In what year did the census begin? Why was it important? Who helped Fossey with the task?

In 1969, Bob Campbell and a Belgian woman named Alyette DeMunck helped Fossey start a comprehensive census. The task began in the area around Karisoke, but the project eventually expanded and was completed annually. One part of the census-taking process was to count nights. The job was often tedious but necessary, because it might have been the only way to discover infants because their mothers carry them so close to their bellies.