Perhaps more importantly they bridge the darker half of their existence during which they are not adapted to their environment. And they also satisfy the physical need of their great bodies for recreation in a horizontal position. Animals shot by hunters use their last energies to build their last nest which keeps them from falling. The nest is the last place of refuge. The nest of mother and child physically reproduces the development of the mother and child relation.
Apes spend about two to three years in the nest of their mother.
During this time the child gradually learns to build a nest. The long close contact to the mother's bodily warmth contributes to a sense of safety in the nest. The durability of the nest artifacts is remarkably longer than the factual use, which in general is only one night. Nests left behind by the animals last two months on average. Unfortunately their semantic function in the system of the apes' orientation has not yet been studied.