This human nature keynote by Laurie Santos places her thoughts on the biggest difference between an animal's mind and a human's. She believes this answer is a large question that would possess different opinions, but she offers her unique take.
Laurie believes that unlike animals, humans interact with each other with a motivation to share. They like to show cool things to each other and this can be proven by the popularity of social media networks. Humans want to show off neat and interesting things. This can be perceived as a major difference between how humans bond with each other.
Monkeys seem to lack that motivation of sharing which is a fundamental process in cooperation and team building. This is largely due to the lack of communication they possess.