Those men catcalling and driving Hummers and hollering at football games and, heck, mansplaining – are they compensating for something else?

Science suggests yes.

A new study finds that monkeys with louder calls also have, ahem, smaller balls – and by extension, less sperm for reproduction.

"In evolutionary terms, all males strive to have as many offspring as they can, but when it comes to reproduction you can't have everything," said lead researcher Jacob Dunn of the University of Cambridge's Division of Biological Anthropology, crushing the hopes of high school boys everywhere.



"When males invest in large bodies, bright colors, or weaponry such as horns or long canines, they are unable to also invest in reproductive traits," Dunn added.

It's unclear whether the results extend to gold chains and Camaros, but this is the first study to find an apparent tradeoff between "vocal investment and sperm production," he said.

The researchers studied Howler monkeys, the That-Guy-from-the-Bleacher-Section of the animal kingdom. Weighing just 15 pounds – or the size of a small dog – the species ranks as one of the loudest on the planet, unleashing a roar that can be heard 3 miles away, powered by vocal cords three times longer than a human's.

Males, true to type, simply yell until a female shows up.



For those living in groups with other males, they tend to have smaller vocal organs but bigger testes, suggesting a "battle for reproduction geared more toward 'sperm competition,'" a statement on the findings described. For male howling monkeys living on their own among women in an – actual quote – "harem" social model, the opposite tended to be true.

"It may be that investment in developing a large vocal organ and roaring is so costly that there is simply not enough energy left to invest in testes," Dunn said. "Alternatively, using a large vocal organ for roaring may be so effective at deterring rival males that there is no need to invest in large testes."