This is what research published in Scientific Reports says. Scientists from the ANU (Australian National University) explained its usefulness. The nose of the ugliest monkeys in the world, the proboscis monkeys, is a weapon of seduction.
Attracting females is the main purpose that male proboscis monkeys achieve by displaying their large, long, drooping noses. Endemic to the island of Borneo, they are described as one of the ugliest animals in the world. The lead author is Dr. Katharine Balolia. They scanned proboscis monkey skulls to take measurements of the primates’ bony nasal cavity. They found that it evolved to allow them to make louder, deeper calls.
Exercising dominance
“We wanted to understand why the noses of male proboscis monkeys are so big,” Balolia said. “They are much larger than the females, and have a different shape.”
“Being able to make louder, deeper calls helps male monkeys assert their health and dominance. This helps male monkeys attract females and scare away other males. The more females a male can attract, the more it allows him to father more offspring. “A big nose shows quality and status to potential female partners.”
The jungle environment could explain why their noses evolved to become so large. «Proboscis monkeys live in coastal mangroves and forested environments. They often cannot see each other through the trees. “That’s why strong nasal calls are important for communication.”
attractive ornament
The fleshy tissue of the nose probably grew larger over time. It improved its ability to emit nasal squawks and roars. Proboscis monkeys stiffly straighten their noses when making these calls. Females find large noses visually attractive for selecting mates. It is an honest sign of health and dominance. The noses of the ugliest monkeys in the world make them desirable specimens.
The bony opening of the nasal cavity of male proboscis monkeys becomes larger with age. It is consistent with older males having larger noses. “This coincides with the moment when they reach a state of dominance among other male monkeys. It allows them to scare away other males and attract many females that are ready to reproduce,” Balolia said.
