Research
In the second half of the 1980s and the early 1990s, many research topics focused on intraspecific variation. Not only were behavioral ecologists as a whole recognizing the importance of intraspecific variation, but the Karisoke study groups were exhibiting variation in their composition. In general, the groups became larger, and included more related females and more adult males.

This variation in group composition challenged some of the long-held notions about gorilla social behavior. It became clear, for example, that under certain circumstances, nepotism among females could influence the nature of their social relationships. While these findings did not undermine the fundamental concept that male-female bonds are the bases of group cohesion, they have enabled us to draw a more complex picture of gorilla sociality. In addition, the long-term existence of groups with more than one silverback has led to a better understanding of within-group male-male competition and brought the one-male mating system of gorillas into question. These multimale groups have also allowed us to document behaviors rarely, or never, observed in one-male groups, namely herding of females during inter-group encounters and interpositioning by females and infants to diffuse tension during male-male conflicts. These large groups finally meant that several females within a group could have offspring over a short time-span, which opened the way to more detailed investigation and comparison of immature development.

Researchers also recognized that the current knowledge of gorilla feeding ecology was based on a small subset of their habitat. This led to a study encompassing a larger proportion of the Virungas. Studies on non-gorilla features of the ecosystem were also initiated, for example, the feeding ecology of large ungulates such as bushbucks, buffaloes and elephants.

At the same period, new non-invasive technologies enabled researchers to examine underlying physiological mechanisms of behavior with hormone assays. Genetic studies were also initiated, to address questions of taxonomy, genetic variability, and paternity.

Conservation
It can be said that, at the end of the 1980s, conservation efforts had advanced to the stage where the future of mountain gorillas looked optimistic. The 1989 gorilla census in the Virungas showed a continued increase in population size and growth. Deliberate poaching had become extremely rare. Gorilla-based tourism was thriving in Rwanda and Democratic Republic of Congo (then Zaire) and was being developed in Uganda. Rwanda had a Veterinary Center devoted to monitoring the health of the gorilla population. Conservation education programs were in place in all three countries with mountain gorillas, and the two mountain gorilla sites in Uganda, Bwindi Impenetrable and Mgahinga forests, were on the brink of being made national parks. Unfortunately, this promising situation would not last long.

The early 1990s were a start to a tragic era for the people and the wildlife of the Virunga region. In October 1990, war broke out in Rwanda and as a result, tourism, one of the mainstays to gorilla conservation and to the Rwandan economy, declined drastically. Researchers and conservation personnel coped with land mines, gunfire, and mortar shells near or in the park. To make matters worse, instability on the Congolese side of the Virungas, starting in 1991, was eroding the ability of the park system to manage its gorillas. Conservation organizations had to develop contingency plans for working in times of great uncertainty. The only good news was that in 1991, Uganda made both Bwindi Impenetrable Forest and the Mgahinga Game Reserve national parks, a boost to the fortunes of mountain gorillas. Despite the violence in Rwanda, research and conservation activities at Karisoke continued. In fact, while several students from the Université Nationale du Rwanda conducted short-term studies at Karisoke, data for four long-term research projects were collected.

Fighting in Rwanda escalated during 1993 and in February of that year, the Karisoke Research Center was looted and destroyed. Everyone was evacuated, but after a short period, the Rwandan field staff resumed their work, taking the long daily trek from their homes into the forest every day to monitor the study groups. Thanks largely to the dedication and skill of these men, there was barely a gap in the long-term monitoring of gorillas. Karisoke made a remarkable comeback, concurrent with a reduction of open hostilities in Rwanda. By August of 1993, DFGFI had completely rebuilt and modernized the research center. Research on gorillas continued, along with studies of other features of the ecosystem. But the lull in the violence was misleading.