Murdering Mommy Monkeys May Provide Insight Into Postpartum Depression
Scientists are rushing to understand the habits of female tamarin monkeys — creatures who in fact frequently kill their babies. From what researchers have gathered, tamarin mommies have their reasons for killing off some babies while raising others into adulthood. But what’s most striking about these findings is that they may have something to tell us about postpartum depression (PPD).
Mommy tamarins have a lot to consider when bringing a baby into the world. The gestation is pretty long for monkeys (150 days), and they usually give birth to very large twins, according to TIME. What makes raising and providing for twins easier is when there are plenty of male tamarins around to protect the home and provide enough food. Scientists learned that the amount of males available in the “troop” ultimately had a huge impact on whether tamarin monkeys chose to kills their babes or not:
When there were at least three assisting males in the troop, the researches found, the survival rate for infants was an impressive 75%; when there were two or fewer males, the number fell to 42%. When a mother-to-be was the only gestating female in a group, the baby she gave birth to had an 80% chance of surviving at least three months. When there were two or more pregnancies, that forecast plunged to just 20%.
Scientists involved in the study determined that if there simply aren’t enough resources (or males to provide said resources), mother tamarins will “cut their losses” and kill the baby that has little chance of survival anyway.
Anthropologist Edward Hagen, of the University of California at Santa Barbara, conducted a study 1999 that posited how PPD is an “adaptive strategy” to essentially achieve the same results but through a different means. After studying women who suffered PPD, he determined the following:
… the two things that correlated the most strongly were the health of the infant and the amount of child-care support the mother was getting. “Mothers with PPD mother less,” Hagen wrote in his paper. Their depression informs them “that they have suffered a reproductive cost and that successfully motivates them to reduce that cost.”
According to TIME, the study was controversial as it applied an “unsettling”narrative to the pyschological condition that is not the fault of mothers. The critcism that he endured caused him to abandon the study completely. Yet the findings of tamarin mothers do seem to echo some of his research, at least in theory.