But to determine whether subtle reproductive hierarchies might in fact exist, as in the case of female chimpanzees, veteran lion researchers Craig Packer and Anne Pusey of the University of Minnesota decided to take a closer look. (scientificamerican.com)
In Gombe, female chimpanzees often carry their infants with them into trees, making it very difficult for researchers to get accurate recordings from the ground. (sciencemag.org)
This may explain why female chimpanzees tend to go into hiding for weeks or months when they give birth. (newscientist.com)