Is adopting a child a benevolent or a foolish act? If you were taking a cold evolutionary perspective, it would appear to be the latter. So why do many animals, including elephant seals and humans, do it all the time?
Children who don't know better might throw spitballs or pull hair to get another child's attention, and it turns out that certain monkeys do something similar. Female capuchin monkeys have been observed throwing rocks at males as a form of courtship.
Self-awareness, the ability to assess and even doubt one's own thoughts, is a crucial sign of intelligence, but it's also one of the hardest traits to identify. Macaques have now demonstrated they have self-awareness...which might explain our own evolutionary story.