Why are apes and monkeys alike?

A Baboon is a monkey. Baboons are classified as an Old World Monkey. So pretty much the answer to you question is they are similar in basically everything, because they are monkeys. The only difference is the physical look, i.e. the world famous Baboon butt and others. The answer to you question also varies widely based on what sub-species of Baboon you are trying to compare and to what other monkey species you are comparing it to.