Growth curves, dental emergence norms, and supplementary morphological observations in known-age captive orangutans.

Postnatal development in known-age captive orangutans was studied by collating new data from seven orangutans at Chicago Zoological Park, Brookfield, Illinois, with published and unpublished data from 76 additional captive orangutans. Norms were tabulated for deciduous and permanent dental emergence. Growth curves for weight and linear dimensions in females and males were compared in captive-reared and wild-reared subjects. Hand-reared and mother-nursed captives were compared with respect to dental emergence and weight increase. Differential relative growth of extremity segments was investigated. Pedigree data are presented relative to genetics of hallucal nail absence. Males of various ages were compared with respect to testis size and location and cheek-pad development.