Orphaned chimps develop less muscle mass than their peers with living moms

Jan. 7 (UPI) — The benefits of the nurturing presence of a mom, beyond simply a source of food, are well documented among humans. Time spent with mom is associated with cognitive, social and emotional development.

The benefits moms offer juvenile chimpanzees, after they’ve weaned, are less well understood, but a new study, published this week in the journal Frontiers in Zoology, suggests orphaned chimps develop less muscle mass than chimps with living mothers.

“We assessed the muscle mass of 70 offspring from 41 mothers by means of urinary creatinine concentrations, a by-product of metabolic activity in muscles,” Tobias Deschner, a researcher at the Max Planck Institute for Evolutionary Anthropology in Germany, said in a news release.

The analysis showed, unsurprisingly, that muscle mass increased as juveniles got older, but scientists also found a difference in the muscle mass of chimpanzees still spending time with their moms and those who were deprived of their mothers shortly after weaning.

Researchers also determined that chimpanzees with moms of high social status tended to have greater amounts of muscle mass.

The findings prove that even after offspring are nutritionally independent, mothers continue to exert a positive influence on their lives.

“Our results emphasize the crucial role of mothers and suggest that even in the absence of consistent direct provisioning from mothers to offspring, chimpanzee mothers still indirectly influence food consumption in their offspring,” said MPI primatologist Liran Samuni.

Authors of the new study suggest chimpanzee moms likely provide types of support similar to the assistance offered by human moms.

“Mothers may provide support to their offspring during competitive interactions with others, and increase their chance to ‘win’ conflicts, or soften reactions of offspring to challenging situations,” researcher Patrick Tkaczynski said. “Also, mothers may provide opportunities for offspring to learn how to find and access hard to extract or rare food items.”

Previous studies have shown chimpanzees learning tool use and feeding techniques by watching and copying their parents and peers.

And don’t worry dads, research suggests male companionship is valued, too. One previous study showed that when dad takes on parenting duties, mammals evolve bigger brains.

No species puts more time and energy into parenting than humans do, but the latest research suggests the deep companionship between parent and child has deep evolutionary roots.


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