There has been a startling increase in the estimated world population of western lowland gorillas, a critically endangered species. A new census by the Wildlife Conservation Society has found more than 125,000 of the secretive great apes in the northern part of the Republic of Congo. To put that figure in perspective, the entire population of western lowland gorillas across seven Central African countries was estimated at fewer than 100,000 animals in the 1980s, and conservationists believed that number had been halved because of hunting and disease. Western lowland gorilla. (Photographs by Thomas Breuer/Wildlife Conservation Society-Max Planck Institute for Evolutionary Anthropology) 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...