Adolescent male chimps still need their mamas

FEBRUARY 18, 2020

by Robin A. Smith, Duke University

Even kids who are nearly grown still need a parental figure to help them navigate the long path to adulthood—and our closest animal relatives are no exception.

A new study of wild chimpanzees finds that males whose moms were present during their tween and teen years had higher odds of survival later in life, compared with their peers who lost their mothers before they finished puberty.

The results appear in the February 2020 issue of the journal Behavioral Ecology and Sociobiology.

Beginning in the 1960s, researchers led by primatologist Jane Goodall started monitoring the wild chimpanzees living in Gombe National Park in western Tanzania, making note of things like births, deaths, who was related to who and how the animals interacted. Using more than 50 years of data for 247 chimpanzees, a team from Franklin & Marshall College, The George Washington University and Duke University examined the impacts of having or losing a mother at different stages of a chimpanzee's growing up.

Perhaps not surprisingly, they found that a mom's continued presence after weaning means better outcomes for her kids. Chimpanzees whose mothers were still around by their tenth birthdays lived longer than their orphaned peers.

But at later stages of growing up, the effect was stronger for sons than daughters. Sons whose mothers were still around between the ages of 10 and 15 were more likely to survive than sons who lost their mothers during that time, whereas daughters did just fine either way.

There's a good reason for mom's diminishing influence on daughters, the researchers say. In Gombe National Park, half of all chimpanzee females leave their birth families behind at puberty. But adolescent males stay put, which means mothers and sons are more likely to form lifelong bonds.

Exactly how a mom's continued presence enhances her adolescent offspring's survival is still unclear, the researchers say.

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