MAY 28, 2021 10:02 AM PDT

Wild Gorillas Adopt Orphaned Babies

WRITTEN BY: Anne Medina

For a primate infant, the loss of their mother can be a death sentence—from starvation to the threat of violence from unrelated males, there’s a world of danger without mom to guide you. Even if the infant survives, the ramifications of motherlessness can follow orphaned primate such as baboons and chimpanzees well into adulthood, leading to lower social rank and reduced reproductive success.

But a new analysis of over 50 years of data on mountain gorillas at the Karisoke Research Center in Rwanda reveals that orphaned gorillas don’t suffer the same poor outcomes, according to research published in eLife on March 23.

Researchers tracked the development of 59 gorillas orphaned between two and eight years old. Scientists found no differences between the orphans’ survival rate, the females’ age at first birth, and the survival of their first offspring through infancy—a rarity among social primates. The researchers attributed this to a ‘buffer’ effect created by the infants’ other relationships within their troop, particularly with their agemates and dominant males.

This form of alloparenting—parenting by an individual that’s not an infant’s biological parent—is thought to be evolutionarily favored within closely-related social groups. While alloparenting doesn’t provide the same genetic payoff as rearing a direct descendant, it does facilitate the preservation of common genes.

But mountain gorilla males that spend time babysitting infants, even unrelated ones, reap genetic dividends down the road. Previous studies of Rwandan mountain gorillas indicate that pro-social behavior toward infants by males is a predictor of their future reproductive success. It’s possible that female gorillas simply find an attentive father attractive, the authors suggested.  

An unrelated study published recently in Scientific Reports provides more evidence of altruistic behavior in non-human primates. Between 2019 and 2020, two female bonobo chimpanzees in the Democratic Republic of the Congo adopted infants from outside their social groups—and thus, outside their genetic lineage. These are considered the first documented cases of great apes rearing completely unrelated infants.  

About the Author
  • Anne is a science writer based in the Southeastern United States, one of the unsung biodiversity hotspots of the world. She channels her passion for animals and ecology into her work as a science communicator, making the latest discoveries accessible and engaging for the public.
You May Also Like
JAN 23, 2021
Microbiology
Host Vouchering & How Can It Improve Pandemic Response
JAN 23, 2021
Host Vouchering & How Can It Improve Pandemic Response
About a year ago, I wrote about the virus that would come to be known as SARS-CoV-2 for the first time. And while we've ...
FEB 09, 2021
Plants & Animals
Venus Flytraps Generate Magnetic Fields
FEB 09, 2021
Venus Flytraps Generate Magnetic Fields
The Venus flytrap (Dionaea muscipula) might be the most famous carnivorous plant; it can entice prey to land on its leaf ...
MAR 05, 2021
Plants & Animals
Some Exceptional Dogs Can Quickly Learn New Words
MAR 05, 2021
Some Exceptional Dogs Can Quickly Learn New Words
Researchers have determined that exceptional dogs only have to hear a new word four times before they learn it. While mo ...
MAR 17, 2021
Microbiology
Novel Bacteria Discovered on Space Station
MAR 17, 2021
Novel Bacteria Discovered on Space Station
Scientists have known that wherever humans go, we carry microorganisms with us, and the International Space Station is n ...
MAR 22, 2021
Plants & Animals
As Winters Warm, Animals and Plants are on the Move
MAR 22, 2021
As Winters Warm, Animals and Plants are on the Move
While there was a brutal winter storm in the Texas region only a few weeks ago, climate change is causing winters to war ...
MAY 29, 2021
Space & Astronomy
Climate Models Overestimate Role of Greenhouse Gases in Global Warming, Says New Study
MAY 29, 2021
Climate Models Overestimate Role of Greenhouse Gases in Global Warming, Says New Study
Researchers have that there was four times more soot in the pre-industrial Southern Hemisphere's atmosphere than pre ...
Loading Comments...