Key Facts 13.3-million–13.6 million-year-old fossils from an extinct relative of the howler monkey show signs of being the first leaf-eating ...

Venezuelan Red Howler (Alouatta seniculus). They inhabit rainforests and mountain forests of Central and South America. The loudest monkey. Morning roar of a red howler. Close-up.© ...

Observations of Coiba’s tool-using immature capuchin monkeys show them carrying abducted infant howler monkeys. What is the reason for this behavior? Vanessa Crooks Caught in the act! Capuchin monkeys ...

The “big truck, small man” phenomenon is also seen in the animal kingdom. The loudest howler monkeys were found to have the smallest packages. Hyoid bone size, which is responsible for vocalizations, ...