Spanning 100 acres in Balboa Park, the San Diego Zoo is not only one of the largest ... including hippos and bonobos in the Lost Forest, polar bears in the Northern Frontier, rhinos in the Urban ...

For the study, the researchers analysed 75 hours of video footage involving nine bonobos, four orangutans, and four gorillas at San Diego Zoo in California, US, and a group of 17 chimpanzees at ...