Since before the orangutan branched about 12 million years ago, all the great ape species had a vocabulary—signals, gestures, grunts, and screams—in various contexts, potentially ranging into the thousands. These early apes communicated with not only a wide variety of sounds and gestures but also different levels or gradations of these signals. For instance, one type of scream might indicate danger from above, while another might signal danger on the ground. Depending on the situation, the scream could represent danger at a distance, an immediate personal threat, approaching danger, or imminent danger. Similarly, the same sound could have variations to signal that an attack is in progress or that one just occurred.

Imagined Image: Found in Europe, Rudapithecus hungaricus likely lived from about 12 to 10 million years ago but was not likely our direct-line ancestor. It likely had a vocabulary similar to orangutans today, ranging into the thousands of gestures, grunts, and screams in various contexts