The proboscis monkey has a large nose for a number of reasons. First, it helps amplify the sounds they use to communicate with each other, which can sometimes be heard from half a mile away! Additionally, the large noses of Proboscis Monkeys help males attract mates, as males with larger noses are considered more attractive.
Finally, the large noses of the Proboscis Monkeys act as a cooling system, helping them stay hydrated in hot climates. In conclusion, the Proboscis Monkeys have large noses for communication, mating purposes, and to help them stay cool and hydrated.