Loud howler monkey may develop smaller testicles .

Scienctist believes that a loud howler monkeys have a small testicle.

Scientist from Cambridge University finished the research and published under the title "Evolutionary Trade-Off between Vocal Tract and Testes Dimensions in Howler Monkeys" in the online journal Current Biology.

Scientist wrote, "As a result of their anatomical modifications, howler monkeys produce exceptionally low-frequency vocalizations for their body size compared with other mammals,". That's why the loud male howler monkeys are more attractive for female howler monkeys.




source: http://technology.inquirer.net/65720/louder-howler-monkeys-have-smaller-testicles-says-study