Whether humans, elephants, baboons or fish, adversity experienced early in life often has a negative impact on longevity and health in adulthood. However, this trend is seen throughout the animal kingdom, and there seems to be at least one exception. It’s a mountain gorilla. As long as young gorillas who have experienced adversity are over the age of six, they will live as long as their untraumatized peers, researchers reported May 15. biology today.
“For reasons we’re still figuring out, gorillas seem to be remarkably resilient to childhood adversity,” says University of Michigan biological anthropologist Stacey Rosenbaum, lead author of the new paper. Understanding how one of our closest relatives coped with childhood trauma will help us understand why some can cope in the same way, and how others deal with childhood trauma throughout their lives. She added that it could enhance insight into why people continue to be haunted by negative experiences.
It is difficult to study how long-lived animals in the wild respond to childhood adversity, and so far researchers have had little insight into the impact of such events on non-human great apes. I didn’t. Evidence suggests that chimpanzees and bonobos who suffer childhood trauma in captivity often develop long-term psychological problems. However, it is difficult to reconcile these observations with the fact that these animals are housed in unnatural environments.
The new research was made possible by the existence of a proprietary database currently maintained by the Diane Master Gorilla Foundation, a non-profit conservation organization in Rwanda. Established in 1967, the database contains daily observations over the life of more than 400 of his mountain gorillas monitored in Rwanda’s Volcanoes National Park. “It’s really, really rare to have such detailed demographic data to do a study like this, especially in wild apes,” says Rosenbaum. “Literally hundreds of people went out to see the gorillas every day for 55 years.”
Rosenbaum and her colleagues focused on 253 gorillas from 19 social groups. The researchers found that by the time each animal was 6 years old, they experienced six different types of juveniles, including losing a mother or father, living in group instability, and witnessing the infanticide of fellow young animals. We asked whether they had experienced period adversity. The researchers then looked at the lifespan of each of the animals studied.
Researchers found that young gorillas exposed to multiple adversities were up to 30 times more likely to die by age 6. Surprisingly, however, individuals who survived beyond the age of 6 had no adverse effects on lifespan. In fact, men who experienced the highest levels of adversity tended to live longer than those who experienced the least adversity, a finding that Rosenbaum and her colleagues may attribute to viability selection. I think it’s expensive. “The basic idea is that only particularly high-quality animals can survive the early stages,” she says.
For female gorillas, there was no difference in lifespan regardless of whether they experienced harsh conditions in their first few years. Combined with the findings on male gorillas, this suggests that gorilla species are generally “more resilient,” says Rosenbaum.
“It’s pretty amazing to know that someone who overcomes adversity early on doesn’t affect their long-term survival,” says evolutionary anthropologist Melissa Emery Thompson of the University of New Mexico. He did not participate in the current study. . “Clearly, humans are not gorillas, but comparative data on this phenomenon in long-lived species that share many biological similarities with humans are invaluable.”
Rosenbaum and her colleagues have no definitive explanation for their findings, but they do have a hypothesis. For example, the gorilla whose life is recorded in the database “lives in this strange little bubble” without facing ecological scarcity, says Rosenbaum. Their physical needs are met because water and food are plentiful and forests are protected from loggers and poachers. Animals also live in highly supported and tightly knit social groups. For example, if a young gorilla becomes orphaned, other members of the group, especially alpha males, step in to provide more care.
If this two-pronged explanation turns out to be accurate, it means that social animals need both social support and resources to avoid the harmful effects of early trauma, says Rosen. says Baum. “Gorillas have both,” she added.
Many questions remain, including whether childhood adversity affects gorilla health and what biological mechanisms underpin resilience in great apes. Rosenbaum and her colleagues used the same database to study traumatic gorillas and trauma, measured through hormone levels obtained from fecal samples, disease and injury records, and relationship dynamics. We are already working on a follow-up study investigating differences in gorilla health that are not in the same population.
Despite the vast differences between humans and our closest relatives, the great apes, “we have an enormous amount in common,” Rosenbaum stresses. She suspects that the nature of the gorilla discovery probably applies to humans and other long-lived mammals. “When thinking about how to help children bounce back from early adversity, it’s very important to keep in mind that providing social and financial support alone is not enough,” she said. say. “I don’t think the intervention is very likely to be successful if either is ignored.”
