they had no opportunity to suckle.