Overview

• Monkeys' vocal membranes allow for frequency jumps up to five times larger than those possible in human voices.
• These membranes, which humans lost during evolution, destabilize voice pitch but enable a wider vocal range.
• New World monkeys, such as howler and spider monkeys, can produce vocalizations exceeding three musical octaves.
• An international team used fieldwork, CT scans, and simulations to study monkey calls in a Bolivian wildlife sanctuary.
• The findings highlight evolutionary trade-offs in vocal anatomy and open avenues for exploring primate communication and social behavior.