Scientists reveal why male proboscis monkeys have such big noses

"Males often produce loud, long-distance calls filtered through the nasal passage, which can travel up to 7 kilometres (4.3 miles) through the jungles of Borneo where they live. Researchers from the University of Osaka carried out CT scans on preserved proboscis monkey specimens, which allowed them to create detailed 3D digital models of their nasal passages. Using computer simulation, they were able to work out that the larger the nose, the lower the frequency of the calls they make."

"This acoustic signal could indicate a male is bigger and is sexually mature, they said - important details for potential mates to know. 'This research, a unique collaboration between a zoo dedicated to rare species conservation, primatologists, and engineers, yielded unexpected results,' Professor Takeshi Nishimura, one of the study's authors, said. 'We are delighted to have uncovered findings that link physical characteristics to vocal communication and social evolution.'"

Proboscis monkeys possess elongated fleshy noses that are especially prominent in males. The bulbous nose acts as a social-status and sexual-quality badge while also shaping vocal signalling. Males emit loud long-distance calls filtered through the nasal passage that can travel up to 7 kilometres through Borneo jungles. CT scans of preserved specimens produced 3D nasal models and computer simulations demonstrating that larger noses generate lower-frequency calls. Lower frequencies can indicate larger body size and sexual maturity and permit individual identification, allowing females and rival males to locate and monitor dominant males and competitors.

Read at Mail Online