There could be any number of incentives, i.e. health benefits. Apes, just like birds, builds nests and this &quot;ritualistic&quot; behaviour could be seen as an extension of cleaning.<p>Being this calculated about this seemingly arduous task obviously hints at something more advanced than cleaning (i.e. spiritual reasons), I&#x27;m just trying to bridge the gap between &quot;calculated rituals&quot; and &quot;random rituals&quot;.