Study: Early adversity sees most species suffer later on but not gorillas

Most species, including humans, who experience early life adversity suffer as adults, but gorillas break the mould, new research suggests.

Previous studies by the Dian Fossey Gorilla Fund revealed that young gorillas are resilient to losing their mothers, in contrast to what has been found in many other species. However, losing their mother is only one of many bad things that can potentially happen to young animals, researchers say.

Senior author Stacy Rosenbaum, a University of Michigan anthropologist, said: “Assuming that you survive something that we consider early life adversity, it’s often still the case that you will be less healthy or you will have fewer kids or your lifespan will be shorter – no matter what species you are.”

Instead, the researchers found that gorillas who survived past the age of six were largely unaffected by difficulties they encountered as infants or juveniles.

In humans, it is difficult to establish whether we, for example, develop cancer or die early as adults because of an adverse event – such as the death of a parent or sibling – early in life, or whether it is because of a multitude of behavioural, environmental and cultural factors or a combination of all of the above.

Researchers suggest studying these early adverse events in nonhuman species could help them understand how such events affect humans, and how to mitigate them.

According to the study, the findings that gorillas show a different pattern suggests early life adversities can be overcome.

Understanding why and how this happens can have significant implications for humans, the researchers suggest.

The study looked at 55 years of long-term data collected in 253 wild mountain gorillas.

These animals live in Volcanoes National Park in Rwanda, and have been monitored for more than five decades by the Dian Fossey Gorilla Fund.

Researchers identified six different kinds of early life adversity – losing a father or mother, experiencing the death of a group member by infanticide, social group instability, having few age-mates in the social group, and having a competing sibling who was born soon after them.

The researchers looked at what happened when a gorilla experienced none, one, two or three or more adverse events.

They found that the more of these adverse events gorillas experienced before the age of six, the more likely they were to die as juveniles.

However, if they experienced early adversity, but survived until age six, there was no evidence their lifespans were shorter, no matter how many adverse events they suffered.

According to the study, if a gorilla experienced three or more forms of adversity, it actually lived longer.

Researchers found gorillas show a different pattern.