They were about the same age. And later on, they both erupted a left lower tooth first and then left lower right and then the upper left and the upper right. Same time. Their expressions, their attitudes devolved same time. They started grabbing more with their hands. But when the change came when the orang started grabbing with his feat, Brad never tried to do that. But then the human infant progressed much more rapidly and the orang progressed much more slower and the differences became greater. And if you look at the skeleton of a baby chimp, orang and a human baby, the skull is almost identical.
