Researchers from the Bronx Zoo-based WCS, working in close cooperation with the Republic of Congo government, combed rainforests and isolated swamps in two adjacent areas covering 47,000 square kilometers, counting the "nests" that gorillas build from leaves and branches each night for sleeping. "These figures show that the northern Republic of Congo contains the mother lode of gorillas," said WCS president Steven Sanderson. The population density in one particularly rich forest patch was estimated at eight individuals per square kilometer.
WCS scientists say that the high numbers of gorillas in the region are due to successful long-term conservation management of the Republic of Congo's protected areas along with the remoteness and inaccessibility of key locations and food-rich swamp and open-canopy forest habitat. While many of the gorillas were found outside reserves, the government is committed to creating a new national park in the region, WCS notes. Gorillas across Central Africa are threated by commercial bushmeat hunting and the spread of the Ebola virus, fatal to apes as well as humans.