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Abstract

Objectives: Existing data on bonobo and chimpanzee dental eruption timing are
derived predominantly from captive individuals or deceased wild individuals. How-
ever, recent advances in noninvasive photographic monitoring of living, wild apes
have enabled researchers to characterize dental eruption in relatively healthy individ-
uals under naturalistic conditions. At present, such data are available for only one
population of wild chimpanzees. We report data for an additional population of wild
chimpanzees and the first dental eruption data for wild bonobos.
Materials and Methods: We collected photographs and video footage of teeth from
the open mouths of wild bonobos and East African chimpanzees of known age from
LuiKotale, Democratic Republic of the Congo, and Gombe National Park, Tanzania,
respectively. We scored the presence and absence of deciduous teeth from photo-
graphs and video footage to characterize deciduous dental eruption timing in these
two populations.
Results: Deciduous dental eruption ages in our sample fall within the range of varia-
tion previously documented for captive chimpanzees, but eruption ages are later in
wild than in captive contexts. We found substantial variation in deciduous canine
eruption timing, particularly among bonobos. One bonobo had a deciduous canine
present by 227 days old while another did not have a deciduous canine present at
477 days old.