Read the following dialog and answer the questions.

Galih : Look! There are many monkeys on this hill.
Aji   : Yes. They live on the tree and like clinging onto tree branches and leaping from one tree to another. 
Galih : How can they cling onto branches?
Aji   : They can use their tails or leg to cling onto tree branches.
Galih : Oh I see. What about their diets? Are they herbivorous?
Aji   : No,they are not. Although their diets are identical with nuts, they are omnivorous. They eat seeds, flowers, eggs, fruits, leaves, and small insects including spiders.
Galih : Anyway, can I feed them some nuts?
Aji   : Yes, you can but you must be careful because some of them are very sociable and a bit naughty.

Why are monkeys omnivorous?