Primates possess special anatomical structures in their throats called vocal membranes, allowing for yodeling at higher ...

including the black and gold howler monkey (Alouatta caraya), tufted capuchin (Sapajus apella), black-capped squirrel monkey ...

including the black and gold howler monkey (Alouatta caraya), tufted capuchin (Sapajus apella), black-capped squirrel monkey (Saimiri boliviensis), and Peruvian spider monkey (Ateles chamek).

Primates studied included the black and gold howler monkey, tufted capuchin, black-capped squirrel monkey, and Peruvian spider monkey. Monkeys, scientists found, had a secret yodelling weapon ...