Deep Monkey Roars
We can all shout loud in fun or in fear, but some of us monkeys can shout louder than others. The article below talks about the Howler monkeys and the howling noises they make. It says an individual roar can be heard 5km away-wow!!
Howler monkeys make among the loudest, deepest sounds of any land animal, and males use their roars to attract the ladies for mating and intimidate other males.But scientists on Thursday said they have discovered a curious paradox: males that make the lowest-frequency calls considered the most alluring to potential mates are endowed with the lowest reproductive potential.
The research focused on a cup-shaped bone, the hyoid, located above the larynx that creates a resonating chamber to amplify vocalizations.Among nine howler monkey species studied, those with the biggest hyoid produced the deepest and lowest-frequency calls, but also had the littlest testes for sperm production.”We discovered that the largest hyoid bones were found in howler monkey species with the smallest testes volume, and vice versa,” University of Utah anthropologist Leslie Knapp said.University of Cambridge biological anthropologist Jacob Dunn called it an “evolutionary trade-off” for male howler monkeys between vocal tract and testes size.”This means that different species of howler monkeys either invest in one of these traits or the other, but not both,” Dunn said. “I think the main message is that when it comes to reproduction, you can’t have everything.
“Howler monkeys, found from southern Mexico to Argentina, spend most of their time in tall trees with the help of their gripping, prehensile tails, munching leaves, fruits and flowers. Their howls can be heard 3 miles (5 km) away.”Howls sound a bit like the roar of a lion, but many howlers produce even deeper and more complex sound,” Knapp said. “Deeper howls suggest large body size, so howlers with deep howls give the impression that they are bigger than they really are. This is an advantage for males that are competing to mate with females.”