In a survey across Africa, Eastern gorillas, the largest living primates, were found to have lost more than half their habitat since the early 1990s while habitats Cross River gorillas, chimps and bonobos have suffered considerable losses, scientists said.
"Several studies either on a site or country level indicated already that African ape populations are under enormous pressure and in decline," Hjalmar Kuehl of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who helped organize the research, told the BBC.
"But despite these expectations it is outrageous to see how our closest living relatives and their habitats are disappearing," he said.
In western Africa forest clearance and hunting are destroying habitats while in Central Africa large regions of forest are no longer suitable for great apes because of extensive hunting to supply the trade in bushmeat, researchers said.
"The situation is very dramatic; many of the ape populations we still find today will disappear in the near future," Kuehl said. "In an increasingly crowding world with demand for space, wood, mineral resources and meat, apes will continue to disappear."