The red howler species is the most common, but it is often targeted by hunters eager for bushmeat. Other species of howler monkey may be critically endangered over sections of their ranges.

This photo is of a skull, mandible and hyoid bone of a red howler monkey, showing the enormous size of the hyoid relative to body size.

This is a computer generated 3-D model of a Bolivian red howler (Alouatta sara), with the hyoid bone in red. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases ...