The first census conducted in Kahuzi-Biega National Park we have knowledge of is the 1979 survey. This counted 223 gorillas, divided into 14 families and 5 solitary males. Another survey was conducted in 1990 and counted 258 gorillas divided into 25 groups and 9 solitary males. The population was showing a slight increase in the individual gorillas.
In 2004 a census carried out revealed 168 low-land gorillas and this was a slight decrease because of the unending war conflicts with in the country during the Ninetieth. However, due to the increased conservation efforts encouraged by the Wildlife Conservation Society and the Institut Congolais pour la Conservation de la Nature (ICCN) in Kahuzi-Biega National Park in the Democratic Republic of the Congo, the 2010 census showed an increase with the number of gorillas at 181 individuals.
Human disturbance within the bridge zone between highland and lowland forests usually prevents gorillas from making contact with their neighbors and this reduces the possibility of out breeding within the Park and hence a constant population.
