A 2005 study observed this behavior in macaques; male monkeys would pay some amount of fruit juice to look at leaders' faces or females' hindquarters ("socially

A 2005 study observed this behavior in macaques; male monkeys would pay some amount of fruit juice to look at leaders' faces or females' hindquarters ("socially useful information"). https://www.nature.com/news/2005/050131/full/news050131-5.html https://www.nature.com/news/2005/050131/full/news050131-5.ht...