You’ve heard the saying: Size matters.
Of course, it depends on what you’re talking about — and whom you’re talking to.
But for male proboscis monkeys from Malaysia, it turns out that having a bigger certain appendage makes them more likely to attract a mate from the opposite sex, according to a study published in the journal Science Advances.
More specifically, we’re talking about the monkeys’ recognizable noses.
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The study was conducted at the Lower Kinabatangan Wildlife Sanctuary in Sabah, Malaysia, where scientists examined how the monkeys behaved, measured their different body parts and recorded their vocalizations.
Researchers found that along with having more mates, male monkeys with bigger noses were more likely to be the dominant primate in their group, Newsweek reported.
For a long time, the evolutionary purpose of the big noses was unknown, Sen Nathan, a scientist in the Sabah Wildlife Department and a Ph.D. student at the Danau Girang Field Centre, said in a statement.
“Although the unique nature of the ‘odd-nosed’ proboscis monkey has long been admired as an extremely attractive visual feature by biologists,” Newsweek reported the statement as saying, “explanations for its evolution have so far been gleaned more from folklore than from science.”
But now the study offers some reasons for the monkeys’ big sniffer.
The enlarged snout can “serve as advertisements to females in mate selection,” researchers wrote.
That means a big nose can give a female proboscis monkey a hint about the rest of a prospective mate’s body and the role he would play in the larger community.
“We also found that males with larger noses also tended to have larger body mass and testis,” Ikki Matsuda from Chubu University and Kyoto University in Japan told The Star. “This suggests that nose enlargement is a reliable predictor of social dominance and high sperm count.”
And since female proboscis monkeys seem to prefer mating with a male who packs a bigger nose, they are more likely to pass down the gene for a large snout and keep the trait alive, the study suggests.
Those findings help shed more light on the monkeys, which have protected status in Sabah, said Benoit Goossens, director of the Danau Girang Field Centre.
“Every piece of information that allows us to better understand the behaviour of these charismatic animals is important,” he told The Herald. “Now our tour guides will be able to tell their guests that size matters, and that males with larger noses attract more females in their harem.”