As best I have been able to determine from reading literature, chimpanzees, gorillas, bonobos, and orangutans have been largely confined to tropical and subtropical forests, at least during the Holocene. Why? Why haven't they adapted to more temperate habitats? Why haven't they diversified as much as monkeys have, for example?
The apparent difficulty apes have swimming could have minimized their movements in some areas (e.g., separating bonobos and chimps in Africa) or different subspecies of orangutan on Borneo and Sumatra) during relatively moist periods; but during drier periods they presumably spread out more broadly, for instance into Europe. But why didn't they thrive in Europe? Why did only humans (Homo erectus etc.) (and yeti?) thrive in temperate and ultimately boreal habitats?
During the Miocene, when warming climate eliminated such forests in much of Africa, and such forests developed in Europe at least as far north as the Alps, followed later by cooling and redevelopment of such forests in Africa, apes occupied those forests. But did they also adapt to any other habitats such as savannas or grasslands? I've read speculation that they ate bark, seeds, and a few other grassland plants, which might have included berries. Any indication that they dug up roots, bulbs, corms or tubers, or hunted rodents?
Thanks
Steve Stringham (bear biologist)