http://www.cell.com/current-biology/fulltext/S0960-9822(15)01109-4 A new study finds that Howler monkeys scream louder when they have smaller testicles. The study published yesterday in the journal Current Biology said that howler monkeys with deep roars — used to attract females, deter love rivals and scare off predators — tend to also have smaller testicles and a shortage of sperm compared to … Continue reading LOUD VOICES AND SMALL TESTICLES