Proboscis Monkeys

I did my tables project on Proboscis Monkeys. They are very strange animials. Their noses are massive. I am interested in how their noses get so large. I looked it up and it is seen that the big nose is thought to be used to attract females and is a characteristic of the males, reaching up to 7 inches in length. The females also have big noses compared to other monkey species, but not as big as the males. Besides attracting mates, the nose serves as a resonating chamber, amplifying their warning calls. When the animal becomes agitated its nose swells with blood, making warning calls louder and more intense.I just can't beleive how big their noses are!