University of Georgia

Primatologist helps bring beasts to life

baby gorilla held by mother

Most moviegoers watching “War for the Planet of the Apes” this summer had no idea that the gorillas sounded authentic because of guidance provided by UGA primatologist Roberta Salmi, who has done extensive research on the vocal communication of western gorillas.

For her Ph.D. dissertation, Salmi spent 18 months in the forest of the Republic of the Congo and collected more than 2,000 recordings of gorillas’ vocalizations.

Gorillas live in small groups, typically one male and a few females with infants. In these relatively cohesive units they “chat” with each other frequently—exchanging eight calls per hour on average, according to Salmi.

“Most of their calls are exchanged during non-aggressive contexts, and comprise soft grunts and grumbles,” she said. “They laugh when playing, they hum when feeding, infants whine and cry, and they call each other when separated.”

Recordings of gorilla sounds are extremely rare, so Salmi’s expertise is in high demand. She provided 40 calls for the 2014 film “Dawn of the Planet of the Apes” and another 40 new calls when the filmmakers got in touch for assistance with this year’s film.

“They wanted help on gorilla behavior, vocal production, individual distinctiveness, effects of age on sounds, postural position during vocalizations,” said Salmi, assistant professor in the Franklin College of Arts and Sciences. “I also gave them some comments on the sounds made by the actors so that they better resemble gorilla vocalizations.”

This brief appeared in the fall 2017 issue of Research Magazine. The original press is available at