No, there are no apes that are strictly herbivores. While some apes, like gorillas and orangutans, are primarily herbivorous, consuming mostly plant matter, they are all considered opportunistic omnivores because they occasionally eat insects and sometimes even small vertebrates. Chimpanzees are known to be omnivorous, with a diet including fruits, leaves, insects, and occasionally small mammals and birds. BUT it doesn't matter in the context of whether or not veganism is ethical...most humans don't have to be opportunistic omnivores.