JAKARTA (AP).- When British naturalist Alfred Russel Wallace arrived in Borneo’s jungles 150 years ago, one of his great hopes was to see orangutans. Even he was surprised at his success, spotting the red apes feeding along river banks, swinging between branches, and staring down from trees almost the moment he arrived. He saw 29 — shooting more than half of them and sending their skins and skeletons back home — in just 100 days, an experience shared by many other adventurers and collectors during the same period. “Whereas some early explorers would see as many as eight orangutans in one tree or encounter 35 along a river in one day, spotting even one in the wild in the same undisturbed forests is now rare,” said Erik Meijaard, one of the authors of a study published Wednesday in PLoS One, a journal of the Public Library of Science. “This prompted us to ask if these notoriously solitary apes once lived in much higher densities,” said Meijaard. “We believe hunting may h