[1] Lincoln Pk Zoo, Davee Ctr Epidemiol & Endocrinol, Chicago, IL 60614 USA
[2] Arizona State Univ, Inst Human Origins, Tempe, AZ 85287 USA
[3] Max Planck Inst Evolutionare Anthropol, Dept Primatol, D-04103 Leipzig, Germany
[4] Zoo Atlanta, Atlanta, GA USA