To what extent does dental development reflect the slow tempo of human growth? What is known about the schedules of dental development in living primates? Reliable figures are surprisingly difficult to find. Even in humans, by far the most numerous primates and very much the most studied, the sheer variety of different approaches makes it difficult to arrive at a consensus view. In comparison, non-human primates are rare mammals with a restricted habitat, whose numbers can never have been very large. There are few studies of dental development, the sample sizes are small and conditions for data collection not ideal. Most come from captive animals and there is debate about whether or not these are representative of their wild counterparts.
Furthermore, the great majority of studies, human and non-human, record the eruption of the teeth through the gums. This is difficult to compare with fossil jaws in which the soft tissue is not preserved. The stages of tooth formation which are more clearly seen in fossils are necessarily assessed by radiographs in the living and it is not straightforward to match these with direct observation of the teeth themselves. Collections of exposed jaws and teeth from individuals whose age-at-death is independently known are rare and precious. They provide observations which are directly comparable with the fossils, but the number of specimens is small. Nevertheless, it is possible, through a combination of evidence, to address the question and to provide a background to the discussion of the following chapters.