Now 20, she has become a successful mother, raising three offspring. Ubufatanye experienced the loss of her mother and father and the disintegration of her family group before the age of 5. While viability selection may be part of the story, the patterns in our data strongly suggest that as a species, mountain gorillas are also remarkably resilient to early adversity. Part of this hardiness, especially for males, may be due to a phenomenon called viability selection: Only the strongest animals survive early adversity, and thus they are also the animals with the longest life spans.

In fact, gorillas that experienced three or more forms of adversity actually had better survival outcomes, with a 70% reduction in the risk of death across their adult years. We were surprised to discover, however, that most of the repercussions of these hardships were confined to early life: animals that survived past the age of six did not have the shorter life spans commonly associated with early life adversity in other species. This is a strong indication that these experiences were indeed adverse from the perspective of a gorilla. Many young gorillas didn't survive these challenges. These experiences are the gorilla equivalent of some kinds of adversity that are linked with long-term negative effects in humans and other animals. We used this data to identify six adverse events that gorillas younger than age six can endure: maternal loss, paternal loss, extreme violence, social isolation, social instability and sibling competition. We conducted doctoral and postdoctoral research with the Fossey Fund and have collaborated with other scientists there for more than 20 years.įrom their database, which stretches back to 1967, we extracted information on more than 250 gorillas tracked from the day they were born to the day they died or left the study area. The best data in the world to conduct such a study comes from the Dian Fossey Gorilla Fund, which has been following individual mountain gorillas in Rwanda almost daily for 55 years. Primatologists know that males can survive into their late 30s and females into their mid-40s. This is no mean feat, given gorillas' long life spans. To do this, we needed exceptionally detailed long-term data on wild gorillas across their lifetimes. Researchers analyzed decades of observational data to determine how life turned out for young gorillas that had faced adversity. However, there are interesting hints that things might work differently in mountain gorillas, which are one of humans' closest living relatives.

Given the connection between adverse events while young and poor health later in life, one might expect that Titus' unlucky early years would predict a short, unhealthy adulthood for him. Activities like smoking and unhealthy food choices can't be the whole story, then, since animals don't engage in typical human health risk behaviors.

For example, female baboons who have the hardest childhoods have life spans that are on average only half as long as their peers that have the easiest. Often, these outcomes trace back at least in part to what public health researchers call health risk behaviors-things like smoking, poor eating habits and a sedentary lifestyle.īut researchers have documented the same kinds of problems in adulthood in nonhuman animals that experienced early life adversity. People who experience these kinds of traumas, assuming they survive the initial event, are more likely to suffer health problems and social dysfunction in adulthood and to have shorter life spans. Early life adversity can take a wide variety of forms, including malnutrition, war and abuse. In people, a rough start in life is often associated with significant problems later on. Juvenile Titus, who was at a developmental stage similar to that of an eight- or nine-year-old human, experienced more tragedy in his first four years of life than many animals do in a lifetime. In the chaos that followed, his younger sister was killed by another gorilla, and his mother and older sister fled the group. Poachers killed Titus' father and brother.

Mountain gorilla predators