Gorillas need restful sleep to stay healthy. At dusk, they take the time to create a safe and comfortable place to rest: the nest. It can be on the ground or in the trees, depending on the gorilla's age and the type of habitat. Mountain gorillas gather leaves, twigs, and soft grasses to form a cozy structure that provides comfort and protection during the night. They prefer to build a new one each night to avoid parasites and bacteria that can accumulate in old nests.