Monkeys were known as the under evolved to some human researchers who worshipped Charles Darwin, and didn't think religion was actually a thing, while at the same time thinking it would be scientific. If evolution was real for butterflies, and frogs, then why haven't you seen the evolution of a human up close.
Of course being a zoo, there were a ton of different breeds of these monkeys, which were spider-monkeys, chimpanzees, gorillas, orangutans, and lemurs. You were given a pamphlet about what kind of fruits these kinds of animals would be able to eat, and knowing that monkeys were able to eat any kind of fruit they could get their hands on. The difference between primates, and other animals was that primates were the only animals with opposable thumbs that could help them grab food.