2015年10月26日 · Howler monkeys produce a bass pitch comparable to animals of much larger body sizes, such as red deer and elephants, and in general, larger vocal chambers can produce deeper sounds. Much of the...

2015年10月22日 · Do males with bigger testicles have deeper voices? The jury is still out on humans, but if you're a howler monkey, forget about it. A new study finds that the animals can make a lot of noise or a lot of sperm—but trying to do both just takes too much energy.

2016年2月24日 · This schematic of a howler monkey’s vocal tract shows the cup-shaped hyoid bone of an adult male Bolivian red howler monkey (Alouatta sara). Howler monkeys produce powerful roars, which may function to ward off males from other groups.

2015年10月22日 · Male howler monkeys are famed for their deep, powerful roars, which are among the loudest noises made by terrestrial animals, and may help them compete with other males. But, alas, species...

The black howler (Alouatta caraya) or black-and-gold howler, [2] is among the largest New World monkeys and a member of the Alouatta genus. [3][4] The black howler is distributed in areas of South America such as Paraguay, southern Brazil, eastern Bolivia, northern Argentina, and Uruguay. [5][6] This species is sexually dimorphic, with adult mal...

CAMBRIDGE, England, Oct. 22 (UPI) -- Howler monkeys can't have it all. Evolution offers a choice: big balls or big calls. The choice dictates not only physical attributes, but a style of...

2015年10月23日 · New analysis from the University of Cambridge finds that for howler monkeys, louder calls equal smaller balls. The howler monkey is a curious creature, a terrier-sized primate with a...

2015年11月13日 · Among howler monkey species, loud calls come at the expense of testicle size and sperm production—or to put it another way, monkeys with the largest testes don't make as much noise

2015年10月22日 · A male howler monkey living in a harem community by himself may have evolved to warn off other suitors with deeper calls. At the same time, his balls shrank, since there is less competition.

2015年10月22日 · In a new study, published in Current Biology, we were interested in examining this evolutionary trade–off in howler monkeys. These monkeys, of which there are ten species distributed from...