Aye-ayes build and use many nests—during one study, 8 aye-ayes were recorded to build and use as many as a hundred different nests over a period of 2 years. In lorisoids Lesser bushbaby mothers initially shelter their offspring, usually twins, in a nest or tree hollow, later concealing the infants in foliage while they forage at night. In some species, such as dwarf galagos, the day-sleeping nests may be shared by groups of females or occasionally by visiting males. In hominid apes Hominid apes construct nests during the day or by night, primarily for resting. The nests are not built using instinct but through behavioural patterns which are learned by the young from their parents or clan. Nest building is habitual behaviour, and nest-counts and faecal analysis at each nest site can be used to estimate hominid ape population counts and composition. In the case of orangutans and chimpanzees, social influences are probably essential for the animals to develop successful nesting-behaviour. The nest building behavior is estimated to have originated during the Miocene, when the body of the ancestors of modern apes increased in size. Eventually they became so big that it was no longer possible for them to get both safe and proper sleep on bare branches alone, so they started building sleeping platforms in the trees. This appeared to have happened when their weight passed 30 kilos, as only apes above 32 kilos build nests. Which in turn led to shorter and deeper sleep. In gorillas Gorillas construct nests for day and night use. Day nests tend to be simple aggregations of branches and leaves on the ground, while night nests are more elaborate constructions usually on the ground but sometimes on trees, especially those of juveniles and females in areas submitted to a high poaching pressure. The nests may be wide in diameter and are constructed by individuals. Young animals nest with their mother but do not construct nests until three years of age, initially in close proximity to their mother. Gorilla nests are distributed randomly and the tree species used appears to be opportunistic. In chimpanzees Nest-building is seen in chimpanzees who construct arboreal night nests by lacing together branches from one or more trees. They can also build nap nests to rest in the afternoon, these are usually more poorly constructed than the night nests and can be built both on the ground and on