Primary Tooth Mineralization and Exfoliation Ages Calculated from the Moorrees-Fanning-Hunt Study

Staging of the formation of teeth and shedding of the primary teeth are particularly useful for age estimation of archaeological and forensic specimens, as well as for gauging whether a child’s tempo of maturation is progressing within normal limits. Staging can be done using radiographs or with direct inspection of dental remains. Standards for the primary dentition are scarce, but obviously needed for young children. This note provides tables, by sex, of the normative ages of the mineralization of three mandibular tooth types (c, m1, m2) as well as of root resorption and times of shedding of these tooth types. The data are transformed from charts developed by Moorrees, Fanning and Hunt (1963 Am J Phys Anthropol 21:99-108). Conversion to numeric form is intended to aid in using these data for statistical comparisons.

Orangutans use compliant branches to lower the energetic cost of locomotion

Within the forest canopy, the shortest gaps between tree crowns lie between slender terminal branches. While the compliance of these supports has previously been shown to increase the energetic cost of gap crossing in arboreal animals (e.g. Alexander 1991 Z. Morphol. Anthropol. 78 , 315–320; Demes et al . 1995 Am. J. Phys. Anthropol. 96 , 419–429), field observations suggest that some primates may be able to use support compliance to increase the energetic efficiency of locomotion. Here, we calculate the energetic cost of alternative methods of gap crossing in orangutans ( Pongo abelii ). Tree sway (in which orangutans oscillate a compliant tree trunk with increasing magnitude to bridge a gap) was found to be less than half as costly as jumping, and an order of magnitude less costly than descending the tree, walking to the vine and climbing it. Observations of wild orangutans suggest that they actually use support compliance in many aspects of their locomotor behaviour. This study seems to be the first to show that elastic compliance in arboreal supports can be used to reduce the energetic cost of gap crossing.